Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: TerryD on July 10, 2014, 07:59:30 am

Title: Voc AC30c2 power drain-diode & bias
Post by: TerryD on July 10, 2014, 07:59:30 am
Whats the easiest way to drain the power on these new type of crap multiboards?
I'm replacing diodes 7,8,9 & 10/rectifier with 1200v/11A HexFreds. I've done this three or four times before.  Just did it on my Blues Junior. It aways takes a little unwanted rasp out and softens the pick attack just enough.  I don't think I've ever had to rebias an amp after but can't really remember.  Any one know if this swap will get me in trouble on the VoxAC30.
Also, there is another stray diode =D12.  Anyone know what that is?  I'm wondering if I should FRED that as well.
 
Thanks,
Terry
 
Title: Re: Voc AC30c2 power drain-diode & bias
Post by: sluckey on July 10, 2014, 09:54:46 am
Quote
Whats the easiest way to drain the power on these new type of crap multiboards?
Put a ground strap on V1-1.

Quote
Also, there is another stray diode =D12.  Anyone know what that is?  I'm wondering if I should FRED that as well.
D12 supplies +27V for the SS circuits. D13 supplies -27V for the SS circuits. FREDs should do as much magic there as they do in the B+ supply.
Title: Re: Voc AC30c2 power drain-diode & bias
Post by: kagliostro on July 10, 2014, 10:42:29 am
Quote
FREDs should do as much magic there as they do in the B+ supply

 :icon_biggrin:

Ciao Steve

K