using the pre-JFET clipping diodes in the ROG Azabache

Started by mordechai, December 30, 2012, 01:15:25 PM

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mordechai

If I understand this circuit's approach...when placing the clipping diodes before the JFETs in this circuit, the signal gets clipped, then amplified by the JFET, but not to a point where the JFET clips it, correct?

When doing this, is there anything "special" one would therefore have to do to the JFET biasing?  Or can the JFET remain biased as it would otherwise be if no clipping diodes were placed in front of it?

I am thinking of applying this to the old ROG "Odie" project, and just want to get a sense of how the JFET might behave different as a result of this, or if it would just behave/function as normal.


Quackzed

i'm pretty sure the jfet would behave normally, its just there to prevent hitting the jfet too hard and making it hard clip. i suppose if you were to precede it with a booster or some other pedal that hits it with alot of volume it might be a bit different- bias wise, but in that case you'd want the leds regardless, because without 'em hitting it with alot of volume would probably be pretty nasty clipping.
nothing says forever like a solid block of liquid nails!!!

Quackzed

also i just realized that theres 2 opposite facing l.e.d.'s so both the positive going and the negative side going parts of the signal will be affected pretty evenly and therefore will keep the signal in the middle of the rails if you slam it with a really hot signal. so it wouldn't affect the bias...
also normally a passive guitar signal is way too low to be clipped by those leds, so its just a precautionary thing and wouldnt clip a normal guitar signal at all, or very very little for very hot pickups...
nothing says forever like a solid block of liquid nails!!!