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 Forum index » DIY Hardware and Software » Rob Hordijk DIY Designs
I would like to increase the output level of Zeitgeist
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oscilloclast



Joined: Sep 29, 2005
Posts: 49
Location: VA

PostPosted: Tue Mar 23, 2010 1:14 pm    Post subject: I would like to increase the output level of Zeitgeist Reply with quote  Mark this post and the followings unread

Rob

I have been enjoying my Zeitgeist for quite some time (I switched out the opamp chip and it works great) but there is yet another modification I would like to make. Does anyone know if it is possible to increase the volume of the Zeitgeist output? I know I can run the output through an opamp but I was wondering if I could readjust the opamps in the Zeitgeist instead? The issue I am having is that I really like the sound of the delay at the extreme delay lengths where the signal starts breaking up, but at these setting the volume is rather low.

Thanks,
David
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electri-fire



Joined: Jul 26, 2006
Posts: 535
Location: breda nl
Audio files: 4
G2 patch files: 4

PostPosted: Fri Apr 30, 2010 8:13 am    Post subject: Reply with quote  Mark this post and the followings unread

The output volume is set by U2D. As pin 13 and 14 are shorted it works as a buffer. If you cut the trace and insert a resistor according to taste you get more gain.

This would also affect the amount of feedback you get. If this poses a problem you could replace the jumper before U2B with a resistor or replace R21 with a higher value.

There's a lot going on at that U2D section though, with the filtering capacitors and some (to me) enigmatic voltage bias scheme at the positive input. That might get influenced maybe, I don't know.

You could get brave and just cut between pin 13-14 and see what you get with a pot beween them. It would be easy to resolder if need be, and certainly less work than adding another opamp.


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oscilloclast



Joined: Sep 29, 2005
Posts: 49
Location: VA

PostPosted: Fri Apr 30, 2010 11:51 am    Post subject: Reply with quote  Mark this post and the followings unread

Thanks, I'll try that and see what happens (I'll try to keep the smoke to a minimum).

David
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