Fulltone OCD versions

[johngreene]

>The type of mosfet has nearly zero influence on the sound, only the internal protection diode is used for clipping.

Hmmmm wonder where he got that from?

Actually I have to admit  I sent him a drawing and info on using MOSFETs as diodes before Aron did his pedal. I don't even remember why we were emailing back and forth at the time, it was before I built the GlassPak and was experimenting with using MOSFET diodes on a tubescreamer circuit. He said I should be careful about just 'giving' ideas away like that because I could actually profit it from it if I played it right. I didn't really care much about it then though. If he used this info for the OCD, I have no idea, but he did have 'prior knowledge'.

--john

[aron]

>Actually I have to admit  icon_redface I sent him a drawing and info on using MOSFETs as diodes before Aron did his pedal.

But John, you used you didn't use the _internal_ diodes. That's the big difference between your MOSFET use and mine.

[johngreene]

>Actually I have to admit  icon_redface I sent him a drawing and info on using MOSFETs as diodes before Aron did his pedal.

But John, you used you didn't use the _internal_ diodes. That's the big difference between your MOSFET use and mine.

I didn't use the internal diodes in my pedal, doesn't mean I didn't try it, experiment with it, etc. Also, you didn't -know- you were using the body diode until after a rather lengthy discussion on the forum (was it ampage?).   

There were more people than you that tried this, but in the MOSFET diode connection, it is really sensitive to the MOSFET you use and each and every person assumed they had the extra diode in wrong and flipped it over (so it uses the body diode) and decided that was 'better' because it was a more pronounced, harder distortion. My point being, several people followed the same path as you pretty much independently, they just didn't post any schematics.

Slightly off topic, I just dug through my junk box last weekend and dug out a tubescreamer board I did Jan 1, 1998 that uses the body diode of MOSFETs for clippers. In the feedback loop AND to ground after. I also have one that uses JFETs wired as diodes. I also found several amp simulators I did with JFETS from 95 and 96. I have a Fender version, 2 Marshall 18 watt (EL84) versions, one that even uses an output transformer (it took a lot of work to get the biasing right and still have gain) and one that doesn't. But I have a feeling that if I came out with a pedal that uses any of this decade old development I did, I would be accused of 'stealing' from schematics published here just in the past year. I find this growing trend of "I published it first, therefore I own it" attitude rather disturbing.

--john

[WGTP]

Do we know for sure which way the OCD is using the mosfets?

John has been very helpful lately with explaining the various ways to use mosfets, and I for one greatly appreciate it.