Product: Gaincard 4706 amplifier
Manufacturer: 47 Labs
Approximate price: e3300
Test sample: loaned from manufacturer
Reviewer: Werner Ogiers
At the beginning of this year I got fascinated by the glowing reports on that funny little sand-based amp, the 47 Labs Gaincard. Since low-powered amplifiers with high-end ambitions simply have to pass the test of making nice noises with the old Quad electrostatic loudspeaker, I decided I was obliged to try and get my hands on a Gaincard. Inquiry at Sakura Systems, USA, however, revealed that our own Geoff already had gotten there before me. Tough luck.
No. Good fortune! Geoff arranged with Sead Lejlic of Konus Audio, distributor in Bosnia and Herzegovina (the world really is getting a small place, hence everyone's interest in a small amp!) and formal owner of TNT's Gaincard demo sample, that the little box could come to Belgium after he was done with it. But more. We needed a short break, and already had decided on the Normandian and Breton coasts for that.
1 + 1 = 2, which lead us through the land of Celts and to the front door of the Husbands.
We had the chance of auditioning the Gaincard at Geoff's place, over a two days time, and combined with some leasure biking. And I agree with Geoff's findings. With the ultra-efficient Cabasse Sloop speakers the little 47 Labs box played incredibly dynamic and lively, while keeping things subtle and detailed as well. When confronted with an unfamiliar system or room my poor brain initially doesn't decode image depth and such well, but at the second day there was plenty of depth, and there was a wide soundstage, and there was sheer realism, this courtesy of some excellent 1950s recordings replayed on a turntable costing more than our new Ford Fiesta.
Reverting to the Audion valve amplifiers we all found that there wasn't much difference with the transistor Gaincard. However, substituting then the big IPL transmissionline speaker for the Cabasses, I firmly preferred the newer, warmer sound, but that is because I really don't like a forward midrange, as generated by the Sloops. Still, apart from tonal balance, the combination of Michell Orbe with Dynavector cartridge and head-amp, Audion pre, Gaincard, 47 Labs wiring, and Cabasses did sound truly special. (As an aside, let me remark that those IPL kits are awesome too, playing in the multi-1000-Euro league!)
I then took the Gaincard to a friend of mine, a dealer, distributor and music lover. I had specified a system to be set-up there in advance, comprising of a Orbe/SME V/Allaerts MC-1, Delphini, Orca, Alecto Stereo, and B&W Nautilus 802s. I wanted the 802s as they are 92dB sensitive, and I've heard them before do nice things with the puny 12W of the Synthesis Nimis tube amp.
Now what surfaced in the end was not quite what the doctor ordered. A prospective customer needed a demo of another big turntable later that day, and so the Orbe remained in the mothballs. Normally this would have been fine with me, but that unnamed other record player so embarassed itself that we had to fall back to a CD-player to get any decent sound at all: out with a Musical Fidelity A3CD. Oh, and the speakers were Nautili 803, at 90dB sensitivity.
With the CD-player directly connected to the Gaincard and things suitable warmed up, one problem was immediately obvious: S'es and sibilants lacked all control and ricochetted between the two speakers like a game of ping-pong. Could it be that the CD-player did not like the fairly low 20kOhms input impedance of the 47 Labs? Insertion of the Orca linestage cured this problem and from now on treble was as pure as possible (given the source).
All present agreed then that the Gaincard emitted very nice and musical sounds, and often reference was made to typically tube-like dynamics (or lack thereof) but with a lot of depth and subtility. Yet, my host wasn't fully convinced, and some switching between the guest amp and a cheaper yet more muscular 70W class AB power amp followed. The verdict that emerged was that while the big-one had a slight sheen colouring its proceedings, and the Gaincard was very similarly off in the other direction, being a bit greyish, the unnamed big-one exerted more control in the bass, sounded a fuller, was more lively overall, and yet did not lose out against the Gaincard in the subtlety department.
Yes, we got good sounds with the 47 Labs, but we had to include a preamp to get there, and moreover a cheaper power amp in residence did even better.
I should have known better. The B&W 803s may have a nominal impedance of 8 Ohms, I actually also know that between 100Hz and 300Hz they have a serious depression to only 3 Ohms. Small wonder that a tiny amp sounds a bit thin...
While the operational amplifier, or opamp, an integrated circuit with tens of transistors offering a near-infinite differential gain, has been used in preamplifier duties for decades now, the so-called power opamp still is a relatively rare animal in quality audio, targeted as it is at boom-boxes and car stereo sets.
In fact I only know of one mid-class integrated amplifier that uses power chips: the Linn Majik-I. And while not bad, this one certainly is not stellar.
But then there are three power opamp exponents in the high-end. From the USA comes the Rowland Concentra, a big integrated amplifier with a reputation, and with 12 LM3886s in a tripled bridge configuration. From Japan, country of the rising sun and of audio extremes, we first had the battery-powered Final power amp (with LM1875 if I'm not mistaken), and now there is of course the 47 Labs Gaincard.
The major drawback of using a power opamp as single active element in a power amplifier is that its topology and design particulars all have been fixed at once, and have been so by the chip designer, not by the audio amplifier designer. Moreover, chip technologies do not permit the use of optimised processes for each type of transistor: i.e. even at the lowest implementation levels exist some compromises a designer using discrete parts is not hindered by.
Against this goes Junji Kimura's rationale: opamps are physically small and thus permit to build a circuit that is tiny, compared to traditional amps. And in a tiny circuit the precious signal does not have to travel over any distances. Compare this to for instance a Krell KAS-2, where the signal path is spread out over several square feet of circuitry.
My turntable was non-operational due to some surgery - I am fitting an SME IV tonearm, and what with the phonostage in desintegrated state? - so the listening was to be done with CD only. I used the fine Hawk MP-DAC, which I expected to complement the Gaincard well, with its warmish and lush sound. It did.
After three days of continuous warm-up the 47 Labs amp yielded a very transparent sound that laid bare everything going on in the music, and this without grain, without trace of electronic artifice. The soundstage was exemplary, wide, deep, and open, this to a degree I hadn't experienced before at home.
Tonally it was light, with a fierce but clean treble and a lean bass. A very interesting bass: what it was lacking in weight and warmth it made up with well-defined contours and a remarkable tightness. Compared to this presentation my usual electronics seem to have a terrible overhang. Or should that be hangover?
Still, I did miss some body in the music, some bloom. Likewise, dynamically there wasn't much push, and for instance my antique Dynaco delivers just that: warmth, kick, and a lush bloom. This exemplifies that the Gaincard electrically may behave as a low-power triode amp, but sonically it is completely different. It is just as flawed as a little tube thing, but then again, it can be just as captivating, only in an entirely different fashion.
You see, while lightweight and pastel-hued, the sound had lots of musical interest. The flow of music, vocal inflections, subtle shadings, the complexity of rhythms, ... all were brought out in an impressive way. No, make that in a beguiling way.
After a while I found a method to partly offset the lightness of touch, the lack of grunt: for each and every recording one specific listening level 'clicked', made things sound more correct, more real than other levels. And when this particular level was within reach of the Gaincard, then bliss resulted. When the level needed was too high for the little amp, then all one could do was put back the disc, or move into a smaller room. This happened quite often, so my conclusion is that the Quad ESL can be a good speaker for the Gaincard, but probably so only in rooms smaller than our 4 x 8 meters.
So far I have not exactly been raving about the Gaincard. What then with all those extatic US reviews??? Let's have a closer look at them: Herb Reichert used the 4706 with Avantgarde Duo horns, Art Dudley (Listener Magazine) with Lowthers. Both highly sensitive designs that can strip wallpaper with only 2 Volts input. A far cry from Nautili or electrostatics indeed. And both reviewers commented on a certain dryness, and lack of a moist atmosphere. Indeed, again. Both found the music recreated through the Gaincard interesting and fun. Dr.Gizmo used Tannoys, and apart from stating that this was the transistor amp he likes most, while still not matching directly-'eated-riodes, he says nothing about the sound. Steven Rochlin gives it 95 points all over the band, but only 75 for sub-bass and 85 for mid-bass. Valerie-Anna-Log comments on a broad and deep soundscape, with plenty of detail and focus. Blair Rogers used Quad 63s, initially did not like it, and after a few weeks said that "if you were looking for tube sound, then look somewhere else, otherwise sit back and and let the 47 weave its delicate spell of silken thread". Ow, he also heard "deep, shuddering bass".
Apparently my own notions about dryness, lack of bass volume, and excellent detail and spaciousness are not far off the mark, and I should not fear being visited by a Ninja hit squad.
Fine. Excellent. Let's continue.
At the beginning of the year I learned that the Synthese One, a legendary Belgian high-end loudspeaker from the eighties, was to be revived in an all-new version. And almost by coincidence I found someone who had just acquired a mint pair of the original Ones. With a benign impedance and a 89dB sensitivity these large four-way transmission lines promised to be a good match for the Gaincard. More: the owner of these speakers expressed an interest in the 47Labs amp. So I did something I normally don't: perform part of a listening test in an alien environment. I hope you'll forgive me.
Again plagued by bad luck, none of my host's turntables were spinnable that night and so we reverted to a big Sony DVD player as source, piped directly into the Gaincard. I only spent a few hours there, so the following comments have anecdotal value at the best. The overall sound reminded me a bit of the Cabasse/47 Labs combination, only now sublimely neutral and with a tight and very deep bass. Dynamics were excellent too, and the Synthese speakers (I hope to review the MkIIs soon) proved to be very transparent, with fine width and depth. I still found things a bit dry and bright, but keep in mind that I was in a strange room, one without much damping at that, and with a speaker I'd never consciously heard before. Nevertheless, a fine result was obvious, and the Syntheses clearly mated well with the Gaincard.
In the following days my host played on with this system, augmented now by a Pioneer CL-590/Dynavector DV-505/Shure V-15 vinyl setup (big Japanese direct-drive battleship of the sort Thorsten would approve of). He liked the Gaincard a lot with vinyl, commenting favourably on its precision. Conversely, the revealing nature of the little amp was too much for his poor Sony DVD and Rega Planet CD-player. Still, a decision to buy the 4706 followed soon after.
And the story doesn't end here. I got contacted by another Belgian loudspeaker manufacturer, Koen Vaessen, of $10000 Aquarius fame, and after having listened to the Gaincard on his own designs, again very efficient wide-band speakers, he took up the distribution for the Benelux countries.
I admire the Gaincard, simply for proving that an awful lot of good noises can be made with just a pair of cheap power opamps. It proves something that is highly relevant to audio design. I adore its concept and the package it comes in. However, I do not love it, because to me (and in my system and with cabling that, I admit, did it injustice) the lack of bass and warmth moved it too far away from my tastes. In addition, its scope of application is rather limited: loudspeaker choice is critical, and not all sources are prepared to drive the Gaincard directly, without preamp (I experienced problems with two or three other sources). Then again, when things 'click' the Gaincard really is an effective integrated amplifier, and at no time did I find the twelve-step dual-mono attenuators a nuisance or an inconvenience.
Wrapping it up, 47may not be the answer to everything (we all actually know that 42 is the real number ;-). But if you have wide-bandwidth speakers of high-efficiency and with a generous bottom end, coupled with a warm yet transparent source, then be my guest, for, when all is said and done, the Gaincard remains something truly special.
And Sead, man, do you have any idea how curious I'm now about the 4712 phonocube? Any idea?
This was a laborious review, and without the help from Sead Lejlic (Konus Audio), Geoff Husband (TNT), Philip Matthews (Hifi Corner), and Henk Catry, it would never have happened. So, thanks guys!
© Copyright 2000 Werner Ogiers for TNT Audio Magazine (https://www.tnt-audio.com)