Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: kagliostro on August 25, 2026, 05:45:10 pm

Title: Question about grounding
Post by: kagliostro on August 25, 2026, 05:45:10 pm

I'm thinking to a stereo guitar amp that uses two separated circuits and only one PS

I searched about how to arrange the ground sistem and what I think may be useful is to have the input jack insulated from ground and to connect the ground of the two circuits to the chassis via a pair of ground lift circuits

But if I do that I don't know how to arrange the connection of the PS negative

Will it be useful to use a pair of ground lifter also to connect the negative of the PS to the negative of each circuit ? (Before of the ground lifter that connects each circuit to the chassis)

Does someone is expert in Stereo amp (HiFi I suppose) and can help me ?

THANKS

Franco

Title: Re: Question about grounding
Post by: kagliostro on August 28, 2026, 10:49:55 am

I've been thinking about the grounding scheme, and this is what I ended up with:

(https://i.imgur.com/2SYxnU2.jpeg)

The PS ground and the circuit ground are connected to the chassis through a ground lift.

PS will be something like this

(https://i.imgur.com/E0rPiRx.jpeg)

I was inspired by this:


(https://i.imgur.com/e7aKbnp.jpeg)

Do you think it will be useful ?

THANKS

Franco

Title: Re: Question about grounding
Post by: shooter on August 28, 2026, 12:52:09 pm

looks good from here, i built a SS stereo using this as a guide, didn't bother with the start-step circuit, mainly the filtering to the "right" of the PT
can't find the files, IIRC the circuit was silent as far as noise/hum goes

Title: Re: Question about grounding
Post by: passaloutre on August 28, 2026, 05:45:39 pm

I think you’re overthinking it.

All the tube stereos I’ve worked on have a shared ground between the channels.

The stereo Vibrolux I made last year has just one ground. No lift necessary.

Title: Re: Question about grounding
Post by: kagliostro on August 28, 2026, 08:26:23 pm

I've no practice on stereo and so I was looking to what HiFi guys do

That thing seemed feasible to me also because I remember well that in the VOX AC30CC2 there is a Ground Lift like that Merlin suggests and the some in other recent AC15 models

Franco