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Help me spec n class A AMP, power calculation 85dB @ 1W @ 1metre

I was playing few pieces and recoding dB levels on my phone. After playing few tracks I see some parts of music sustains at 88db and peaks at 96db. I do like to hear music at this level for short periods of time. 

I am using the following calculator: https://geoffthegreygeek.com/calculator-amp-speaker-spl/

Sitting at 10 feet away from speakers I see the following numbers:

Assumption amplifier headroom of 1.5 dB, 10 feet distance

For 88db 1 Watt + 14.2 dB requires an amplifier power of 26 Watts
For 96db 1 Watt + 22.2 dB requires an amplifier power of 165 Watts

For 102db (room SPL losses) 1 Watt + 28.2 dB requires an amplifier power of 658 Watts (Ridiculous?)

It would be great if I can go get a class A mono blocks that can do sustained 200 Watts for each speaker @ 8ohm/6ohm and call it day but I got no dough for that.

How do I spec for a good amp(and may be integrated). I would like something that can sustain 35-50 Watts for class A and have reserves for peak of 200 Watts.

geek101
glennewdick's avatar
glennewdick
1,629 posts
 

I don't think you will find such an animal anymore. I think there was one or two made years ago similar to that but not resent (didn't Luxman and Krell make a big power class A). Pass Labs, Sungden, Accuphase and luxman are the manufacturers that come to mind that still make class A but nothing with that reserve power range. Really 50wch class A is about the max your going to find unless the amp also goes into class AB. Pure class A above that requires so much power dissipated as heat its not really practical nor comfortable unless you live in an igloo (ha that actually might be dangerous as the amp would melt the igloo most likely).

Hopefully someone else has a hidden class A gem they know of.

But in your nominal power output of 30-50wch pure class A your looking at Sungden. Luxman. Accuphase and Pass labs. few more but those are the biggest i'm thinking.

One more thing you may be surprised you may not need that reserve power if your speakers are a fairly easy load on the amp.

 Love Class A SS but man they are space heaters. Tube amps are less hot go figure.....

geek101 OP
284 posts
 
The speakers I am considering are 85dB @  8 ohm or 86 dB @ 6 ohm :(.
auxinput
2,920 posts
 
Krell made a series of amps called FPB - Full Power Balanced.  They were all Class A amps, but not in a standard way.  They had an auto-bias circuit and did not push full Class A all the time.  You can tell this because the amps had an idle current that was much less than full power output.  Their new "Chorus/Duo/Solo" series of amps are very similar to this.
geek101 OP
284 posts
 
I am thinking Parasound JC1 , 25 watts of class A ?. Wondering if this will work.
auxinput
2,920 posts
 
Ah.,  JC1 are excellent amps and they will allow you to switch between low bias (10 watts) and high bias (25 watts) Class A.  Generally, Class A will give you warmer and more rounded tones.
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