[Sonico]

I'm searching for a power amplifier to pair with a McIntosh c712 preamp and Zu Omen Def speakers.
I want it to be melodic and clear (not mellow and round) and with a good soundstage, capable of filling my big living room (12m x 6m) with powerful party levels sound - not necessarily ear splitting levels. 
Nearby I can purchase a First Watt M2, a McIntosh MC7150 or an Ampzilla 2000 (stereo) for a good price.
I cant audition them at home with my system, so besides my personal opinion on the sound at the different shops, what do you have to say regarding these three models? Any of them is better than the others? Better sound? Better reliability?
Any opinions?

[fredgarvin]

I'm searching for a power amplifier to pair with a McIntosh c712 preamp and Zu Omen Def speakers.
I want it to be melodic and clear (not mellow and round) and with a good soundstage, capable of filling my big living room (12m x 6m) with powerful party levels sound - not necessarily ear splitting levels. 
Nearby I can purchase a First Watt M2, a McIntosh MC7150 or an Ampzilla 2000 (stereo) for a good price.
I cant audition them at home with my system, so besides my personal opinion on the sound at the different shops, what do you have to say regarding these three models? Any of them is better than the others? Better sound? Better reliability?
Any opinions?

IIRC, the Omen is a high efficiency, revealing speaker so higher power is not necessary. The Mac pre already is giving you a certain character that works well with high eff, revealing speakers. A little less detail, a bit softer than many others. The first watt, with 25 watts and a resolving but not brutal character, would probably be very nice.

[mick wolfe]

That's a tough call for anyone to make. Just guessing here, but if you listen at fairly loud levels, I'd probably rule out the First Watt. Not much headroom with  25 watts solid state and Zu's ( in my experience) really come alive at higher volumes. The Mac is a natural choice from a synergy standpoint, but that might give you too much Mac flavor. The Ampzilla 2000 is the most intriguing choice. Might give you the synergy you're looking for plus have the greatest headroom / power delivery. Now feel free to take all this with a grain of salt because I'm just speculating.
 

[Mike B.]

I would rule out the First Watt due to the party levels desired at times. It is a fine sounding amp but does not have enough power IMO. My choice without hearing the complete setup would be the Ampzilla 2k

[brj]

I recommend doing some math before you eliminate any of your options.

http://myhometheater.homestead.com/splcalculator.html

At a typical 10 feet listening distance, 25W gets you 108 dB at your listening position with your 101 dB/1W/1m sensitive speakers.  At 108 dB, your party guests will risk hearing damage, much less be able to have a conversation...

[RDavidson]

IIRC, the Omen is a high efficiency, revealing speaker so higher power is not necessary. The Mac pre already is giving you a certain character that works well with high eff, revealing speakers. A little less detail, a bit softer than many others. The first watt, with 25 watts and a resolving but not brutal character, would probably be very nice.

Yes. The M2 is a highly resolving amplifier (like all First Watt amps), BUT is definitely not edgy or bright. Its sound is on the warmer side of neutral but not at all mushy. It'd be a GREAT (if not ideal) match for your Zu speakers. Not to mention, Pass Labs / First Watt / Nelson Pass (himself) offer fantastic customer service.

[OzarkTom]

First Watt is going to give you the best detail, Ampzilla second but overkill wattage for the Zu's, Mac amp the least detail because of the autoformers. Mac will sound mushy, that is how the older ones sounded. Newer Mac amps may not have that problem

It would be nice to hear all three amps on your system to experience the synergy of each one.

[Tyson]

Another First Watt vote. 

[TEA FOR ONE]

I own a First Watt F5. I run it with a pair of Nola Boxer 2's,and a pair of Hornshoppe Great Horned Heils. The FW sounds fantastic with both. Count me in for First Watt.

[FullRangeMan]

I recommend doing some math before you eliminate any of your options.

http://myhometheater.homestead.com/splcalculator.html

At a typical 10 feet listening distance, 25W gets you 108 dB at your listening position with your 101 dB/1W/1m sensitive speakers.  At 108 dB, your party guests will risk hearing damage, much less be able to have a conversation...

SMT party music is low SPL backgorund music imo to dont disturb conversations so a FW F5 will fit very well.

[Folsom]

Peak watts from M2 are higher. Go with the M2.

[Freo-1]

I've had both the MC150 (which is similar to the MC7150), as well as the M2.  Based on the Zu speakers, I would go with the M2.  The M2 should have enough drive for those speakers. 


If you like the idea of a McIntosh, the one to get IMHO is the MC152.  It sounds MUCH better than the MC7150.  The MC152 has been universally praised as one of the best sounding amps out there.   

[RDavidson]

Peak watts from F5 are higher. Go with the F5.

F5 isn't one of the OP's choices, unless he builds one. It is a favorite among builders because it is relatively easy build (compared to some of the other FW designs) and the cost to performance ratio is outstanding.
I would caution, however, that the F5 can be relentless. Nelson has more or less said this himself. It is like a microscope of an amp. If there are issues in your setup and/or recording quality, it WILL let you hear it all. It just has a way of highlighting leading edges which unearths details like none other (good and bad). As those Zu speakers are on the "energetic" and detailed side, the F5 and Zu's (though maybe a nice electrical pairing) could easily be a synergistic mismatch sonically.

[poseidonsvoice]

F5 isn't one of the OP's choices, unless he builds one. It is a favorite among builders because it is relatively easy build (compared to some of the other FW designs) and the cost to performance ratio is outstanding.
I would caution, however, that the F5 can be relentless. Nelson has more or less said this himself. It is like a microscope of an amp. If there are issues in your setup and/or recording quality, it WILL let you hear it all. It just has a way of highlighting leading edges which unearths details like none other (good and bad). As those Zu speakers are on the "energetic" and detailed side, the F5 and Zu's (though maybe a nice electrical pairing) could easily be a synergistic mismatch sonically.

Good points.

Best,
Anand.

[Phil A]

The F5 also doesn't have tons of gain (chart is here - http://www.firstwatt.com/prod.html).  I had a friend who sold it and got a J2.  He liked the sound but the gain wasn't quite enough.

[poseidonsvoice]

The F5 also doesn't have tons of gain (chart is here - http://www.firstwatt.com/prod.html).  I had a friend who sold it and got a J2.  He liked the sound but the gain wasn't quite enough.

Low powered amplifiers whether tube or SS will not have tons of gain by design (ie, they don’t need it and higher gain needlessly increases noise). The important point is to optimize the gain structure of the overall system (source to speakers). With Zu speakers (98-101dB/1w/1m) there is little worry for too little gain. In fact the worry should be too much gain especially with digital sources and their greater than or equal to 2V RMS output voltages.

Best,
Anand.

[Phil A]

My friend's speakers (Reference 3A Taxims) are 92db and 8 ohms.  It was just the combo of his preamp (Copland) and will the volume all the way up on some things it was not quite as loud as he would like it.  So since he liked the sound, I told him to stick to the same family but something will a bit more gain.  He loves the J2.

[maty]

http://www.enjoythemusic.com/magazine/equipment/1211/zu_audio_omen_def_speaker.htm

Sensitivity: 98dB/W/m
Impedance: 6 Ohm nominal

Example: SPL at 80 dB (loud). Playing very good recording with very high Dynamic Range (DR): 17 dB => you need amplifier + speakers: 97 dB.

20 watts Class A amplifier

http://www.doctorproaudio.com/doctor/calculadores_en.htm#calc_spl

SPL calculator

20 watts, random phase

2 m -> 108 dB

3 m -> 104.5 dB

4 m -> 102 dB

5 m -> 100 dB

6 m -> 98.5 dB

7 m -> 97.1 dB

8 m -> 96 dB

distance to each speaker

8 m = 26.2467 feet

[PMAT]

Ampzilla because it's versatile and can power most future speakers or 2nd system speakers. Systems change with time for us semi-tweakers and many configurations benefit from available headroom and drive. Another 2 cents 

[Folsom]

F5 isn't one of the OP's choices, unless he builds one. It is a favorite among builders because it is relatively easy build (compared to some of the other FW designs) and the cost to performance ratio is outstanding.
I would caution, however, that the F5 can be relentless. Nelson has more or less said this himself. It is like a microscope of an amp. If there are issues in your setup and/or recording quality, it WILL let you hear it all. It just has a way of highlighting leading edges which unearths details like none other (good and bad). As those Zu speakers are on the "energetic" and detailed side, the F5 and Zu's (though maybe a nice electrical pairing) could easily be a synergistic mismatch sonically.

Fixed