madbeanpedals::forum

Projects => General Questions => Topic started by: JC103 on May 31, 2017, 03:23:50 PM

Title: Mosfets as diodes in the Big Muff?
Post by: JC103 on May 31, 2017, 03:23:50 PM
Just curious if any has tried mosfets as diodes in a big muff build? Worth exploring? Also a link to Coda Effects who has retrieved the old "big muff mods and tweaks" page that has passed on into the great archive in the sky.

http://www.coda-effects.com/2015/11/big-muff-mods-and-tweaks.html (http://www.coda-effects.com/2015/11/big-muff-mods-and-tweaks.html)

Title: Re: Mosfets as diodes in the Big Muff?
Post by: thesmokingman on May 31, 2017, 03:37:17 PM
if they're wired as MOSFETs with the small value series diode(bat41/1n34a) you can expect Vf to increase to somewhere between 1.5V-3V depending on the MOSFET. more volume, less compression, different clipping character.
Title: Re: Mosfets as diodes in the Big Muff?
Post by: somnif on May 31, 2017, 08:02:47 PM
I know the Aion Halo pcb has doubled holes on the diodes to allow for FET use, havent played with the idea myself though. You just need to link the drain and source (for jfets) or drain and gate (for mosfets).
Title: Re: Mosfets as diodes in the Big Muff?
Post by: Ralfg on May 31, 2017, 08:59:20 PM
Check out the Skreddy Top Fuel. It's a mosfet input stage with mosfets in the clipping stages. I built one and it's become a goto distortion sound for me. I think it's always worth trying something out, see what you get.
Title: Re: Mosfets as diodes in the Big Muff?
Post by: Max on June 01, 2017, 10:50:22 AM
I was also playing a little bit with the idea of replacing the clipping diodes with JFETs (or MOSFETs, now that you mention them), any idea of the differences in sound between the two?
I need a breadboard to experiment...
Title: Re: Mosfets as diodes in the Big Muff?
Post by: JC103 on June 01, 2017, 01:26:07 PM
FET / MOSFET: if you tie together the drain and gate of FET / MOSFET transistors, they will behave like diodes. Sound is similar to silicon diodes, a bit smoother. (from the coda link)

Smoother? That caught my eye.
Title: Re: Mosfets as diodes in the Big Muff?
Post by: Netnnk on June 01, 2017, 02:44:17 PM
I like the mosfet setting on my Pharaoh Supreme clone.  I'm going to try the Top Fuel soon, as Ralfg mentioned.