Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Leevi on February 28, 2015, 03:28:25 pm

Title: What is causing this?
Post by: Leevi on February 28, 2015, 03:28:25 pm

What might be a reason for a long lasting tone (note) when playing with higher volume.
It doesn't sound like rattling tube but more like a distorted note.


I think it could be some kind of oscillation?


For more information see the schematics attached.

/Leevi

Title: Re: What is causing this?
Post by: shooter on February 28, 2015, 09:38:29 pm

with and without vibrato?   I'm not positive but "3" coming off the speaker appears to be negative feedback?, you could try putting another 300k in parallel with the existing one, that should increase the NFB, at least for testing.
Does it "build", get louder the longer you hold the note?