Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: dude on March 29, 2018, 01:42:33 pm

Title: grounding bias filters
Post by: dude on March 29, 2018, 01:42:33 pm

Does it make any difference if the biasing filter caps are grounded on a buss bar that runs down to the preamp star ground, picking up the pots grounds, etc, as it goes to the input jack ground?


Or better to use the star ground for the PT and power filters caps, PT bolt.

Title: Re: grounding bias filters
Post by: sluckey on March 29, 2018, 02:06:48 pm

Bias voltage feeds the power tube grids. What do you think?  :think1:

Title: Re: grounding bias filters
Post by: dude on March 29, 2018, 04:21:49 pm

Ok, another stupid question from me :w2: . I’m getting way too anal in my older years.

Title: Re: grounding bias filters
Post by: Colas LeGrippa on March 29, 2018, 04:39:21 pm

Dude, it is better to ground the power tubes with the B+ supply and the preamp tubes all together at one only place: the input jack gnd. What I do is soldering a bare copper lead taken from a 14-2 110V electrical house wiring to the jack input and all the gnds from the preamp tubes go there . Important NOT TO GROUND this lead at two different places to avoid loops. (hum).


Colas