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    Building, troubleshooting and testing of these amplifiers should only be
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Help with Preamp/Amp hum

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grufti

grufti

Member
Joined 2004
For more of the same you might try pulling the ps out like you did in your first picture and also putting it on its side so that the transformers face either right or left. That might give you some more clues how you can avoid the coupling that seems to occur.
 
lt_texan

lt_texan

Member
Joined 2005
Power supply rotated 90 degrees CCW and moved to the right. What a difference! Minus 10dB!!!
 

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grufti

grufti

Member
Joined 2004
You're on the right track. Find the best orientation, then work on shielding to find out where you pick up the interference in your amp. Shielding could be your final answer, but the earlier suggestions on where you might be picking up the hum are probably your best bet from this point on.
 
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