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Hoffman Amps Forum image Author Topic: grounding bias filters  (Read 1928 times)

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Offline dude

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grounding bias filters
« 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.
If it ain't broke, don't fix it.

Offline sluckey

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Re: grounding bias filters
« Reply #1 on: March 29, 2018, 02:06:48 pm »
Bias voltage feeds the power tube grids. What do you think?  :think1:
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline dude

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Re: grounding bias filters
« Reply #2 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.
If it ain't broke, don't fix it.

Offline Colas LeGrippa

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Re: grounding bias filters
« Reply #3 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
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