New BFDR Build and First Time Chasing Hum

[JoeTele]

Hi,

I recently powered up my new Weber 6A20/DR build. It's the most complex amp I've built in that it has 2 channels and and reverb (ditched the vibrato). All in all it seems good, but I'm getting a lot of hum in the Reverb channel when I try to switch in a lower bypass cap (.47uf) on the input stage. I like this effect a lot and play my Super Reverb build in that position almost exclusively when I play it loud. I really like the bass cut. I've read that a larger bypass cap will lower hum, so I pulled the bypass cap altogether in the normal channel to make sure that the hum is not in both channels but only exposed with the .47cap in the reverb channel and indeed there is no hum in the normal channel even without the cap. The hum is proportional to the volume knob in the reverb channel, and is present with the reverb turned all the way down/off. It is the lowest, smoothest variety of hum, as if someone was playing a bass with an e-bow and the tone turned all the way down. Any ideas?

Thanks!

Joe

[JoeTele]

Never mind. On a whim, I swapped my pre-amp tubes for channels 1 and 2 and that took care of it.

Joe

[Stevem]

Easy fix!