[Dirk]

In the chassi I have 2 screws for the ground, one for the main input and one to the others components:

make sure that you have only ONE star ground and NOT TWO. Otherwise you might have a ground loop which cause problems.

best regards, Dirk

[danieleb]

Thank you very much for your patience
I have only one star ground, the first screw is the ground from the 220, I'll try tomorrow to lift it and see if the noise change

[Dirk]

Thank you very much for your patience
I have only one star ground, the first screw is the ground from the 220, I'll try tomorrow to lift it and see if the noise change

Don't remove the PE or run the amp without a PE connected !!!

Did you remove the cable ties ?

Regards, Dirk

[Dirk]

and can you remove the foot switch ? Just to make sure it is not the switch itself.

Best regards, Dirk

[danieleb]

Ok, I don't remove the ground.
Yes, without the footswitch the noise remains.

The only ground not from the star ground is the cable from pcb to dwell pot but is in the same position of the layout

[Dirk]

I have no further ideas at the moment. It is up to you to find the mistake.
Again: the Reverb works fine and was build many times yet without a problem. All reported problems had their origin in mistake in the build.

Best regards, Dirk

[danieleb]

Ok, thanks Dirk

[Dirk]

Hallo,

your build arrived meanwhile and we have tested and fixed it. The problem was caused by a very bad grounding. You gave used the chassis as ground and there were at least five ground connections to the chassis at five different points plus the PE. We have changed the grounding to star ground and now the reverb works fine. We have also fixed the power supply which you are using because it had a bad solder lug.

I have attached some pictures of the reverb unit. It very compact and the chassis is pretty good. I would use isolated jacks for the in and output too but there is no space left so we must stay with jacks which you have used.

Best regards, Dirk

[danieleb]

Hi Dirk, my version is the tube reverb, in my layout the grounds are one for the 220V and a star on the chassis for the rest of components, the female jacks are connected (the grounds) together and after to the pcb, it could be considered a second star, when a reopen the unit I can try to go directly to the starground on the chassis to reduce groundloops