Build Your Own Clone Message Board

They do work in the LED clipping section, I shorted the base lead to the emmitter lead, oriented the collector lead in the positive LED eyelet. Doesn't sound bad.

can the mosfets handle 18v if placed in the clipping section????

Great info - thank you!
CEW

Hi,
My OD2 is built according to the original setup, no mods made.
I´d like to change the LED clippers to Mosfet bs170. Will it be enough just to take out the two LED:s and put in two bs170 mosfet transistors in the designated spots next to them (backwards), or do I have to make other adjustments as well?

Yup, that's all you need to do. No other changes needed.

Because of this tonal similarity between the LEDs and the diode "lift", I prefer to build my OD2's with BS170 MOSFETs in the second clipping position.

I take it that installing MOSFETs in the second clipping position is different than the mod with MOSFETs in the boost channel?

And if it is how can i achieve the MOSFETs in the second clipping position? Do other parts of the circuit need to be built MOSFET or can it be done just by switching out the clipping position with MOSFETs instead of LEDs?

Yes, completely different. For the clipping mod, you're just utilizing the internal "body diode" of the MOSFET's to function as a signal clipper. The additional MOSFET modifications are totally different in what they do.

This is covered quite clearly in the posting in this thread immediately preceding yours.

In your opinion which would be the better way to build the OD2, with the boost channel converted to MOSFET or with only switching the LEDS for the MOSFET transistors, like you discussed earlier?

Thank you

I just received the OD2 kit as well and am wondering the same thing.

Thanks!

This is a very subjective judgment, guys, so the following should be taken only as my personal preference:

I like to build the OD2 kit with the following configuration:

1. MOSFET clipper pair instead of the LEDs, since the latter don't sound much different than the middle "diode lift" position of the clipping toggle switch, due to their high voltage threshold.
2. JRC4558D op amp for a bit warmer, grittier sound, or the Burr-Brown OPA2134PA if you want a bit more clarity. (Doesn't make a lot of difference.)
3. MOSFET input buffer for somewhat better retention of the highs in the incoming signal.
4. Stock BJT output buffer for its stronger drive characteristics (a Jack Orman recommendation that I endorse).
5. Stock LPB-style boost stage for more available output and better low-end.
6. Switchable effect order modification.

As they say, "YMMV"!!