Amps Atma-Sphere M-60 Mono blocks OTL design

Hi Ozzy,

I wouldn’t infer too much from that 600 watt number. The amp only operates in class A up to "40 watts peak," and beyond that output power level its AC draw will presumably vary with the dynamics of the music. Also, given the amp’s power ratings of 350 watts/channel into 8 ohms (700 watts total output) and 700 watts/channel into 4 ohms (1400 watts total output), obviously it would be drawing considerably more than 600 watts from the wall outlet when supplying anything approaching its rated output to the speakers.  (It can’t put out more power than it takes in, or anything even close to what it takes in given that it is not class D).

Given your earlier mention that your use of the amp has been such that it has rarely if ever left class A, FWIW my rough guess is that the amp has probably been introducing something like 300 to 400 watts into the room.

Best regards,
-- Al

BTW, Ozzie, I suspect that the X350.5 spec of "40 watts peak" for the point at which it leaves class A operation is equivalent to only 20 watts based on the usual conventions for defining amplifier power (corresponding to volts x amps with each defined on an "RMS" (root-mean-square) basis, rather than a peak basis).

So you’ve probably been using very little of that amp’s power capability.

Regards,
-- Al

I am pretty sure you will love those amps.  One of the only equipment sales I regret is a pair of  the M-60s.  Luckily, I now have more efficient speakers and I got a good deal on used S-30 w the V-cap and power boost mods.  Love it.  An added bonus is having the best customer support in the business available to you.