I built an ACP+ to use as a preamp (to go with the B1 and DCB1) and it is glorious. I've got a lot of experience with class AB and class D amps, but less with class A.
The ACP+ has definitely made me think about building one of Nelson's amps.
At our house, we start out the day by turning the system on and then making coffee. You have to have your priorities.
The ACP+ definitely sounds best when warmed up, but is still workable right away.
Would a full sized class A amplifier operate the same way (decent sound at first, best when warmed up) or would there be a waiting period before we could play the amp?
We are running Elac Unifi UF5 (first series) speakers, which go down to 4 ohm and all of 85 db efficiency. I am not particularly worried about volume as we are using a NAD C326BEE and it has plenty of power and I have put smaller amps on it yet and been fine. While there are occasional drunken Friday's where we play the Dead at full volume, that is not the case 99% of the time.
I was thinking about either the M2x or F6 because of their ability to run 4 ohm. My tastes run toward a warmer and romantic sound rather than brighter and more analytic.
Would the M2x fit better here than the F6?
Does anyone know the power consumption of these amps at idle?
I live in a part of the world that is genuinely cold (-35F/-37C being the coldest I have experienced while living here), but it is also very warm in summer (up to 100F/38C), so heat production would probably limit use of class A to winter, but it would be good to know roughly what kind of power the amp will consume.
Thank you for any information you can give!
The ACP+ has definitely made me think about building one of Nelson's amps.
At our house, we start out the day by turning the system on and then making coffee. You have to have your priorities.
The ACP+ definitely sounds best when warmed up, but is still workable right away.
Would a full sized class A amplifier operate the same way (decent sound at first, best when warmed up) or would there be a waiting period before we could play the amp?
We are running Elac Unifi UF5 (first series) speakers, which go down to 4 ohm and all of 85 db efficiency. I am not particularly worried about volume as we are using a NAD C326BEE and it has plenty of power and I have put smaller amps on it yet and been fine. While there are occasional drunken Friday's where we play the Dead at full volume, that is not the case 99% of the time.
I was thinking about either the M2x or F6 because of their ability to run 4 ohm. My tastes run toward a warmer and romantic sound rather than brighter and more analytic.
Would the M2x fit better here than the F6?
Does anyone know the power consumption of these amps at idle?
I live in a part of the world that is genuinely cold (-35F/-37C being the coldest I have experienced while living here), but it is also very warm in summer (up to 100F/38C), so heat production would probably limit use of class A to winter, but it would be good to know roughly what kind of power the amp will consume.
Thank you for any information you can give!
Generalizing a bit. The class A amps I'm familiar with (ACA, F3, Aleph 30) tend to 'open up' once fully warm. It's hard to describe but it's like the dynamic range or speed has expanded and the noise floor has dropped. It's like the amp was tight when cold but relaxed once warm? They're certainly listenable cold but I tend to wait until they're warm before I play my favorites of the evening.
They seem to sound better warmed up (about an hour after power up) though they sound fine after power up.
You should not play a signal through the M2 (of M2x) however within the first minute of power up because its biasing circuit ramps things up rather slowly and you would not like the sound. (I tried it once and it sounded more like a chainsaw than an amp. 🙂 )
For both M2(M2x) and F6, standard power draw is about 150W.
I don't think you can go wrong with either though my current preference would be the M2x.
You should not play a signal through the M2 (of M2x) however within the first minute of power up because its biasing circuit ramps things up rather slowly and you would not like the sound. (I tried it once and it sounded more like a chainsaw than an amp. 🙂 )
For both M2(M2x) and F6, standard power draw is about 150W.
I don't think you can go wrong with either though my current preference would be the M2x.
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Thank you all. This is helpful.
My usual practice is to turn on whatever preamp/buffer that I am using and let that go for a minute or so and then turn on the amp. A couple of extra minutes to let the amp come up would be no big deal. The ACP+ is very listenable right away, but it absolutely sweetens up over time. It sounds like this scales up to full-sized amplifiers.
The wattage use is lower than I would have thought. Good to hear.
My usual practice is to turn on whatever preamp/buffer that I am using and let that go for a minute or so and then turn on the amp. A couple of extra minutes to let the amp come up would be no big deal. The ACP+ is very listenable right away, but it absolutely sweetens up over time. It sounds like this scales up to full-sized amplifiers.
The wattage use is lower than I would have thought. Good to hear.
My M2 with oversized power supply draws 160w (2 channels).
I turn It on and play music inmediately. It sounds strange the first minute (autobias?), good the next 10 min, then gets hot and sounds very good.
My ACA and Vfet sounds right after 5 minutes. Maybe because box is smaller and temperature stabilize quicker.
I turn It on and play music inmediately. It sounds strange the first minute (autobias?), good the next 10 min, then gets hot and sounds very good.
My ACA and Vfet sounds right after 5 minutes. Maybe because box is smaller and temperature stabilize quicker.
Vitorio's comment brings another question.
How bad will it be if the house has temperature fluxuations? In winter, we keep the house around 68-70F/20-21C and in summer the temps may be closer to 80F/27C.
How bad will it be if the house has temperature fluxuations? In winter, we keep the house around 68-70F/20-21C and in summer the temps may be closer to 80F/27C.
My home has equal or bigger fluctuations (it has no heating nor air conditioning). Using Papa's words, the M2 is blimey hot in winter and bloody hot in summer.
Amplifier works flawlessly all year. I believe there is no difference in sound quality.
Amplifier works flawlessly all year. I believe there is no difference in sound quality.