Jfet design questions

Stompboxes circuits published in magazines, books or on DIY electronics websites.
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jubal81
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Post by jubal81 »

soulsonic wrote:
stole59 wrote:Wow man, I never saw anything like this in Jfet pedal design.
My Shizzle Deluxe Fuzz/Overdrive uses this technique for the JFET input stage. In this case, the bias isn't adjustable, because it consistently gives the right biasing with these values with this transistor...
You will also see this in some of the Russian-designed JFET circuits.
ShzlDlxJFET.GIF
I've been working with similar SMD JFETs lately and I really like this setup.

Trying to deconstruct:
Looks like you set the ID at 60% of the specified IDSS minimum for the Y variant.
Source resistor is about 25% of total D-S resistance.

Then, you select the gate voltage divider resistor value based on a target drain voltage?

I've had good results this way, but my sample size is still pretty small, using JFETs from the same reel.

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