Products: Quest Silver 300b SE monoblocks and M3 preamp
Manufacturer: Audio Note UK - UK
Cost: Quest Silver: 6200 €, M3: 6700 €
Reviewer: Geoff Husband - TNT France
Reviewed: October, 2003
Regular readers will know that for nearly two years now my main speakers have been a pair of Loth-x Polaris Horns. These have for the most part been powered by my Audion Silver Knight 2.0 pre and ETPP EL34 30 watt monoblocks. These amps have never let me down and made the transition from averagely efficient transmission-lines to the horns without a hitch.
But the Polaris probably never draw more than a watt (they are 104 dB efficient) and were designed to partner a single ended 300b amp. The upshot was that inevitably I needed to know what the Polaris could do when driven by their natural partner and so organised the Loth-x Ji-300b amp for review. The results were some captivating moments but a resolutely mid-forward balance that I really found too wearing with the majority of my flawed record collection. It seemed to me that far from being an ideal match the Ji-300b was in fact a missmatch with the Polaris. This view was confirmed recently when I learnt that Loth-x have redesigned the Polaris driver by removing the whizzer cone, a change which will reduce the mid/upper output of the Polaris considerably. I suspect (and hopefully I will have the new driver soon to see) that the current speaker is now a much better match for the Ji-300, but that of course doesn't help me :-)
There followed the review of the Son of Pharao, a sophisticated EL34 based 40 watt amp which produced a far more balanced presentation, even better than my Audions and I began to think that the Polaris, as I had them, were not the match for the 300b valve they were cracked up to be.
But curiosity continued and so currently in my living room are three other 300b single ended amps and all show a fine balance with the Polaris, the subject of this review, the Audio Note Quest Silver and M3, being the first to arrive, get centre stage before the others :-)
The M3 is a "classic" looking pre-amp. A big bluff box in black painted steel with a thick aluminium faceplate and knobs, weighing in at 36 lbs. It's very well put together but it isn't going to turn heads. Though not over endowed with bells and whistles such as remotes and displays, it's actually a well-specified pre by audiophile standards with a phono input, four line inputs and tape. There are balanced outputs and two pairs of phono outs, so for most stereo enthusiasts it offers all you could want. Unusually it sports a balance control which offers gentle correction of balance, not something I used, but many rooms give an off centre hot-spot and sometimes recordings, or indeed sources are biased one way so the control can be useful. These controls are all made by Noble.
Inside the amp shows where the money and originality has gone. Dual mono, choked power supplies and an array of coupling transformers fill the large case, this use of transformers is at the heart of the design. The circuit is a zero feedback using 5687 valves. The optional phono stage is again zero feedback and is passive. The whole thing is hand/hard wired with the usual AN dusting of Cerafine and Black Gate capacitors. Lastly the AN output transformer is IE cored.
The Quest Silvers are a natural partner to the M3, and are an upgraded version of the Quest monoblocks, the changes being better capacitors, and a superior C-cored output transformer. Other than that it shares the same basic design (they look identical) with a pair of 300b's flanked by a 6SN7 doing duty as a driver and input stage and a 5U4G doing the rectification. Output is claimed to be fractionally up on the standard Quest's 9 watts due to the better transformer, but to be honest that aspect wasn't going to be an issue, the Polaris's efficiency making 10 watts approximately equivelent to a 200 watt amp driving 90 dbl efficient speakers - food for thought...
The chassis is again a hefty steel affair in black as are the transformer covers. By heafty I mean you could throw the thing from a second floor window and the actual main case would be undented (no I didn't try it). Cosmetic touches are the copper top-plate and the small piano-black front plate. I actually think they look classy without being flashy - YMMV. At nearly 30 lbs each I was glad they were monoblocks, and their slim but deep build meant they would only fit on a standard rack sideways.
At this point my technical knowledge is exhausted (and then some) but Peter Qvortrup has kindly produced a short note at the end of the review.
First the moans. The power amps hissed and had a hint of hum. Peter believes that to get the best from the amps they need to have very high gain. AN's own speakers are only (!) around 95dbl efficient so the noise isn't anything like as much of a problem. This noise was barely audible in the listening room from the listening position, and at no time did it bother me or become apparent in use. This noise also varied with the 300b's in use, the French distributors favourite JJ's being particularly quiet, TJ mesh plates were plagued with hum. The amps also seemed relatively immune to mains buzz etc, something which haunted the Ji300b on bad nights. Overall the Quests are quiet by SE standards if not that set by my old Audion push-pulls. Secondly the preamp puts out over 4 v which meant that the volume control was only useable over the first 1/4 of its travel. Again this wasn't a problem, and of course the Polaris were at least partly responsible. Lastly of the five 300b amps I've had here recently these are the only ones which will accept the valve pins the wrong way round - you've been warned.
Firing up the amps for the first time I was greeted by a presentation not a million miles from the Ji300, amazing mid-band but a bit pushy and forced. Unlike the Ji300 the AN's proceeded, over the next week to settle down to an overall balance very much like my old Audions - fuller, more weighty and much better balanced all round. Of course this made them very nice to sit in front of, my system and ears being optimised for the old balance. In fact with many records and blind, I'd be pushed to tell them apart. Which of course is great until you note that the AN's are over twice the price of the Audions.
Then a few things changed. I found I was playing a lot of music, always a good sign. I just felt so at home and happy with the presentation, it seemed to be making the most of both good and bad recordings. Remember I praised the Ji300b for making 5% of my records sound amazing, well the AN made all listenable, some excellent, but that same 5% astonishing. The combination did everything the JI300b did but endowed it with such balance, grace and poise. Beyond this the realisation that something special was happening came with records that were very familiar.
You're all going to hate this, but it's back to Simply Red's 'Sad Old Red' :-)
If you go back to my 'Elevator' review you'll read "The change of pace and the heavier strike on the cymbal that happen midway through the song was beautifully handled, the increased dynamic range effortless". Err... Not... With the M3 and Quests I realised with a jolt that I was hearing a whole level of complexity and tonal accuracy. The drummer doesn't use a heavier strike on the cymbal. What actually happens is that for the first half of the track he is playing a large ride cymbal with a metal (not plastic) brush - I'd even hazard a guess that it's a flattened one with quite short wires. He then moves (and the spatial information is explicit) from the ride to where a traditional crash cymbal should be and changes to a light drumstick and plays the smaller cymbal close to the bell. Now I have a similar set up here (my son's) and can replicate the change, his 'crash' ( a Sabian AAX 17" Stage Crash) has a similar sweet bell and can likewise be ridden beautifully.
Now that is a huge increase in ability, concentrated on just about every aspect of musical reproduction, tonal accuracy, soundstaging, speed, definition and just good old-fashioned detail...
Because I thought I knew this track's every nuance it made the transition so startling. More and more I found myself appreciating what a musician was trying to do and thus was dragged further into the music. And this wasn't some academic exercise, it made reading with music in the background impossible it just kept drawing me in. This applied with mono recordings from the 50's like Nina Simone right up to audiophile pressings.
Another example. Joe Jackson's 'Body and Soul' has been praised by Scott as a wonderful audiophile, and yet mainstream recording. Here it sounded rather forced and unnatural, with that weak 'airy' artificiality that so often passes for fidelity these days. With the AN's I suddenly saw what Scott was on about. It's an amazing recording, the drumkit miles back in the acoustic of the ancient masonic lodge that it was recorded in. But more than this, oh so much more, I actually started to like the music. Being (again) drawn into it, to feel the interplay between the players.
The effortless speed and coherence made even heavy metal hang together, dynamics of both the Led Zep and Rodrigo kind equally dramatic. The insight picked out recording glitches that made me smile - the clumsy edit at the end of the first verse of "Roksan'", a track I've lived with for 23 years, made me laugh out loud.
Now here I'll be honest and say that the vast majority of people entering my house, including me if I wasn't listening carefully, would find no increase in sound quality over the Audions. And yet something fundamental was happening once you sat down and listened. The plain truth is that the AN's just gave you more music - not specifically an increase in some hi-fi aspect (though they did that too) but a real feeling of hearing what the musicians were trying to do. This is a 'musical' amp - plain and simple.
As for what is responsible for what? If I was giving credit I'd say 60% preamp 40% power, the Quest silvers are good, but the M3 is spectacular. In fact it reminded me a little of the Korato pre in it's opening up of events in time and space, the physical space between players and the distance between notes in time. But it's tonal attributes went beyond the Korato so that though ruthlessly revealing it never pushed the Polaris into information overload, the combination always easy to listen too.
We move on a couple of weeks. My mate Steve flies over for a weekend long orgy of music and hi-fi. He's wondering in what direction to go in the future with his hi-fi. He's always loved my Audions and one reason for the weekend was to check out the amps I had here. He, like myself, was very, very impressed with the "Son of Pharao" and it would have driven his speakers. Then I put on the Audio Notes and his face fell, because what he heard then was magic - "it's got to be single-ended then"... Despite the much more difficult path that he'd now have to take re changing speakers he knew that he would always miss what he'd heard that day. And yet the difference between that very worthy 40 watt amp and the 9 watt Audio Note's was by any rational measure tiny - thus it is that we addicts are drawn into such folly.
The Audio Note pairing is hideously expensive, there are amps out there that do 90% of what they do for less than 1/2 the price. But the 10% is very, very tough to live without once you've heard it. And there's the rub, because they're staying here. Not only did they outperform my old Audions but in purely sonic terms the power amps had a healthy lead over the other two 300b powered amps that have passed through here in the last two months, i.e. the Audion Silver Knight PSE and Wavac MD 300B, both worthy designs in their own right., but no regrets...
When we came to look at designing a true reference quality pre-amplifier we discarded most fashionable notions about what constitutes good design and went back to basics in the most "basic" sense of the word.
A clean sheet of paper
Having spent a few years studying the use of interface transformers in a number of applications (notably in the I/V conversion in D to A converters and the matching of moving coil cartridges, where active circuits are normally used) we came to the conclusion that a transformer coupled pre-amplifier design would be a significant advance in quality compared to anything available at the time (1995).
The design work that created the M3 pre-amplifier and it's later and more sophisticated siblings, the M5, M6 and M8 is the culmination of several years research and design work and represents a genuine breakthrough in small signal amplification and are masterpieces of elegant simplicity.
The M3Phono uses a 33:1 step down ratio output transformer, this transformer is driven by a very powerful line stage consisting of one 5687 double triode per channel coupled as a series anode follower.
The phono stage uses a one 6072A double triode as the first stage and another 6072 as a second stage with the RIAA equaliser being entirely passive.
The power supply is essentially an LCLC network with high voltage rectification being performed by a 6X5 valve rectifier, it is mono throughout, with 2 mains transformers (one per channel) and 4 chokes (2 per channel), which explains the weight of the M3.
The Quest Silver 300B Mono Power amplifiers
Compact size with high quality was the aim with the "compact series" of 300B amplifiers, simple, good quality no feedback circuitry with good components yield a better than average sound.
The Quest Silver features all the basic elements that makes a good single-ended power amplifier, valve rectified HT supply, 3 amplification stages with no feedback whatsoever, valves that compliment each other's sound and characteristics, 6SN7 - 300B with a 5U4G rectifier valve.
The output transformer is an in-house designed and made part which is massively oversized to allow the 300B output stage to breathe best possible, a massive 50-60 watt core sees to that.
Parts quality in both the M3 and the Quest Silver are of consummate quality, Audio Note™ tantalum resistors, Audio Note™ copper foil in oil signal capacitors and Black Gate and Cerafine electrolytics where they make the most difference.
All in all adhering to the Audio Note philosophy of providing the best possible sonic solution at a given pricepoint, with longevity built-in.
PQ - AudioNote
© Copyright 2003 Geoff Husband - www.tnt-audio.com