[sdiy] Humming noise in JH reverb circuit

ganesha goaqihai at yahoo.co.uk
Wed Oct 3 14:47:33 CEST 2012


Hello Everybody.


I unscrewed the reverbtank and held it further away from the transformer and it was much better so the transformer is definitly the cause.
Thanks to everyone for the help!


Best regards,
Kris

----- Original Message -----
From: ganesha <goaqihai at yahoo.co.uk>
To: Paul Perry <pfperry at melbpc.org.au>; synthdiy diy <synth-diy at dropmix.xs4all.nl>; Ullrich Peter <Peter.Ullrich at kapsch.net>
Cc: 
Sent: Wednesday, 3 October 2012, 9:26
Subject: Re: [sdiy] Humming noise in JH reverb circuit

Hi,
Thanks for the answers.

I tried grounding the reverbtank but the hum is still there. But if I disconnect the reverbtank from the pcb, the hum is also there so I have the feeling that the problem is somewhere in the pcb and not in the reverbtank.

The reverbtank and the pcb are approx 30cm from the transformer, but if the transformer would be the cause, wouldn't  the hum be always present? Now it only hums when the mix pot is set to wet signal, and it doesn't matter if the reverbtank is connected to the pcb or not.

Best regards,
Kris



----- Original Message -----
From: Paul Perry <pfperry at melbpc.org.au>
To: synthdiy diy <synth-diy at dropmix.xs4all.nl>
Cc: 
Sent: Wednesday, 3 October 2012, 9:07
Subject: Re: [sdiy] Humming noise in JH reverb circuit

If there is a transformer nearby (within 50cm or so) you could be picking up a magnetic field, and it takes a thick layer of iron to sheild that (more practical is to change the orientation of the tank, if possible.)

paul perry Melboune Australia

----- Original Message ----- From: "Ullrich Peter" Subject: Re: [sdiy] Humming noise in JH reverb circuit


> You should also ground the metal housing of the reverb tank...


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