#1
Hi, I've had a Harley Benton GA5 (exactly same as a valve junior combo) and decided to mod it recently.

Done the master volume mod, and a few gain increase mods

But now its got a wierd sort of farty, weak fuzz sound about it when I turn up the 'gain' (which is a 1M pot before the second triode) and when I boost it with a DOD 250 it still sounds farty too..slightly better but still bad.


Anyway I can cure this to get nice smooth overdrive?


I have attached the original schematic, an updated schematic with my mods in red and theres a soundclip of a short jam going through settings what it sounds like on my profile.

All are on the bridge humbucker, split occassionally (you'll notice clarity increase) during the silence i adjust the gain and master volume to keep the same overall volume.

The distortion isnt power tube, im sure of that. I have a feeling its because I havnt thought about balancing the gain stages..just going all out:P

I hope someone can help

Modified Schematic:


EDIT: The tubes are stock, If that makes a difference?
Attachments:
HB-GA5.pdf
Last edited by Entrant_21 at Jul 28, 2008,
#2
That's the same thing I experienced when modding mine. The tone sounds weird and fuzzy and without much sustain. Odd. I can't dial out that tone fully.
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#3
I have read a few items on blocking distortion..and I think it may be that.

I've got to work on controlling attentuation between the stages I think to solve it