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chrismercurio 14th March 2012 05:33 AM

First Watt M2

I know we generally talk about building stuff around here and I'm on the fence about building a 3 stage DHT GM70 amplifier. The M2 would just make life easier. I'm looking for something with the immediacy of SET but the detail, extension and reliability of solid state with enough power to drive a real world speaker. I have "normal" speakers of moderate efficiency and a 4 ohm nominal impedance. Any feedback is very much appreciated.

Hoping to hear from those that own or have heard the M2...


ra7 14th March 2012 03:56 PM

Ohh! And I thought you'd never ask.

The M2 is an amazing amplifier. I would refer you to Srajan's reviews on 6moons for comparisons with the F5 and J2.

First, what it does like good triode amps: smooth Class A sound. Very palpable and real images. Deep soundstage.

And what it does better than tubes: Bass, depth, control. Zero coloration. Once you hear this, you will know that even a good 2A3 adds some coloration, however pleasent it may be. This amp can drill down to the last detail and yet sound accurate, pure and sweet. In fact, I would put detail retrieval better than a 2A3. Little inflexions of voice, small nuances are revealed easily and with a touch of sweetness.

IMO, the M2 is a very niche product, intended for people who crave the sweetness of tubes above all else. If you want just the facts, go with an F5. But you like a little romance, some musical pleasure, the M2 fits the bill. I can't believe how much pleasure this amp is giving me, which I previously thought was possible only with a good SET.

Thanks Papa!

Nelson Pass 16th March 2012 06:57 PM

Thanks for the good review......


6L6 16th March 2012 07:07 PM

Is the real schematic floating around there somewhere? It's an awfully intriguing design... :D :D :D

chrismercurio 16th March 2012 07:10 PM

I think this one is strictly under wraps. He has to keep some of the good stuff for himself. Especially considering how much he shares and how freely he shares it. I need to have one...

Zen Mod 16th March 2012 07:21 PM

I made one iteration , somewhere right after first informations about concept and pics were published on net;

even if it's working (was , dismantled , as usual ) it is pathetic comparing to real McKay .

sound was gorgeous .

unfortunately - can't share , there are still (in it ) some tricks from Papa's sleeve not published , so I can't be first to reveal them


I succeeded in most prominent characteristic of M2 - 90 or something secs slow ramp up of bias


in any case - I certainly gave few mins of good laugh to Papa , when I send him schm of my iteration


ra7 16th March 2012 07:45 PM

Yes, it does take time to warm up. I could swear it sounded better after an hour.

It is also driving a notoriously difficult load right now - B&W683s. Tube amps sound awful driving these speakers. The M2 sings. I measured about 5V on Pano's voltage at the speaker terminal. Just enough volume for me through the DCB1. It takes a good 3.5V to drive it to full power though.

Its dead quiet too. So quiet that you cannot tell if it is on through the speakers. Can't wait to see how it sounds on the big horns.

Zen Mod 16th March 2012 07:57 PM

did you post somewhere some porn of your system ?

regarding time - 1 hour is sort of usual period for A class amps ( at least sand ones )

I was thinking more about things Papa sez to 6moon Srajan :


The bias circuits take a couple of minutes to fully charge but then they settle into high precision. The slow charge is how I avoid that precision from creating any sonic artifacts. The first ones I made took a full 2 minutes before any sound came out at all. You can imagine the messages I got. I should have put something in the manual about it. Something like that's the tubes warming up! Also, as the M2 biases up, the output stage goes from class B to class AB to class A. What you get to listen to is the character of each without feedback. Ontogeny recapitulates philogeny.
that was answer for Srajan's :


A quick check of life upon arrival netted high audible distortion for the M2. That's because I already had signal running when I flicked the power switch.

ra7 16th March 2012 08:55 PM

No, no porn yet. Maybe once the paper horns are ready.

Michael Rothacher 16th March 2012 08:58 PM

I see ra7 has been holding out on us. :)

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