Four years in the making and with 34 years of experience and unrivalled reputation behind the company, Parasound’s new Halo Integrated amplifier/DAC had to be something special … and different to most other integrated amps on the market today.

The combination of highest quality components and the very latest technology result in a “superior” integrated amp, offering Halo separates performance in a single chassis.  Parasound’s Halo P5 inspired the preamp stage and advanced feature list, while its power amp stage employs the same John Curl circuit topology found it the Class A/AB A21 and A23 power amplifiers.  Its DAC decodes 384kHz PCM and native DSD using the latest ESS Sabre32 Reference version DAC.

The Halo Integrated Amp boasts the impressive feature list below:

• Halo Integrated: preamp and DAC;
• Coax and optical accept PCM up to 192kHz/24-bit
• Latest generation ESS Sabre32 Reference DAC (ES9018K2M)
• Asynchronous USB 2.0 supports PCM up to 384kHz/32-bit
• Native and DoP DSD decoding (Drivers for ASIO or WASAPI)
• Premium motor-driven Alps potentiometer volume control
• Dedicated high current headphone amplifier (TI TPA6120)
• Phono input for MM & MC with 100 Ω or 47k Ω load
• Front panel Aux input with automatic +12 dB gain stage

5 pairs of line level analogue inputs

1 pair XLR balanced analogue inputs

Balanced XLR and RCA left and right preamp outputs

Analogue bass management with high & low pass crossovers

Home theatre bypass input for surround sound integration

1 balanced XLR and 2 RCA subwoofer outputs

Bass and treble controls with relay bypass from remote or front panel

Rear panel IR input and IR loop output jacks

12 Volt input and output to triggers

Back-lit remote control with discrete buttons

0.5w standby power consumption meets Energy Star & EU specs  

The new Halo Integrated Amplifier is available in black or silver and in the UK now at a retail price of £2699.

Bringing “Haute Horology” watchmaking techniques and Formula One materials to Hi End Audio, Kostas Metaxas 40 years artistry in the state-of-the-art is embodied in his latest audio sculpture – “a perfect marriage of the arts of engineering [electrical and mechanical] and the fine arts of sculptural form”.

The IKARUS 2015 is machined from a solid block of either aircraft aluminium, copper or titanium. It’s totally bespoke and the modular electronics make it future-proof, says the company’s press release. The circuit boards can be CNC machined from 1mm solid silver coated clear polystyrene.

The new range is inspired by the breathtaking work of Ercole Spada and Pininfarina on racing cars of the 50’s and 60’s.

“It has taken little time for Australian firm MAS to receive worldwide attention. In France, the range of MAS Electronics has seduced us… Metaxas products belong to this rare category of electronics which achieve the essential and vital qualities of a good Hi Fi system which drive you to irresistibly listen and enjoy records one after the other”.

100% designed and engineered by Kostas Metaxas, each IKARUS is assembled by his sons – either Andreas or Alessandros Metaxas.

The familial passion in the fine and applied arts is inspired by the BUGATTI family.

The Elixir, from Budapest based Heed Audio is a compact five-input integrated amplifier with built-in phono stage and dedicated headphone amplifier, that is designed to provide the renowned Heed sound quality in a one box solution at a lower price point than the existing Heed products. A Class A headphone amplifier and enhanced MM phono stage provide increased functionally for users wanting a simple audio solution. Utilising the capacitor coupling principle borrowed from the Heed Audio TransCap amplifiers, such as the award winning Obelisk SI, ensures a similar sound quality and power output. The power amplifier output of 50W per channel at 8 ohms, or 65W into 4 ohms, provides plenty of power for the loudspeakers connected to the Elixir, enabling use of pretty well any model the user chooses. With four pairs of RCA line inputs, one pair of RCA MM phono inputs and two pairs of 4mm speaker connectors, along with a pair of pre-amp outputs, Elixir specifications are kept simple for the beginner, but afford expandability if so required.

Alpar Huszti, Heed Audio’s marketing and sales manager, says the Elixir, “Is the perfect amp to kick-start the new range that is specifically targeted at those new to world of hi-fi.” He continues, “A lot of hard work and effort has gone into researching and developing this product to create an amp at such a low price that is on par with the higher priced Heed Audio amplifiers, making the Elixir perfect to consumers looking to the first step, or who are looking for a cost effective and fuss-free way of playing their newly rediscovered vinyl collection.”

Elixir is available in two colours;  elegant silver and  ember-like black and is priced at £750.

Technics have announced the launch of their « Grand » range of components which will be made up of the SU-G30 (pictured below) network amp which will retail for £3500 (or thereabouts) and will, as the name suggests be an amp and streamer in one The second unit will be a music server ST-G30 which will allow users to rip their CD collection and save to the onboard Network Attached Storage drive.

In addition to these two units the company is also adding an all in one system to their Premium range called the Ottava SC-C500 which will have a CD player, streaming capability, will be wirelessly connected and will come with a pair of speakers. Price for this is going to be in the region of £2000.

There is also going to be a bnew direct drive turntable from the company, following Panasonics unveiling of a prototype at the IFA in Berlin. Interesting times…

If you like beautiful valve amplification then these new beauties from French company Jadis, should be right up your street!  The JA80MkII is an improved version of the JA80 which brings the compatibility with the new KT150 tubes and keep the compatibility with other tubes such as EL34, 6CA7, KT88, KT90, KT120, 6550, with a simple internal modification when switching from KT150 to the other tubes (requiring soldering). The power output is rated at 90W/channel in pure class A with the KT150.

The bias is still automatic.

Suggested public price with 20% VAT :15 420 EUR with EL34, 6CA7, KT88, KT90, KT120, 6550 & 16 200 EUR with KT150

The I88 integrated amplifier is the latest unit made by Jadis. The prototype was presented last year in Paris and they are proud to say that it is now available. Double push-pull of KT150, including remote control and digital input. The power output is rated at 90W/channel in pure class A and the bias is automatic.

Suggested public price with 20% VAT : 13 200 EUR

Dan Worth takes a listen to this well specified integrated amplifier (£2000) complete with its MM30 Media board (£1250)

The I32 is an upgradable 2 x 120wpc integrated amplifier from Primare which with its modular design allows for users to upgrade with a Media Board to allow for network streaming, USB computer input and iPod USB inputs… along with coaxial and optical DAC inputs allowing for a truly flexible jack of all trades amplifier. Along with the optional Media Board the I32 supports MM/MC inputs, two balanced XLR analogue inputs and three RCA unbalanced inputs.

Two UFPD amplifiers are housed in the heavy gauge screened metal chassis. The preamplifier is a completely separate implementation which has is own isolated power supplies in order to reduce distortion levels and to allow for a cleaner feed to the power efficient Class D modules, which in standby only consume a meagre 0.2W of energy.

Primare have ensured their signal path design is as short as possible and all signal treatment (volume, source selection and balance trims) are processed purely in the analogue domain.

Unbalanced inputs are converted to balanced and buffered by the Burr Brown OPA2134 op-amps and routed to volume and balance controls employing closely matched LM1972 balanced stepped attenuators. Source switching is made via high quality relays.

ULTRA FAST POWER DEVICE CLASS-D AMPLIFIER

The use of switch mode power electronics is gaining in popularity as the result of its lower energy consumption and as a way to squeeze more amplifier channels into smaller spaces. Unfortunately Class D amplifiers and their switch mode power supplies have traditionally deserved a reputation for poor audio quality, characterised by rising THD with frequency. Primare’s UFPD (Ultra Fast Power Device) technology provides for the possibilities of a full-range ‘audiophile’ Class D design. It is a Class D technology which has a consistent 26dB feedback loop gain across the entire audio bandwidth and is stable way beyond the audible frequencies. This is quite easy to achieve in conventional linear ‘continuous signal’ amplifiers, but much more difficult in ‘non-continuous’ high speed switching amplifiers.

Rather than have the amplifier and then the filter as discrete stages, the UFPD design integrates the two, making control with feedback much more immediate and accurate. The UFPD amplifier actively adapts the loop gain to keep the total loop stable during start up, clipping and current limit. It senses the changes to the filter output and compensates by applying the precise amount of feedback. This adaptive pole control allows for several more dBs of constant loop gain across the audio band and maintains performance irrespective of load (impedance) variations.

Primare’s UFPD treats all signals equally regardless of frequency or slew rate and has the ability to suppress the filter resonance entirely. Consequently THD is kept very low at all frequencies. With a very wide ‘load independent’ frequency response UFPD is able to drive any speaker while maintaining control and accuracy.

Build quality is really nice with the thick front panel, heavy gauge chassis, powder coated and nice shiny, smart looking knobs and buttons on the fairly sparse (the way I like it) front panel.  There’s a centrally aligned screen for display of source and volume, along with clear indication of muted playback. Although the rear of the unit is busy with many connecting sockets the layout is nicely grouped and organised.

The included remote control is packed full of buttons being a system remote for other linked Primare components – functional it is, but it’s nothing to write home about and is plasticky and lightweight, but hey-ho, it’s only a remote and I personally tend to never use them anyway – it screws up my daily exercise routine of having to get up and turn the volume knob by hand!

SOUND

After a good 40 minutes of warm up time the I32 really begins to kick into gear, producing fast, clean beats and a massive open and truly transparent midrange with an airy top-end which demands the listener’s attention. Up until the 40 minute mark point music sounds a little flat and noticeably slow.

Soundstage width is absolute magic with every nuance and micro detail being fully formed in all its robustness and clarity. Class D often leaves a lot to be desired when fleshing out notes with textural timbres and characterises itself all too often with leanness, limp bodied, sterile or cold taints, but the I32 is rich and full bodied in-between and beyond of the speakers. Tonal information is displayed in its full entirety regardless of image placement. For me, when I hear an amplifier which can reproduce full natural tones throughout the entire listening area, rather than suggestions of detail spread out, makes me instantly want to investigate the product further and adds a real first time excitement to the sound.

Although the richness of the sound signature replicates instruments and vocals incredibly well, the very lowest bass-line of the I32 takes a little getting used to. I’m used to having a slightly looser and gentler roll-off to the bottom end whereas the I32’s bass is full and tight, presenting more detail than say my Jeff Rowland integrated and has a tightness that is coupled with weight that defines the lowest notes further and more accurately. With the Rowland it colours the bottom end with a little bloom and allows for the lowest of registers to gently fade into the abyss – the I32 doesn’t suddenly stop or roll short in anyway, it has a point where the note ends, which after a little while of listening made me believe that it had a certain truthfulness about it. When playing upbeat music the I32 is so bouncy and musical it made me sad to revert to the Rowland, especially with the lively and energetic music I play during the daytime.

Listening in the later parts of the day to some Norah Jones allowed me to appreciate how transparent the sound is from this amplifier. Looking right through her vocal, each tender subtlety of her voice had as much prominence in the soundstage as the lightly rubbed strings to one side of the stage, imaging just outside of the left speaker and allowing it to disappear. I was offered up a timbre and naturalness that Class D in my experience simply doesn’t normally achieve. I have had the Rowland Class D pre and power for a while now and although tremendously good and better than the Primare in certain ways, just couldn’t expose details in such an uncoloured and effortless manner.

Top end again has such a completeness to it that when analysing it closely it’s very difficult to single it out completely and the overall cohesiveness of the amplifier draws you straight back into the full sound (and away from writing the review process!). Clarity, air and sparkle must be the key ‘buzz’ words for the I32’s treble performance, though I’d suggest that there is a very marginal and discrete decibel drop to finely align it with the rest of the frequency response. Notes are very concise and the response of the upper mid-range gives the treble body and thickness especially to strings and cymbals.

Listening to electronica with the I32 shows such pace in the treble as well as the entirety of the sound. Speed and timing seem to be really very accurate and bass notes dig really deep into what is a terrifically dark background.

Listening to Fink’s live album ‘The Wheels That Turn Beneath Me’ allowed for really insight again into the performance. The crowd’s applause was vast and wide and I’ve heard this album with a few pieces of equipment sounding a little nasal and congested or strangled, but the dynamic impact of the ultra fast transients which the I32 produces really gave some wallop and slam to the brisk, heavy, singular drum beats on ‘Perfect Darkness’.

CONCLUSION

I really could go on and on exploring and explaining my findings for track after track and I could have quite easily written this conclusion to say ‘If the Primare I32 is in your purchase budget and you require a new amp look no further’.

I would have loved to have some ATC’s here with this amp and after the review I will be experimenting and playing with other complementary kit as I just enjoyed the amp so much.

The I32 will take all your musical tastes and run wild with them. It’s not coloured or warm, it’s rich and vibrant, it’s not sterile or analytical, it’s clean and accurate. The I32 is fast, controlled and utterly poised, it won’t bite you if you give it some volume or listen to Spotify Premium with the High Quality button turned on and it won’t feel limp or lifeless when you want t listen to something more beautiful.

With dynamics that match the music and an effortlessness that is just so noticeably true, the I32 will remain a favourite for some time to come!

Build Quality – 8.8/10

Sound Quality – 9.2/10

Value For Money – 8.8/10

Overall – 8.93/10

Dan Worth

Designer’s Comments 

The I32 /MM30 combination marries the latest model in the line of 30 series integrated amps from Primare with digital-to-analogue conversion and streaming technologies. As a result of the modular design approach in the I32, the DAC and streaming capabilities, along with Bluetooth connectivity, can be easily added to the integrated amp by way of the MM30’s slide in board. This modular approach further allows for future upgrades to be taken advantage of as they arise.

The good stuff in the I32 includes our proprietary UFPD (Ultra-Fast Power Device) Class D amp modules. The term “Class D” is sometimes misunderstood as meaning a “Digital” amplifier.

While some Class D amps may indeed be controlled by digital circuits or include digital signal processing devices, Primare’s UFPD modules operate entirely in the analogue domain. Basically, the UFPD amplifier module takes an analogue input sine wave and converts it into a high frequency pulse width modulated square wave for amplification. This square wave is then filtered, resulting in an amplified analogue sine wave at the output.

In conjunction with UFPD, Primare uses an isolated PFC (Power Factor Control) technology in the power supply, which controls the current from the mains voltage so that it is a pure sine wave with the same frequency and phase as the mains voltage. This means that even if 1000W is taken from the mains, other equipment in the room will not be affected. Its presence becomes virtually invisible to the mains voltage! The isolating stage of the converter works in a ZVS mode and as a result, the switch flanks contain a lower quantity of harmonics, providing lower EMI and a clean environment for the amplifiers to work in.

The dual UFPD modules in the I32 are supported by an audiophile circuit topology involving an isolating heavy gauge alloy steel chassis and an isolated pre-amp section fed by a dedicated power supply.

The MM30 upgrade uses a SRC4392 sample rate converter in conjunction with a Burr Brown PCM1792 24/192 DAC, running continually at 24/192. Incoming data at rates other than 24/192 are up-sampled to 24/192 to ensure the optimal operation of the DAC. For reliable 24/192 operation, we’ve chosen XMOS because it offers an integrated communication hub hosting the MCU. Please note: 176.4kHz is not supported by XMOS on MM30 (176.4 is supported over network). Essentially the streaming/DAC topology is identical to that used by our £2K NP30 network player, so in the I32/MM30 you’re getting a great amp and player in one, for a great price.

Terry Medalen

French company Devialet have taken the audio world by storm since they launched and Stuart Smith now takes a listen to their £5590 Ensemble package.

Let’s get one thing out of the way from the outset shall we – the guys at Devialet certainly know their marketing and the hype behind the brand has been at fever pitch pretty much since the French company launched. However, aggressive marketing has ensured that when talking about Devialet you tend to get two very distinct responses; the “It’s all style over substance marketing hoo-hah” on one side and “It’s the best thing sliced baguette” on the other. Given some of the rooms using Devialet amplifiers at this years Munich High-End it certainly seems to be the case that many of the high-end speaker brands have fully embraced Devialet’s amplifiers, one case in point being the Leedh room.

Here for review we have the Devialet Ensemble which is a package deal of the Devialet 120 (we actually had the 200 sent) and a pair of Atohm GT 1 Devialet Special Edition loudspeakers.

Devialet use something they call Analogue Digital Hybrid technology at the heart of their system which they say gives users the best of both digital and analogue worlds. ADH works by connecting a class A analogue amplifier which drives the output voltage to the speakers and then several class D amplifiers are added in parallel and act as slaves to the class A amp to give the speakers the current they need to sustain the output voltage.

Before the ADH section Devialet use a “Magic Wire” DAC which “implements the DAC at the core of the class A amplifier, in order to reduce the parasitic, musical-impeding phenomena such as noise and distortion”. Again inn simple terms the Texas Instrument PCM1792’s output is converted directly to a high-voltage without any processing in-between.

Power supply is onboard and provided by a switched-mode psu with “Power Factor Correction” which Devialet say is able to provide huge peak power delivery and an efficiency of 85%.

FIRST IMPRESSIONS

The packaging of the Ensemble is absolutely fantastic and you certainly get that Christmas morning feeling that we bang on about all the time – that feeling of having spent a good deal of money on yourself and the expectation you get when the item finally arrives and you start to unpack it. Certainly very high marks here for Devialet and something many could learn from.

The amp itself is a thing of great beauty depending on your viewpoint, with its low profile form and silver, chromed, mirrored finish. The quality of the chassis cannot be questioned and is certainly of a high quality being milled from a single billet of Aluminium. There are no knobs or controls on the amp save a single power button which also indicates the state of the amp and the function selected.

The remote is the most gorgeous remote I’ve ever had the pleasure of using with its large rotary knob for volume. It’s just so tactile and screams touch me!!! Yes there’s a good deal of Le Bling on offer here, but I don’t think it’s necessarily over the top and because of its size and low profile the whole thing is pretty unobtrusive should you want it to be…if you like to show off you can even hang it on the wall.

The speakers that come with the Ensemble package are Atohm GT1 Special Editions that have been designed by Devialet, have an impedence of 6 Ohms and are 89dB sensitive. It’s a two way bass reflex system measuring 330 x 200 x 265 (mm) and it all looks pretty conventional and quite nice in the gloss white finish. The tweeter is a 1 inch soft dome affair and there’s a 6” main speaker. I did have the protecting baffle for one of the woofers drop off soon after unpacking but these are simple to slot back in.  Of course the speakers have been treated to Devialet’s SAM process and when SAM is activated on the “amp” bass response is quoted as being as low as 23Hz as opposed to 39Hz when SAM is not engaged. For the purposes of this review the speakers were placed on stands that brought the tweeter pretty much to ear height.

SET UP

Set up of the Ensemble system is a little different to the usual plug and play scenario most of us are used to but once you read the manual and instructions it’s all pretty much plain sailing. Round the back of the “amp” there’s a little slot for an SD card and you go online to your personal “Configurator” where you can decide what inputs do what, what processing you have running, as well as loads of other things you can tweak and play with, more of which later.

All this sounds a bit complicated if you are used to more conventional set ups but it isn’t really and it means that when Devialet come up with a new firmware update or a new feature you can download and install it quickly, easily and for free.

The procedure for set up goes – Go to your computer, log in to your Devialet account and go to the Configurator, add the stuff you want to add and get the inputs doing the function you want them to, download the file you are presented with, copy it to the SD card, pop the SD card back in the back of the “amp” and everything automatically installs when you turn the amp back on.

I liked this feature a lot and it effectively means you get free upgrades and new features for life and I can see that when it comes to awarding a value for money score for this package it’s going to be quite interesting.

SAM

SAM stands for Speaker Active Matching and it’s a DSP built into the Devialet system with the idea that “enables the precise adaption of the sound signal to the specifications of your speaker model”.

PHONOSTAGE

I’m getting a little ahead of myself here but wanted to talk a little about the Devialet’s phonostage before we got any further down the line. This feature was introduced at this year’s Munich High-end and is basically a phonostage you download from the Configurator and add to your Devialet set up. They say it’s the most advanced phonostage ever and the specs are pretty impressive, with a whole host of equalization curves being available at the touch of a button on Configurator.

You get to set the loading for your cartridge, and should you fancy a change of cartridge it’s a simple matter of going to your account and changing it, download the new file, pop it on the SD card, insert this into the Devialet and off you go.
I was very keen to try the phonostage feature and I have to say I was a little sceptical about the whole thing. You have to keep in mind that all this equalization and loading etc is done in the digital domain, but to be fair the results are pretty impressive with me getting very good results from vinyl using the AT09 cartridge I have at the moment. Bass was a tad bloomy when compared to my much loved Graham Slee Elevator/Reflex combo but it’s very hard to knock a product that Devialet are essentially giving away for free to their customers. I’d certainly be happy to listen to vinyl on this set up for all but the most critical of listening sessions. For folk with a turntable and a decent collection of records they want to dip into from time to time it will prove to be more than acceptable. I tried the phonostage with a good range of genres and it responded very well. It is not “the best phonostage in the world” though and there was to my thinking a shortfall in dynamism with our current test track “Contact” by Daft Punk lacking a little oomph. The stereo image is good and stable and instruments sit properly in the mix with there being a good analogue feel despite the fact that this is all digital. It’s clever stuff as is the whole system.

TONE CONTROLS

Does anyone remember tone controls on amplifiers? Back in the dim and distant past all amps came with a bass, treble and balance control so that you could tune the sound for your taste and for your room conditions. They went out of favour in the mid-eighties when there was a movement towards the preservation of purity of signal path. Yes I used them a bit but still found myself preferring a flat setting. However, I do see these as being useful and given this is all digital the argument about short signal paths etc is pretty moot.

OVERALL THOUGHTS

I lived with the Ensemble and used it as a package, as the vast majority of people will, and for most of the time I chose to stream from my laptop using the Airplay set up… download the software to the computer, activate it, get it running and you’re off.

Overall you get a very good sound indeed and this package will appeal to many. The SAM settings do help a good deal to my ears and I felt that there was a tightening of the bass which in turn offered up a more coherent sound and so I used Ensemble with SAM engaged pretty much constantly.

There is a good soundstage thrown by the combo and the mix is presented accurately enough before you, with instruments appearing to have their own space in the mix. This I feel is one of the benefits of smaller standmounts and gives you a sense of being in front of the mixing desk and though the image felt accurate here it wasn’t as deep as I’ve heard and you undoubtedly don’t have the speakers “disappear”.

As regular readers of my reviews will know one of my pet peeves is wooly and flabby bass that hangs around after the note is finished and here the Ensemble does very well indeed – on one of our torture tracks for bass (Todd Terry’s Blackout) the low frequency, electronic “whoomph” felt like I was listening to a bigger pair of speakers and they do go low, though not in the same way a bigger speaker can. This whoomph I mentioned on this track is actually a pretty complex synthesized noise and there is good detail in the sound here.  The amp really did seem to grip the speakers really well in these lower frequencies, but as a system bass never feels like it is taking over and there is coherence across the spectrum. On more percussive techno there was attack and bite to the music which was dynamically exciting to listen to.

On more gentle music with the mid-frequencies being the highlight (Fleetwood Mac’s Songbird) there is a clarity and flow to the vocal with a good feeling of the recording space, with an absolutely silent background allowing the quiet guitar on the track to be easy to follow and hear. You do get a good deal of detail, but that is not at the cost of being fatiguing, and so you can listen for long periods and at high volume without feeling the need to take a break. The Ensemble isn’t a force it down your throat combo either and whilst the detail in a recording is easy to hear, you don’t become fixated on it to the point of distraction…this is a good thing and will appeal to those wanting an untaxing listen.

One issue I did have with the sound at times was a slight sensing of pixilation at the very upper frequencies and this had me thinking “I’m listening to digital” here. Please note I have used the phrase “at times” here as this pixilation or digitizing seemed to appear at certain times of the day and I am assuming that this is some kind of interaction between the power from our mains having some effect. At the time I didn’t have a mains conditioner to hand and so couldn’t say this is fact or not. For the vast majority of the time the top end was clear and crystal like with lots of air around the instruments with David Crosby’s Croz album in hi-res sounding fab.

CONCLUSION

I really didn’t want to like the Devialet Ensemble but ended up having a blast with it. For your money (available for £5590) you get a very good looking, very versatile hifi that is pretty much future proof. This is a real one box system solution given there is connectivity for pretty much anything you can throw at it. New innovations, system updates and all the free stuff Devialet keep coming up with actually make this pretty good value for money.

The Ensemble isn’t the last word in fidelity in absolute terms but for the money there is certainly very little that I found I could criticize and remain honest.

Devialet will shift huge numbers of this combo I guess and as the technology advances so will your system…at no extra cost.

The “could I live with this” question has to be asked and for me it’s a hands down yes. Yes, our reference system (also using class D amps incidentally, but with a valve pre in place) gives me more of everything, but then for the cost of my speakers alone you could have the whole kit and caboodle from Devialet gracing your living room and not wanting to take over your space completely. Most definitely if I was looking for a one stop solution that allowed me to listen to my tunes effortlessly this ensemble would definitely be on my shortlist…though it has to be said it’s a swine to keep looking shiny and dust free!

Build Quality 9.0/10

Sound Quality 8.75/10

Value For Money 9.0/10

Overall 8.92/10 

Stuart Smith

Classé has announced the expansion of its popular Sigma series to include a new monaural amplifier. The first three Sigma series models, launched earlier this year, were designed to deliver a compelling performance and feature set at prices below the entry level of other high-end brands but within easy reach for anyone considering the top-of-the-line offerings of more mainstream companies. The Sigma MONO broadens the appeal of the Sigma range with a powerful amplifier, conservatively rated at 350W into 8 ohms and 700W into 4 ohms.

“In the short time they’ve been available, our proprietary Sigma series amplifier designs have been showered with praise from numerous audio critics and consumers worldwide, “said Dave Nauber, President of Classé. “The Sigma MONO builds on this innovative platform, pushing the performance to heights that surprised even us – and we’re pretty hard to surprise!  

The pure, effortless sound that is the hallmark of the Sigma MONO derives from an unlikely source: a massive switch mode power supply,” . “Critical portions of the amplifier’s circuitry surpass what is available in the two- and five-channel Sigma models. A new analogue input stage, modifications to the operation of the output stage, and new output filters are employed to optimize the performance of this high-powered monaural amplifier.”

A special pass-thru feature allows the input signal to be forwarded to a second amplifier for bi-amplifying or to drive a subwoofer amplifier. This allows the amplifiers to be located closer to each speaker: a single long interconnect can be used to connect the preamp to the first amp, followed by a short interconnect to the second Sigma MONO – or even a third and a fourth.

The US retail price for the Sigma MONO is $4,000, with availability in October.

Zesto Audio Will debut their Eros 300 Monobloc amps at this year’s RMAF.

Eros 300 is a pure Class A design offering 150 watts per amp with both 4 and 8 Ohm taps. It has SpeakOn and standard loudspeaker binding posts and uses a push-pull ultra-linear design with no negative feedback.

Valve compliment per amp is a matched sextet of KT88s and two gold pin ECC82s (12AU7).

Each unit is handmade in the USA and costs $19 900 per pair.

Pass Laboratories, Inc. is demonstrating the most powerful of its two new integrated amplifiers, the INT-250 and INT-60, at the 2015 RMAF.

The INT-60 features the same power supply and output stages, along with the iconic glowing meter, as found on Pass Labs’ Point 8 amplifiers. The new model features Direct Access buttons for the four inputs on the faceplate, a digital level display, plus a Volume Control knob and Mute button. On the back are four line-level inputs, a line-level output, and two pairs of Furutech speaker binding posts.

The new INT-250 ups the wattage from the INT-150’s 150 watts to 250 watts per channel.

Price: INT-60 ($9,000) and INT-250 ($12,000)

The INT-250 can be seen in Tower Room 1021 during the 2015 RMAF.

Amplifier Technologies Inc, has added a new series of amplifiers designed by their president and chief engineer, Morris Kessler.  The 4000 series amplifiers, available with 2 to 7 channels, share the design philosophy and circuit sophistication of ATI’s award-winning 6000 Series amps with power output reduced to 200W RMS per channel at 8 ohms and 300 W RMS at 4 ohms. This “signature series” comes complete with a facsimile of Kessler’s signature on the main panel. Beyond Kessler’s personal identification, these amplifiers share these key features with the 6000 Series Signature amps:

1. Fully balanced, differential amplifier design with two output stages per channel but with only a single input stage.  The advantages of balanced designs are retained and noise is further reduced by 50%.

2. Current feedback instead of the more common voltage feedback because ATI feel that current feedback amplifiers are faster with virtually unlimited slew rate and are better able to reproduce today’s best music and film.

3.Thermaltrak output devices:  Unlike traditional designs where external diodes attached to the heat sink track the amplifiers operating conditions to adjust bias, Thermaltrak devices have the diodes in the same package as the transistors so bias is optimised in real-time.

4. Dual DC servos per channel to control DC offset.

5. Dual toroidal transformers with independent secondary windings.  Electrically, each amplifier channel has its own transformer. 

All the amplifiers in the 4000 series are rated at 200 Watts RMS from 20 Hz to 20 kHz with no more that 0.03% THD at 8 ohms with all channels driven and 300 Watts RMS at 4 ohms under the same conditions.  Signal-to-noise ratio is typically 126 dB referenced to full output so each amplifier in the series is capable of playing back the full dynamic range available on today’s lossless recordings.

Pricing:                                                               MSRP

AT4002 Stereo Signature Amplifier                       $2,995.00

AT4003 3-channel Signature Amplifier                   $3,595.00

AT4004 4-channel Signature Amplifier                   $4,195.00

AT4005 5-channel Signature Amplifier                   $4,795.00

AT4006 6-channel Signature Amplifier                   $5,395.00

AT4007 7-channel Signature Amplifier                   $5,995.00

All ATI amplifiers are available in standard (17”) and rack-mount (19”) chassis with domestic (117V) of Export (220 to 240V) chassis and are covered by ATI’s 7-year transferable warranty. Dimensions (H, W, D):  7 7/8” x 17 ¼” x 17” (200 x 438 x 432 mm); Handles protrude 1 ¾ (44.5 mm); Add 1 ¼” (32 mm) for input/output jacks.

Quad continues to mark its 79th year with the arrival of Artera, their new range of high-performance audio electronics. First to arrive are the Artera Play and Artera Stereo; the Play is a CD player, DAC and preamplifier combined in a single chassis, while the Stereo is a power amplifier sporting Quad’s famous Current Dumping technology.

Quad gave its team of designers and engineers a specific brief for Artera: “combine the qualities that have made Quad one of Britain’s most revered hifi marques for many decades with fresh industrial design and the very latest high-performance audio technologies”. To this end, Quad enlisted the help of Rodney Mead, the man responsible for the styling of many classic Quad products in the 1970s, ’80s and ’90s, to brainstorm design concepts that would lead to Artera.

Artera have a textured aluminium front panel, thick glass top and CNC-routed heat sinks on either side. The housing provides a rugged structure that resists interference from external vibrations, and the Artera Play’s fascia incorporates a touch-sensitive control.

Quad Artera Play 

At the heart of the Artera Play nestles the ESS Sabre32 9018; a 32-bit, eight-channel hybrid multi-bit Delta-Sigma DAC. This is Quad’s first component to utilise the ESS Sabre DAC, and external digital sources can benefit from it via a range of digital inputs. These include USB, with support for PCM data up to 32-bit/384kHz and also DSD64/128/256.

For CD replay, a new slot-loading mechanism buffers data from the disc before feeding it asynchronously (in order to minimise ‘jitter’) to the DAC section. Four digital filter options enable users to tailor the Artera Play’s sound, with both CDs and external digital sources, to suit personal taste and the nature of the source material.

The Artera Play’s preamp section boasts a balanced Class A output stage. Two coaxial and two optical inputs cater for external digital sources alongside the USB input, with a pair of RCA phono inputs handling analogue sources. Analogue outputs are supplied in both single-ended RCA and balanced XLR varieties; a pair of digital outputs (optical and coaxial) and a 12V trigger output complete a comprehensive array of connectivity options.

Quad Artera Stereo 

This compact yet potent power amp sports the latest iteration of Quad’s famous Current Dumping topology, first introduced in the Quad 405 – one of the most lauded British audio components of all time and still the only amp design to have earned a Queen’s Award for Technological Achievement.

Current Dumping is essentially a method of marrying Class A amplification with the greater efficiency of Class AB. A high-quality, low-power Class A amplifier provides the signal quality, while a high-power current dumping section delivers the muscle to keep the speakers under control. These two amp circuits are combined via a network to impose the finesse of the Class A output onto the power of the current dumper.

The Artera Stereo’s power output is conservatively rated at 140W per channel into eight ohms and 250W into four ohms, ensuring any speakers – including Quad’s classic ESL electrostatic designs – can be driven with ease. Connectivity options comprise single-ended RCA and balanced XLR inputs, a 12V trigger input and high-quality speaker binding posts.

Speaking about the inspiration behind Quad’s new Artera range, Peter Comeau, Director of Acoustic Design at Quad’s parent company IAG, commented:

“The traditional spirit of Quad has always been to cater for the latest developments in music storage and playback, whilst continually striving to meet the standards inherent in the company’s motto, ‘the closest approach to the original sound’. Thus, the Artera series of components includes full digital and analogue playback capabilities with the resolution and accuracy to replay all current and future high-resolution audio sources with the most musical presentation.

“However, today’s consumers are often bewildered and confused by the multiplicity of inputs and controls on modern hi-fi equipment. At Quad, we have never believed that you have to be a ‘hi-fi geek’ to be able to play music at the highest performance level. Artera therefore simplifies the user interface, leaving an uncluttered appearance that is welcoming to all users as well as looking beautiful in the home.”

The Artera Play and Artera Stereo are available now, with a choice of black or silver front panels and RRPs of £1,399.95 and £1,499.95 respectively.

Arcam will be previewing their 2016 AVR range in Dallas this coming weekend, to coincide with the CEDIA 2015 Show. They will be showing (but not playing) samples at the Arcam Solo Event on Weds 4th November.

“These new AVR’s are quite simply, the highest performing AV receivers Arcam has ever made and some of the finest in the world” says the company’s latest press release.

The new Arcam AVRs are serious video & audiophile products that are equally at home with high-resolution surround or two-channel music.

ARCAM AVR850 £4200. The new champion AVR, top of Arcam’s range and with the power and performance of 7 channels of Class G Hi-Fi Amplification, combined with state-of-the-art 4k video and exceptional connectivity.

ARCAM AVR550 £2200. Most of the above, with a bit less power and Arcam’s finest conventional amplifiers. 

ARCAM SR250 £2500. A unique Stereo AV receiver. The power and performance of a High-end Class G Hi-Fi amplifier, with the connectivity of a world-class AV amp. Literally the best of both worlds for people who want great Hi-Fi and a new breed of Movie and TV sound.

Arcam of Cambridge: PREVIEW: SR250 unique stereo AV receiver. The power and performance of a Class G Hi-Fi amplifier. The connectivity of a word-class AV amp. Literally the best of both worlds.

All include:

• 4K (UHD) video compatible including HD ULTRA upscaling
• 7 x HDMI 2.0 inputs with HDCP2.2 – 3 HDMI outputs – ARC compatible
• Auto setup with advanced  “Dirac Live for Arcam” room correction
• Ethernet, RS232 and IR control for Custom Install
• Free MusicLife iOS AV Streaming and Control app
• Music networking including Spotify Connect
• On board regulated power supply for rSeries digital input components

CLASS-G Amplifiers

The AVR850 and SR250 use Arcam’s u class G amplification, which allows the them to run in full class A for most of the time and then switch into class G for huge reserves of clean power. To hear what this delivers, just try a piece of music or a movie you thought you knew.

The 850 and 550 are 7.1 receivers and can implement Dolby Atmos brilliantly, in a typically used 5.1.2 channel cinema system. Arcam have chosen not to install and charge for multiple power channels that will probably never be used. For enthusiasts who want to implement full-fat 7.1.4 Dolby Atmos systems, Arcam will offer a matching 4 Channel Power amplifier in Spring 2016.

Icon Audio’s MB 30 SE mono power amplifiers use no PCBs in their construction and come with a two year guarantee. Stuart Smith takes a listen to these £2199 amps. 

Icon Audio are based in Leicestershire in the UK, where, headed up by David Shaw, they have been designing amplifiers and other valve based electronics since 1999. Their website is at pains to point out that they do not use PCBs in their amps and that all their amps are hand built with quality materials that are designed to give long service, using parts that are easy to source. They also stress that there are no transistors or microchips in their amps and that their design is “pure valve’.  I like this philosophy a lot and it immediately instils a level of confidence in the product and the company. Quality audio components are not cheap items and longevity of service will be a major factor for many when parting with their hard earned cash and Icon’s two year guarantee and full back up service is a good sweetener.

The MB30 SEs arrive very well packaged, with good, easy to follow instructions and so within a matter of minutes you can have them up and running in the system. Biasing is a doddle…flick the switch on the front of each amp to bias, fiddle with the little screw atop each amp until the large and easy to read VU meter on the front gives the desired reading and that’s it, ready to play some tunes.

Construction appears to be solid and the amps certainly feel nice and weighty – they weigh 12KG each, much of which will be down to the transformers used. The amps are point to point hand-wired and use silver plated copper PTFE cable.

Valve stock on the model supplied is a 5AR4 rectifier, a CV181 drive valve and a KT150 output valve (though you can use KT88/90s should you wish). The online blurb says that the amps come with the KT120 so I enquired and was told that the KT 150 will work fine. The valves fit in their sockets tightly and very securely.

The KT 150 is a relatively new valve from Tung Sol and it is finding favour with many in Audioland, as well as being used by tube giants such as Audio Research in their Reference 75 SE, Reference 150 SE and Reference 250 SE. The valve is relatively cheap coming in at less than $100 in the US and available for £54 in the UK which makes good sense in a relatively budget amplifier like the MB30 SE, it also makes sense when it comes time to buy new valves.

The output from the MB30 SE is pure Class A with a Class A triode front end. You have a little toggle switch on the front of each amp marked “Triode” and” Ultralinear” where the amps will offer up 16W and 27W per side respectively. ” “Ultralinear” is a combination of triode and pentode, in order to get good power with the triode sound” says the Icon website.

Also on the front of each amp you have the aforementioned VU meter (I’m a sucker for VU meters) which will show your power output or, when the toggle switch is flicked, biasing information. Round the back you’ve got an RCA input, 4 and 8 ohm speaker terminals, the IEC power input and another little toggle switch for hi and low sensitivity. This latter makes pairing with your preamp much easier!

The amps are slim, neat and to my mind look very nice indeed with fit and finish being good for an amp costing £2199.95.

THE SOUND 

Throughout the review process I used the usual suspects of Coffman Labs G-1A pre, the VAD DAC, Analogue Works turntable with Graham Slee Elevator EXP SUT and Reflex phonostage and a dedicated music laptop running J River. Cables are by Tellurium Q, Merrill Audio, IsoTek and Vermouth Audio.

On first powering up the amps you get the immediate sensation of them being very quiet indeed, with the only nasties I could hear being the usual slight hum from the pre, which is only audible when you get your lugholes close to the speakers, which again are our usual hORN Mummys.

The Mummy’s are sensitive beasts and I used to run them pretty loud with my 18W 300B amp (Parallel Single Ended) so it seemed the natural thing to start off with the amps in triode so see what their 16Watts can do.

I’ve been hammering Miles Davis’ Kind Of Blue of late and with the MB30 SE I’m not disappointed. There texture to the music that’s not dissimilar to how I remember the aforementioned 300Bs being (this is a good thing). This textural quality (particularly to the midband)  is underpinned with strong bass that seems to be a tad more controlled than that of my old amp, but not as controlled as the Tellurium Q Iridium (20W of transistor Class A) I’d been using up until recently. At the top end there is good air and space around the cymbals and brushwork on the snare, but it is definitely in the mids, and particularly upper-mids, where this little amp shines. Trumpet cuts through the other instruments (as it surely should) and you are left feeling that what you are getting is all very natural and unforced music. There’s rasp and there’s a true to life character to the trumpet that belies the relatively modest price of the MB30 SE …a sense of musical ease where the tunes just flow freely and effortlessly.

On more modern dance oriented music (Madonna’s American Life…no, it’s really very good) the bass is relatively tight and fast and this is really where I was expecting this amp to fall down. Don’t get me wrong, this is not the last word in bass control but it ain’t bad at all! Hats are crisp and appear in their own space, whilst Madge’s vocal comes well forward in the mix. There’s enough grunt in Triode mode to get things across as they should, but with this kind of music I preferred the amp switched to Ultra Linear – there just seemed to be more oomph, which this genre demands. I’ve compared this amp to my old 300B amp in this review but here the Icon Audio amp clearly has a bit of an edge, particularly in the area of controlling the bass…and the option of switching from Triode mode to Ultra Linear is a big bonus.

On rock (Deep Purple’s Made In Japan) the bass test track of Smoke On The Water is very good, grunty and controlled in Triode mode, but again flick the switch and you get a little more, particularly down low where it’s needed. There’s good pace and timing to the music and you’re never left feeling that this is a slow amp in any way – instruments stop and start as they should, but where an instrument hangs in the mix you also get this effect really nicely. The Live in Japan record is a good one and you can clearly “see” where the musicians are on the stage  – even though on the front cover Mr Blackmore’s appears to be at the wrong side of the stage.

On female vocals there’s a lovely rich texture apparent and lovers of this kind of music will be well pleased with the Icons. I know I keep harping on about the 300B amp I used to have, but again this is the feeling I get with this kind of music. The mids are just so smooth and silky you’re left in no doubt that these amps have been voiced with the audiophile palette in mind. However, this mid-band smoothness has not been achieved at the expense of the other frequencies and there is the impression that these are nicely balanced amps.

The Icon’s aren’t the last word in ultimate definition when compared to our reference amps, but what they lack in absolute resolution they make up for in sheer musicality that keeps you listening for hours on end.

CONCLUSION 

In the grand scheme of things these are relatively inexpensive amplifiers for what you get in terms of fit and finish… and the all important sound quality. There are compromises in terms of absolute resolution when compared to our reference amps (as there is always going to be at this price-point) but these are damned musical amps that just get on with delivering the goods in a highly enjoyable fashion. They are simple to set up, quiet and fuss free and have enough power to keep all but the least sensitive of speakers happy. The Icons always had a feeling of control over the speakers, whilst offering up a smooth presentation that is pretty addictive.

As always the proof of the pudding is in the asking of the “Could I live with these?” question and the response has been a resounding yes.

Sound Quality – 8.55/10

Build Quality – 8.60/10

Value for money – 8.65/10

Overall – 8.60

Pros:

Well built and smooth sounding amps with a distinct “audiophile” and musical character

Extra grunt available at the flick of a switch

Easy to set up and use

Cons:

Little to criticise at this price-point, but not as resolving an amp as the reference we measure against

Stuart Smith

The Unico range of hybrid hi-fi electronics from Unison Research has garnered a strong reputation with audiophiles around the world in recent years. The new Unico 150 dual-mono integrated amplifier has been designed from the ground-up to take the mantle of flagship in the Unico range; superseding the well-established Unico 100 model.

ASTA AUTUNNO 2015

“The Unico 150 amplifier has been designed to fulfil both high-end audiophile and highly scientific criteria. This dual-approach to development has led to the creation of a product that is completely different from anything else Unison Research has ever released, and the result is something truly unrivalled on the market; a powerful, great- sounding amplifier with only three active stages (two tube and one MOSFET stage)” says the press release from Henley Design who distribute the range in the UK.

The Unico 150 is an integrated amplifier designed to accommodate a variety of sources via its three RCA and two XLR pair inputs. It’s also designed to fit into most existing systems, with its fixed and variable RCA outputs as well as the bi-wirable speaker terminals. The large casework is built to the same standards as previous Unico designs, but the Unico 150 is the first to boast a new three-plate front fascia that adds an aesthetic enhancement over its predecessors. Operation is simple via the front-panel controls or the supplied RC2 system remote.

ASTA AUTUNNO 2015

The Unico 150 uses a three-stage circuit and all of the gain – and with it the core sound character of the amplifier – is controlled by the first two Pure Class A tube stages. The input stage uses two ECC83 triodes in totem-pole configuration, while the driver stage uses two 6H30 triodes in totem-pole configuration for “near-flat distortion, minimal output impedance and well controlled gain”. A high- quality but entirely passive ALPS volume control and armoured input switching relays are used.

The whole pre-amplifier section is directly coupled to each channel’s MOSFET power stage to achieve a consistent, with optimal linearity achieved within 10 minutes of being switched on (nominal linearity is achieved in under a second). The Unico 150 has been designed to drive a wide-variety of loudspeakers.

The Unico 150 boasts purpose-selected power transformers and the power section has also been configured to give plenty of headroom  for reliability.

The Unico 150 will be available in the UK from November 2015.

It will be available in Silver finish, or to special order in Black for a £100.00 surcharge.

SRP £4,000.00

The Collatio OTL Series is a special project, and is Aries Cerat’s statement on how they think a true SOTA OTL amplifier should sound.

The Collatio II istheir showcase, a statement, a cost no object approach on OTL tube amplification, “pushing the envelope on what is possible on OTL technology”.

The Collatio II amplifieruses aproprietary design, and it is in fact a current amplifier which “have their own technical and sonic advantages, and if especially matched with highly efficient horn speakers, are simply unmatched”.

The output stage is a “unique Single ended stage”, a parallel-feed power stage, using 20 power tubes in parallel per channel, loaded by 4 massive chokes, and AC coupled to the output terminals, using an exotic film capacitor.

The capacitor is designed to be able to surge 20.000A peaks, and it’s ESR and ESL specifications, are an “order of magnitude lower than any audio capacitor, film or electrolytic”.

This power tubes used is the 6c19p, a small envelope tube,  a very low internal resistance tube, capable of large current swings and was “much preferred over the usual OTL tube candidates in terms of bass slam and timbre”. Also it is very cheap tube to replace.
The tube bank is biased at 2.6A per channel(20W) and at 5.2A for the 80W version! The output stage is a true single ended power gain stage and thus can only operate in Class A. No global or local feedback is used.

The power supply provides 2.6A per channel steady state and the double output stage power supplies, come with double choke filtration and 6 high current high speed capacitors.

The driving stage, is a Directly Heated triode, the 814 tube, a big bottle tube that can deliver 10W of driving power to the output stage.

Driving 20 output tubes per channel at high frequency needs a lot of current, and the 814 tube has a lot to spare. The driver tube is chple loaded, and  is DC coupled to the output stage,for supreme slew rate numbers and transparency. The driver stage power supply I s fed by separate transformers and is double filtered using chokes.

All heater and filament supplies have their own power transformer and are douple filtered using chokes and high speed capacitors.

Most OTL have a bad reputation of blowing expensive speakers,after they present DC potential after a malfunction. “The Collatio amplifiers are bullet proof in terms of stability and speaker protection.” Their output stage is AC coupled, so that no DC can be present at any times at the speaker terminal.

The Collatio 20W stereo amplifiers can be used as monoblocks, delivering 80W of OTL SE power with no modification from the user.

Specifications

Full power bandwidth: 6Hz-110KHz

Small signal bandwidth: 4Hz-110KHz

SNR: 110db

Gain: X6 ( 15db)

Full power:  20W @8ohm

80W @8ohm mono configuration

Current idle per channel: 2.6A

Idle power consumption: 1190W(depending on bias level)

Dimenisons:    455mmW  X 590mmD X 480mmH (excluding tubes+cage)

455mmW  X 590mmD X 630mmH including tube cage

Weight: 120kg

Tube compliment: 2 X 814 , 40 X 6c19p-v

After 40 years of creating audio equipment, the last thing that artist-designer Kostas Metaxas wanted to produce was “another box with transistors on a heatsink”. He was apparently inspired by ‘the most spectacular architecture, design and sculpture’ he had experienced and ‘wanted to bring that emotional intensity, daring and seductive beauty to an audio amplifier.’

The Solitaire 2016 is the result. Machined from a solid block of either aircraft aluminium, copper or titanium, it’s totally bespoke and Metawas claims that ‘the modular electronics make it future-proof’. Even the circuit boards are CNC machined from 1mm solid silver coated clear polystyrene.  100% designed and engineered by Kostas Metaxas, each amplifier is assembled by his sons, either Andreas or Alessandros Metaxas.

The Solitaire 2016 along with the Ikarus Integrated Amplifier and Opus preamplifier will be “world premiered” at the Munich High End Hifi Show in May 2016. A Studer A80 will be playing 10″ Analogue Master Tapes from a selection of the over 300 Classical and Jazz concerts recorded by Metaxas on his modified Stellavox Tape equipment. Hifi Pig will be there to report back on how they sound.

Janine Elliot takes a step down memory lane with the much loved Leak Stereo 20 power amplifier. 

If I had to select one item I have I my collection from the past century that made the earliest and biggest impact in the hifi industry 50 years later, it would have to be my Leak Stereo 20 and matching preamp. I still love the sound, though have considerably modified it, whilst leaving its beautiful capacitor cases intact.

Introduced in April 1958 at the Audio Fair in London, just weeks after the first stereo LP hit the platter, it originally appeared in Champagne Gold, which soon changed to Gold Bronze, the colour of mine, and later in 1964 a boring dark grey colour. The original price of 29 guineas plus a further 20 for the partnering Point One stereo preamp, was quite a hefty outlay when the average monthly salary was only four pounds more. The history of Harold Leak’s company, H.J. Leak & Co. Ltd, from its original offices in 470 Uxbridge Road, London, W12, is quite a major one in terms of audio. Leak revolutionised the performance standards of amplifiers way back in June 1945, when, as a result of his research, he transformed amplifier distortion down from an average of 3-4% to an unprecedented 0.1%. Consequently all his products were labelled Point One. His world-beating amplifier designs gave Leak a world-wide reputation.

The Leak Stereo 20 is therefore actually called the “Point One Stereo 20” denoting the fact that as well as the 0.1% harmonic distortion, 20 watts is had by both channels (10 + 10 Watts). It carries on from the slightly earlier and similar design TL12 Plus (1957), having identical output stages, with EL84’s, though using two ECC83’s instead of EF86 and ECC81 in the driver stage of the design. The GZ34 rectifier is used in both designs. The much earlier original TL12 from 1949 had much bigger bottle valves, and this model was highly successful, with sales to the BBC, Swiss Broadcasting Corporation and the Italian Broadcasting Corporation. Over 2000 units were sold to America in the first 5 months, an enviable reputation from a fledgling British company. What really made the Stereo 20 amplifier special for me was the clever safety design built in to protect it from overloading. A 100Ω/3W resistor is soldered upside down at the front of the unit, and bearing in mind that with the amplifier operating normally (ie, capacitors and valves in good condition), this resistor dissipates two-and-a-half watts and therefore runs pretty hot. If a coupling capacitor fails and it then puts a positive voltage onto the control grid of the output valve, it will pass more current and may eventually go virtual short circuit. This means the resistor will get extremely hot and will de-solder itself from the connector and drops off, protecting the transformers. I was given a faulty Leak Stereo 20, which had quite simply protected itself at some point, so all I needed to do was re-solder it back and start listening! So, if you get offered a faulty Leak, check this safety point. I changed all the capacitors and valves on my Leak, and only needed to change some of the resistors and clean the joints on my Varislope preamp to get the pair working again in harmony.

And sound good it certainly does, with a typical bass and treble warmth and roll off typical of valve amplifiers from this period, though it has a great mid-band making for great vocals and strings. The quoted frequency response is 20-20,000Hz+/-0.5dB, so it is still very acceptable. The pre-amp is the weakest link, though has a considerable number of listening options and settings in the VariSlope Stereo version from 1960, similar to the original Point One from 1958. Despite a 0.01% total harmonic distortion and three input sensitivities its output S/N ratio was 52dB for moving magnet phono and only 60dB for line (compared with 80dB for the Stereo 20 power-amp). The Leak VariSlope pre-amplifiers (they started in 1952 in mono form) were designed to slope the high frequency output to enable the high-frequency distortion from inadequate disc reproduction of the day to be filtered out – with minimal effect on the audio signal itself. Like other Leak pre-amps, and most audio of its day, it was designed to be mounted in a timber cabinet, and all looked magnificent and quite modern even today, certainly in the gold bronze, flat fronted models. Indeed, the earlier incarnations looked more modern than the later “Varislope Stereo” (1960) in its curved burgundy red and gold ‘plasticky’ front. Just as early cars were bought in basic form and you sent it to a coach builder to make the bodywork and seats, so early hifi was often bought in the “nude” for you to make the cabinets. As well as a number of versions appearing of this preamplifier, so did later models of the power amp. As the “20” went to production, a “50” appeared with 25 Watts per channel and in 1964 the “60” with its 30 Watts per channel (both with EL34’s instead of EL84’s output valves). Neither of these models was as iconic as the 20. 

In 1963 Harold Leak moved to integrated amplifiers with the transistor Stereo 30, and in 1968 with the Stereo 70 with yes you guessed, 35 Watts per channel. Both failed as products and proved to Harold that Valve worked best. In common with even his earlier TL12, TL25 and TL50 mono amplifier, the bigger output they offered, the worse the sound. Therefore the best models to buy would be the stereo 20 followed by the TL12.

Back to the Stereo 20, I use mine with the minimalist Meridian 101 preamplifier, a combination that today would easily pass as a £1000 offering, and the much higher output from the 101 does not give the Stereo 20 any problems; the 10 Watts per channel is no slouch up against my Krell 250W goliaths. The original VariSlope and Point One preamps were designed for tape outputs, and not modern-day digital players, and so they are very low level, and the sound quality does not match that of the power-amp.

Would I recommend you finding a Leak on eBay? Of course I would, and if you could find the earliest champagne gold version, then snap it up whatever the condition, as they are very rare objects. With all models, check the underside for large amounts of wax which may have run out of the transformer if it’s been overheating. The mains transformer, as I mentioned earlier, can be problematic, though the safety resistor should have done its job well. Like all old things, they start to leak and so the capacitors will most definitely need changing, but whatever you do, don’t disassemble the two original “can” electrolytic capacitors visible in line with the valves, as the Stereo 20 won’t look the job anymore, and certainly not be worth as much. What I did originally was disconnect them and use tiny switch-mode power supply capacitors (47uF, 400V) which I strapped onto the underside of the original valves. Whilst this doesn’t look very nice, it is underneath so only flies and spiders would see it anyway. I have now modded my Leak even further to set it to the next level.

To the sound, whilst slow and imprecise by today’s standard, is very musical and therefore enjoyable, particularly on vocal and orchestral music. It even tries its best on pop and passes quite admirably, though if it had its own mind of 1958 I wonder what it would think of it all. The Stereo 20 was the pinnacle of Harold Leak’s work, and luckily still keep his reputation sound (sic) today. I remember his later products, such as the Sandwich speakers and the time delay compensated 3050’s speakers sitting in Lasky’s in Tottenham Road, London, and whilst these were iconic inventions, are not the first thing you think of when you mention his name. Leak was a great name, and if only someone would revive the brand again, just as they have iconic cars such as Mini, Fiat 500 and VW Beetle, I wonder what it would sound and look like. Not that this hasn’t been done before. Audio Innovations begat Audion and AudioNote of Japan, as have many other manufacturers rebranded or bought into old names. Some manufacturers like Transcriptors claim to have re-appeared again, and of course some present-day manufacturers have even re-released old models, like Quad II, and even famous Musical Fidelity A1 integrated amplifier of the 1984 was reborn by them twenty years later. Best, perhaps, that we just add some TLC on the original TL and Stereo 20 and just bring them back to life again in our own homes by ourselves.

Janine Elliot

UK importer Hidden Systems has been in touch to tell us about the continued success they are having with the Lejonklou range of  phono stages, preamps and power amps, which we at Hifi Pig had not come across previously.

The brand is designed by Frederick Lejonklou and he says “Building the best Hifi is like building a musical instrument. Every detail matters. While a lot of companies like to claim they pay attention to detail, we mean it in an extreme way.”

The Lejonklou range includes:

Sagatun Preamplifier

Sagatun Mono Preamplifier (Pictured)

Tundra Stereo Power Amplifier

Tundra Mono Power Amplifier

Gaio MM Phono Stage

Slipsik MM Reference Phono Stage

Audio Research say they are pleased to announce that the GSi75 integrated amplifier, the third member of the G-Series, is finally a reality and in production. First shown as a prototype at  the Munich High End show in 2014 (And very nice it looked too), the final production version has grown in size, versatility, and performance with Audio Research calling it the Swiss army knife in their lineup.

The GSi75 is more than a simple integrated amplifier, it is a one-box solution that includes both a high per- formance DAC and phono stage; all you need is a digital source, a turntable, and speakers…it even has a tube headphone section.

The DAC in the GSi75 is the companyy’s most advanced design, handling digital sampling rates up to 384kHz and DSD 1x and 2x, in both native and DoP formats via USB 2.0. True, native DSD bitstreams are resolved with no PCM conversion. In addition to the USB input, the GSi75 also has Toslink and RCA inputs. Fast and Slow filters are selectable, as is Upsampling to 352kHz or 384kHz. A separate driver is not required for Mac.

The phono section has switchable 45dB or 62dB gain for use with MM or MC cartridges. Input impedance is selectable (47k, 1000k, 500, 200 or 100 ohms) via the front panel or the remote.

In addition to the digital and phono inputs, there are three other SE inputs, one of which can be configured as a home theater pass- through. The GSi75 has an IR input, and is also controllable via RS-232. The GSi75 has two 6H30 driver tubes and four KT150 output tubes that should last 3,000 hours. There are 4 and 8ohm speaker outputs.

“The GSi75 is a sonic knockout, with clarity, dynamics and the same engaging immediacy that you have come to expect from the GSPre and GS150” say the company. Visually, it has the same elegant esthetic as its siblings, featuring a welded, hand-finished, brushed aluminum chassis, matte black transformer cover, black side handles, and a remov- able (perforated black) tube cage.