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DIY Stompboxes => Building your own stompbox => Topic started by: Smoky Barnable on December 20, 2009, 04:16:39 AM

Title: Troubleshooting big muff tone
Post by: Smoky Barnable on December 20, 2009, 04:16:39 AM
I just had a general question about my ggg big muff violet version I recently put together. The tone seems off to my ear. When the tone is turned all the way up it has a cool mosquito fuzz sound that's very trebly but when I turn the tone slightly down it instantly becomes really muffled....like there is no midrange. In other words if my tone level range was 1 to 10 then it sounds very muffled from 1-9 and on 10 it instantly becomes very shrill. My voltages seem normal on my transistors. Any troubleshooting tips?

Thanks.
Title: Re: Troubleshooting big muff tone
Post by: Mark Hammer on December 20, 2009, 10:15:57 AM
Sounds like you have the wrong pot taper.  The tone control should be linear taper so as to provide a smooth transition/pan from the highpass filter output to the lowpass filter output.

Apart from that, you can play with the extent and location of midscoop by consulting the various documents on Jack Orman's AMZ site:  http://www.muzique.com/lab/main.htm
Title: Re: Troubleshooting big muff tone
Post by: Smoky Barnable on December 20, 2009, 10:32:35 AM
I did have the log and linear pots switched around! I assumed all the pots were the same when I got my kit. I didn't realize they were different until I looked closer at the wiring diagram.

Thanks.
:)
Title: Re: Troubleshooting big muff tone
Post by: John Lyons on December 21, 2009, 02:28:32 AM
That being said, the BM tone control has a small
sweet spot and a good amount of mid scoop normally.