First Watt M2- Now THIS looks interesting

roscoeiii · « **Reply #20 on:** 14 Mar 2012, 08:26 pm »

Whoa. Didn't realize the F4 does 100W in mono. Into what load?

Freo-1 · « **Reply #21 on:** 14 Mar 2012, 08:31 pm »

Quote from: roscoeiii on 14 Mar 2012, 08:26 pm

Whoa. Didn't realize the F4 does 100W in mono. Into what load?

From the First Watt website:

" As a stereo amplifier with single-ended inputs and outputs, it will deliver up to 25 watts into 8 ohms with a damping factor of 40. It will do 50 watts into 4 ohms, and as a mono-block amplifier with parallel inputs and outputs, it will do about 100 watts into 2 ohms. As a mono-block amplifier with balanced inputs and outputs the power output rating is 100 watts into 8 ohms at 1%.

The amplifier operates Class A to 25 watts (50 peak), and the distortion is 2nd and 3rd harmonic in character, rising or declining in proportion to the output power. The amplifier has a direct coupled input and output, with a -0.5 dB rolloff around .1 Hz and 200 KHz. It does a clean square wave at 100 Khz."

Pretty cool, eh?

TomS · « **Reply #22 on:** 14 Mar 2012, 08:33 pm »

F4's are 100w mono into 8 ohms. I built a pair and ran them balanced. They're very nice as long as the preamp can output enough voltage comfortably.

roscoeiii · « **Reply #23 on:** 14 Mar 2012, 08:34 pm »

Damn.

roscoeiii · « **Reply #24 on:** 14 Mar 2012, 08:35 pm »

But needs to be a balanced input for monoblocks?

Freo-1 · « **Reply #25 on:** 14 Mar 2012, 08:36 pm »

Quote from: TomS on 14 Mar 2012, 08:33 pm

F4's are 100w mono into 8 ohms. I built a pair and ran them balanced. They're very nice as long as the preamp can output enough voltage comfortably.

Right. The Pass Labs X2.5 should work quite nicely in the high gain setting.

Well done on building your own, by the way. Papa stated that it was one of his fav sounding amps.

Freo-1 · « **Reply #26 on:** 14 Mar 2012, 08:39 pm »

Quote from: roscoeiii on 14 Mar 2012, 08:35 pm

But needs to be a balanced input for monoblocks?

Yes (for 100W).

Russellc · « **Reply #27 on:** 25 Mar 2012, 06:39 pm »

Quote from: Freo-1 on 3 Mar 2012, 02:48 am

I think it's the other way around. (Depends what one reads).

I'm keen to listen to a J2 as well. The reason I went with the M2 was power output, as it is 40 wpc @ 4 ohms, while the J2 is more like 13W at 4 ohms.

M2 is 40 into 4ohms, according to the Firstwatt site. J2 only 13 into 4 ohms.
M2 is PP, while J2 is SE.

http://www.firstwatt.com/prod.html

Russellc

Freo-1 · « **Reply #28 on:** 27 Sep 2012, 01:11 am »

Thought I would bring this up to date:

After obtaining a Conrad/Johnson clone preamp, decided to try it with the M2, which was on duty in a HT setup.
The take away is that the M2 LOVES a tube preamp. The combo sounds very close to a all tube playback system, with a few minor deltas. The overall sound stage is wide and deep, and 3D. The midrange has a special quality that does remind the listener of a high end SET setup. The bass is tighter than a SET, which is the delta that is noticeable. The C/J clone is a better match for the M2 than the Pass Labs X 2.5. (Back to this synergy issue here.)

I would highly encourage anyone interested in a Low Wattage setup who wants the qualities of a SET playback system, but does not want to fool with the power amp bottles, to give the M2 a listen with a tube preamp. You will be pleasantly surprised.

roscoeiii · « **Reply #29 on:** 27 Sep 2012, 01:59 am »

An M2 arrived from Reno HiFi today, which I will be comparing to my Rogue Stereo 90 during my 10 day trial period that Mark at Reno offers. Details to come.

But to whet the appetite, the preamp is a Musical Fidelity kW (a hybrid design), and the speakers are VonSchweikert VR-4 Gen IIs (91dB, nominally 7 ohms, biwired).

Freo-1 · « **Reply #30 on:** 27 Sep 2012, 04:27 pm »

Quote from: roscoeiii on 27 Sep 2012, 01:59 am

An M2 arrived from Reno HiFi today, which I will be comparing to my Rogue Stereo 90 during my 10 day trial period that Mark at Reno offers. Details to come.

But to whet the appetite, the preamp is a Musical Fidelity kW (a hybrid design), and the speakers are VonSchweikert VR-4 Gen IIs (91dB, nominally 7 ohms, biwired).

Sounds like you are in for a good experience. I have two M2 amps, one for use bi-amped to the center channel speaker, and one for the rear speakers, to go with a XA 30.5 for the mains. They are a great match, and work wonderful together.
The front end is a Modwright Oppo BDP-83 Nuforce, with a Classe SSP-300. The nice thing about the Classe is NO OPAMPS (all discrete for the 7.1 input).

roscoeiii · « **Reply #31 on:** 27 Sep 2012, 04:29 pm »

Yes, Freo-1 I knew you were a fan. Look forward to hearing how it works with these speakers compared to the tubed and higher powered Rogue.

Freo-1 · « **Reply #32 on:** 27 Sep 2012, 04:31 pm »

As long as your speakers are efficient, it should sound outstanding.

roscoeiii · « **Reply #33 on:** 27 Sep 2012, 04:33 pm »

91 dB, so we will see...

Freo-1 · « **Reply #34 on:** 27 Sep 2012, 04:37 pm »

That should work. Is it 91db at 8, 6, or 4 ohm nominal? I tried it with the Cary Silver Oak Model Ones, which are 88 db/w at 6 to 8 ohms (plus a subwoofer), and it worked great. The Cary's were running full range.

roscoeiii · « **Reply #35 on:** 27 Sep 2012, 05:03 pm »

7 Ohm nominal, but my understanding is the bass module is 4 ohm, while the upper is closer to 8. I biwire these, so am not sure how the separate impedance affects things, vs the amp just seeing the nominal 7 ohms.

roscoeiii · « **Reply #36 on:** 28 Sep 2012, 01:42 am »

Well, here goes with first impressions on my VR-4 Gen IIs in a 13x15 room. Listening at between 60-70dB levels, with the amps level-matched with a dB meter:

I don't see the M2 giving me anything that I am not getting with my Rogue Stereo 90 (4 Ohm tap in ultralinear mode, with KT88s). And the Rogue seems to be doing better in the bass (a surprise considering accepted SS vs. tube differences in the bass). But I am also seeing the Rogue shine in terms of air and the notes of the decay. Not that the M2 sounds poor with the Von Schweikerts. It is as if things on the M2 are a bit muted. I am just not drawn into the music in the same way.

And this isn't coming from a hardcore tube fanboy. I have owned a First Watt F1, F2, F3 and F4. And I have had chances to audition in my system an F2J, as well as a clone F5. Though all of these auditions were with far more efficient speakers (Zu Superflys, and DIY speakers with a 12" Common Sense Audio driver).

This is just the first impression, based on the Fleet Foxes' S/T album (which I know inside and out).

And it occurs to me that these thoughts might be in line with Freo-1s suggestion of pairing a tube preamp with the M2s. While my kW preamp is a hybrid, I wouldn't characterize it as particularly tooby (I do oh so love this preamp tho for the detail and oomph it provides).

It always bears repeating that synergy is everything.

More to come.

Freo-1 · « **Reply #37 on:** 28 Sep 2012, 02:21 am »

Totally agree that synergy is everything

As they say in the UK, its "horses for courses"

Is your M2 a demo, or is it new? I have noticed that they do sound better once broken in, and definitely after an hour or so once broken in.

Thanks for the feedback. Please post your impressions as you continue to audition. More than I would like to think, my initial impression of a product often times is not my final impression.

Lastly, I have learned the hard way that an optimal impedance match between the preamp and power amp is essential to evaluate the overall system sound as a whole.

roscoeiii · « **Reply #38 on:** 28 Sep 2012, 03:40 am »

All good points for sure.

The M2 is used, so presumably broken in.

More to come.

Russellc · « **Reply #39 on:** 5 Mar 2016, 07:10 pm »

I just finished my Pass Approved M-2 from a group buy on the Pass forum over on DIYaudio.com. Very nice amp. Also recently built the F-6, another one with a transformer on the amp board. It uses it differently than M-2, which uses the transformer for gain. I also have built the Pass DIY BA-3 power amp, F-5 power amp, BA-3 preamp, B-1 preamp as well as the Diy Pass Pearl 2 Phono preamp.

All of the Pass stuff is dynamite in the sonics category, and not a single piece of it makes any noise or hum. All units are quiet as the grave.
Lots of support on the diyaudio site if anyone is interested.

Most of these amps can be scaled up for more power. I plan on a pair of Balanced BA-3 mono blocks next, they are easily over 100 watts. It should be kept in mind that these are class A amplifiers, and 50 watts is a lot. These amps get HOT, and expensive heatsinking is required

Russellc