"Massacre" Online :)

[Joe Davisson]

I revamped the older MOSFET circuit to use PMOS transistors. It's pretty cool!
http://www.i1.net/~joe1/circuits/massacre.gif

Use of the PMOS transistors lowers the background noise level inherent in NMOS devices. It's probably the simplest high-gain overdrive out there...tack on a tone control if you like.

The gain control is sort of a kludge, because it only goes down so far. But it isn't a good low-gain pedal anyway, so I thought of the gain control as more of an input attenuator in case you have high-output pickups.

-Joe

[Chris R]

an appropriate name for Halloween.. ;p

C

[aron]

WOW, hi-gain. YEAH!  

[Doug H]

Looks good, Joe!

A thought just occured to me... I haven't had my coffee quota this morning so it may be stupid, but here goes anyway...

Since the output is inverted, would it make sense to run a NFB loop from the output back to the first stage, using a pot or variable resistor to control gain? You could either inject it at the source or reference the 1st stg source and gate grounds to the NFB loop (which would be referenced to ground through either a fixed divider or the gain pot). Or alternatively maybe use some local NFB in the first stage?

I'm just wondering if using NFB might be a more effective way of implementing a gain control in some of these high gain circuits?

Doug

[Marcos - Munky]

Hey Joe, if you keep making these great effects, we will finish to have a lot of distortions in our pedalboard . Keep the very great work  :twisted: .

[MarkB]

Very cool, Joe!!
So how does it sound relative to an Obsidian, Trans Obsidian, Blackfire, etc?  

"-)

[Ansil]

hey joe i just looked at your sight where you have the coppering section.. pretty neat, but did you know you can get a similar thing to happen by dropping a pedal in etchant solution.  or by simply dropping it on top and letting it sit there or put a sponge in it and set it on top of the pedal, or a paper towel,  brawny is best.  of course it will get hot, and smoke some..  lol

[Kilby]

And then the gif ran away ?

[Joe Davisson]

http://www.i1.net/~joe1/circuits/Obsidian-M.gif

Basically the same thing.

-Joe