Kepallino_fr

Hello, I am having an issue on my new second hand Ampeg Scrambler. I play it via a passive bass (Squire Vintage Modified '70 Jazz Bass, 4 strings EADG tune). Bad saturation (farting sound) when playing even with gain and blend at zero disregarding the volume setting in the pedal. I tried the following as debugging: replacing power supply, both audio cables (bass->scranbler->amp), I played it on my amp and speaker, I played directly on my audio card and headphones ...I can reproduce the issue no matter what I do. I brought it back to its owner and we tested it with his Fender Precision, no issues at all. I brought it to a tech, his opinion: nothing wrong with the pedal, It must be me not liking it (or vice-versa) .... Any idea where this issue might come?? Thanks for a reply, Sergio