Hi all,
I've noticed the following in 2 of my boxes...
EHX Small Clone (stock), big box - when there is no signal from the guitar (i.e. tuning bypass, turning the volume fully down, or using a killswitch), there is a continuous tone. I've found it's near enough middle C, 261hz. I haven't tested this with a battery in place of an isolated power supply.
K&K Trinity System Preamp - I've modded it to include an external DC input (pedal board style), so it can run on battery as usual or be plugged via a standard pedal adaptor. No problem on the battery, but when plugged into the isolated power supply, the middle C sine wave returns! This time, the problem is only on the mic signal, and it is only audible when the mic is turned on (it is therefore present during performance).
This doesn't occur in any of my other units using the same isolated supply! Modded or stock, self build or professionally built, the problem only occurs in the above cases.
Question, is there a simple circuit I can place somewhere in the pedals to remove this unwanted noise?
It is a particular nuisance in the K&K Preamp. I dislike using batteries as I have no faith in myself to check and change them regularly enough! Much prefer a solid, stable, mains connection.
Thanks in advance,
Edd