madbeanpedals::forum

Projects => General Questions => Topic started by: J3113 on April 14, 2017, 04:26:29 PM

Title: Fuzz Face transistors swapped?
Post by: J3113 on April 14, 2017, 04:26:29 PM
Hey all!
First time poster here.
I just build a Fuzz Face but there is something wrong with the sustain.  Sometimes my note dies immediately and sometimes it doesn't.  Now that I think about it I guess I have swapped the transistors (Q1=140 hfe & Q= 95hfe instead of Q1 = 95hfe & Q2 = 140). Dealing with ac128k's here.  Also, there's a relatively loud 'thump' when I push the switch.  Now before I desolder and swap them I would like your opinion on the fact if that could what is causing the sustain/'thump' issues. 
Thanks!
Title: Re: Fuzz Face transistors swapped?
Post by: Govmnt_Lacky on April 14, 2017, 11:29:52 PM
A link to the project and/or schematic would help greatly.

Off the top of my head, I would say your sustain problem is a biasing issue and your "thump" might be due to how the pedal's power scheme is set up. More can be learned with the info I requested.
Title: Re: Fuzz Face transistors swapped?
Post by: J3113 on April 17, 2017, 12:08:36 PM
I used this layout http://tagboardeffects.blogspot.be/2010/09/fuzz-face-pnp-tagboard.html
Title: Re: Fuzz Face transistors swapped?
Post by: Timko on April 17, 2017, 09:17:11 PM
Are your transistors socketed?  I have found on some builds that socketed transistors can move a little bit when engaging a foot switch, causing a thump.  Any socketed component could actually be responsible for that.
Title: Re: Fuzz Face transistors swapped?
Post by: Govmnt_Lacky on April 18, 2017, 02:19:15 PM
Something for consideration.....

I have NEVER built a negative ground PNP fuzz. EVER!!! Some have done it but, most have not been able to without..... switch pop!

I would suggest either building it as a positive ground pedal OR redesigning with a charge pump to alter the power scheme.