Aleph-X with common-mode oscillation

[DACMan1]

Ones I have is 15.5degC/W which means a temp rise of 52degC but its the best that will fit. However, forward voltage drop on these will only be less than 1V(worst case 1.15V and will drop at higher temperatures. Thus:

2.25*1=2.25W
2.25W*15.5degC/W=35degC

Worst case:

2.25*1.15*15.5 = 40degC

This is acceptable to me.

PS, they will be mounted directly on the heatsink, so lets say a 0.8degC/W case to heatsink junction temp. They have 1.6degC/W junction to case drop.

So the die will run at: (above ambient in case)

(1.6+0.8+15.5)*2.25=40.25degC
*1.15(worstcase) = 46.3degC

at worst case internal temp = main heatsink temp

gives realitic to worst case ratings of die temp 90-110degC.

These diodes will live quite happily at a die temp of 100degC.

Hopefully internal temp will be a bit lower

[DACMan1]

I cant seem to find this in the main thread, the absolute dc offset of my amp starts at around 10V when cold and then goes down to -1V after about an hour. Is this normal?