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Author Topic: FAT Freebass / MAM MB33 Problems + Midi channel settings  (Read 84063 times)


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Re: FAT Freebass / MAM MB33 Problems + Midi channel settings
« Reply #120 on: May 08, 2021, 02:01:22 AM »

Reviving this thread once again.
New user; first post and seeking for help with my MB33 II.
I have a strange issue with main OUT volume dropping as soon as I turn the distortion pot CW.
The volume drops a LOT as soon as I engage the pot and then goes to zero about 1/3 of the distortion pot's travel.
As I understand from the schematic there's some passive current mixing going on before the signal hits the main OUT opamp which seems like it's only a I-V converter from the sumed current  leaving the OTAs.
So far do good but I don't see any good enough reason for the volume to rapidly drop as soon as the pot is turned.
I get just a little bit of distortion before the signal vanishes.
I have a hunch that it's probably a DC bias issue at play which manages to collapse the whole 13700 but I could be wrong of course.
I haven't actually had a proper look on the circuit but thought to post here in case anyone might have any suggestions.
Possibly help others as well..
« Last Edit: May 08, 2021, 02:07:09 AM by belzrebuth »
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