AC where it shouldn't be.

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How much AC is on the rails? a few volts or a few millivolts?

Do you have the DC that you expect when the PSU is not connected to the amp? describe your psu - CRC? how much C and R?

What is your expected rail voltage?

What voltage do you get over R23 and R25? If less than ~4V you won't turn on Q2/Q11 and their drains will be close to the positve rail.
 
If you're getting that much AC then something is seriously wrong. Something is drawing a ton of current, you should be seeing millivolts with that filter. check for a solder bridge to ground or across the rails, backwards electrolytic or backwards FET.

The part numbering I was using refers to Grey's schematic. R23/25 are the 390R in the legs of teh LTP.
 
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