ricothetroll
Well-known member
Hi !
I just built that preamp :
http://www.runoffgroove.com/englishchannel.html
It's a fet adaptation of the classic Vox AC30 Top Boost preamp, to be used as a distortion pedal.
My problem is that I have oscillations on the output. Its frequency is something between 2k and 5k, and changes while turning almost any pot, especially the input volume. The shape is some kind of sawteeth. When the input volume pot is between 10 o'clock and 1 o'clock, there's that strange sound :
http://www.wuala.com/ricothetroll/public/Eng_Chan_Oscillations.wav
(that sample has been recorded while turning the input pot from anti clockwise to fully clockwise)
Has anyone a clue of what could cause such noises ? About how to eradicate it ?
Thanx in advance !
Have a nice day.
I just built that preamp :
http://www.runoffgroove.com/englishchannel.html
It's a fet adaptation of the classic Vox AC30 Top Boost preamp, to be used as a distortion pedal.
My problem is that I have oscillations on the output. Its frequency is something between 2k and 5k, and changes while turning almost any pot, especially the input volume. The shape is some kind of sawteeth. When the input volume pot is between 10 o'clock and 1 o'clock, there's that strange sound :
http://www.wuala.com/ricothetroll/public/Eng_Chan_Oscillations.wav
(that sample has been recorded while turning the input pot from anti clockwise to fully clockwise)
Has anyone a clue of what could cause such noises ? About how to eradicate it ?
Thanx in advance !
Have a nice day.