Any Gainclone or Class D or battery power alternatives available? I like the crazy good micro dynamics and rhythmic cohesion of the J2. My speakers are 93db full range. Also interested in AMP/DAC combinations like the devialet or NAD D7050 that meet the J2 performance (those 2 mentioned don't)
Since you are so happy with it, I would try to make the J2 work somehow. Its not an easy amp to beat. But if you must, see is you can demo an Ayre V5. It does sound different from your Pass, but has a lot of the qualities you are looking for. There's a good chance that you'll like it better.
"I like the crazy good micro dynamics and rhythmic cohesion of the J2."
The Ayre does that better than the J2. It also has more resolution, more power, bigger dynamic contrast and the imaging is incredible. One thing that you may, or may not like about the V5 is that its not quite as forgiving as your current amp. Its probably due to the fact that Pass uses mosfet transistors, and most other amps use bipolar. You may think that's good or bad, depending on your personal preference.
Some other good choices you may want to look at are solid state BAT, Theta and maybe Sim. They're all fully balanced, 0 feedback designs, like your J2.
I would try to adapt to the heat. Is there any way you can sit at a distance that the amp is not annoying you with its heat, or are you concerned about children touching it.
Audio Consulting Mipa. 2x30W. 2 battery. No heat. I have one for sale. It needs a preamplifier with very low output impedance or passive with transformers.
Buy one of those small refrigerators and put the amp inside that. Cut a hole in it for the cables and seal it off with a rubber grommet. Problem solved. Just make sure you run a dedicated line directly to the fridge so its isolated from your system, and don't forget to put cones under it.
Bojack I'm inclined to agree with you. I'd keep the First Watt compared to the other alternatives suggested. Not so sure they will sound better than the F.W. J2.
Just a small correction- the J2 does have negative feedback.
OP: Ayre and DarTZeel are the two A/B amps (cooler) that don't use negative feedback. The latter has a new integrated with built-in DAC which might interest you.
"01-13-15: Keithr Just a small correction- the J2 does have negative feedback."
I didn't know that. I thought all Pass amps were 0 feedback. Thanks for the info.
Talking about Pass amps and heat, I just remembered that one of my Pass amps burst into flames right in my living room. It was actually kind of funny. But not to worry, it was an Aleph, not a Firstwatt. Most likely the problem is fixed in the newer models.
I recently got myself a J2 and they don't get that hot. Less heat than a push pull tube amp. I was very concerned about heat given I live in small NYC apartment. But it's totally manageable. It doesn't heat up my room. Make sure to have the amp in an open space. I can keep my hands on the amp chassis without getting bothered by heat.
According to its manual the J2 consumes 200 watts. Since it operates in class A it will draw that amount of power essentially all of the time it is being operated, regardless of the dynamics of the music. So the amount of heat injected into the room will be approximately the same as the heat produced by two 100 watt light bulbs.
The reason the First Watt sounds like it does is its class A. Class A makes more heat; you're not going to find a cool running amp that is class A, so if you like the sound I would find a way to deal with the heat. Putting it in a refrigerator BTW will not work- the refrigerator has to get rid of the heat and will do so via its heatsink system.
One simple solution is to have a vent placed in the room above the amplifiers locations. The vents are then ducted to a fan that blows the air outside if needed. This system can be very effective and is cheap.
It’s a simple thing to wire a small quiet fan hidden near a hot amp. Years ago I had amps in a closet space and did just that and it worked…there was a brand called Whisper Fan, now there’s lots of stuff for that. An easy solution that should help even in the smallest dwellings.
Nelson Pass designed a 40 watt push pull version of the S.I.T. using the Sony VFET for the D.I.Y. community, it is pure class A. I used this amplifier in my system for 3 weeks recently. It gets very warm but not hot. I don’t see how the First Watt J2 (lower power, 25 watt @ 8 ohms) could result in a significant heat issue unless the room is unusually small and closed in. Charles
zuio I went through this EXACT dilemma recently, my firstwatt f7 in my small non air conditioned bedroom in hawaii was not useable due to heat but it sounded so good. The amp replacement that made me happy is the Folsom TD7297 diy amp pcb and folsom antipole psu, it's a 15 watt class AB amp. You can have a builder make it for you, such as Radu at simpletubepleasures. It makes no heat and sounds as good as my firstwatt, with even more dynamics
Uncola.....was it the fact that the heat became unbearable in the room or the fact you were worried about overheating the amp itself? I just can’t see how an amp can overheat the room with heat.
OK, I see you are making the distinction between Pass Labs and Nelson Pass's designs which would include First Watt. No problem. The F. W. are definitely a mixed bag of circuit ideas by him. charles
I borrowed a friend's J2 for two weeks and enjoyed it the whole time. The case gets fairly warm, but, that is, in part, a result of the whole unit being fairly small in size. In terms of the total amount of heat being radiated by the amp, I only notices that it was slightly more than that of my low-powered pentode tube amps.
I have also heard that same friend's DIY build of the First Watt SIT amp. That was a really nice sounding amp too, but, I suspect it puts out even more heat than the J2.
I don't know of any solid state amps I like over the sound of the two First Watt amps I heard (although I have not looked extensively at solid state amps). I heard the Devialet and thought it was okay sounding, but, as with the case of solid state amps, it did not hold my interest the way good tube gear does. The brand of conventional solid state amps that I find to be nice sounding and engaging is Ayre.
I have also heard that same friend's DIY build of the First Watt SIT
amp. That was a really nice sounding amp too, but, I suspect it puts
out even more heat than the J2.
The J2, SIT-1, and SIT-2 all have specified power consumptions of 200 watts. (In the case of the monoblock SIT-1 that would be per monoblock). And since they are biased in class A the amount of power they will draw from the wall outlet will be essentially the same at all times, regardless of the dynamics of the music or the listening volume. And aside from a tiny fraction of that power draw which ends up being converted into sound, all of it will be converted into heat and injected into the listening room, mostly by the amplifier but to a small extent also by the speakers,
All of the other First Watt amps have specified power consumptions ranging from 150 to 200 watts, and I’m pretty certain that all are biased in class A. So all of them will inject roughly the same amount of heat into the room (per monoblock in the case of the SIT-1). How hot the chassis gets has no direct relevance to that, and as Larry alluded to in his first paragraph above chassis temperature will vary depending on the physical design of the particular amp.
@kosst_amojan, have you heard the J2 or F6 ? I am using a Tannoy Turnberry which is 93db efficient. Not really very efficient but still happy with 20 watts SET. The question is, will the J2 sound too relaxed compared to F6 ?
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