JFET Question, Umble Circuit

[sjturbo]

I'm going to build an Umble pedal and have been reading up on JFETS. I'm wondering if the omission of the capacitor between gate and source that is supposed to emulate Miller capacitance found in tubes has any effect on this particular circuit. I looked at another circuit, Dr. Boogey and these capacitors are included. I've read that the Umble circuit is somewhat stripped down and wonder if this is the reason for the omission? Appreciate inputs!
Thanks!

[brett]

Hi
emulating the effects of Miller capacitance is handy with JFETs because they might otherwise have humps in their frequency response way up in the RF region.

In the Umble, it probably doesn't matter much, except for JFET2, the one after the tone stack, that is fed by the parallel cap and resistor.  At very high frequencies the cap offers low resistance to the signal.  A very small "HF bleeder" cap might be useful between the cap and the JFET's gate.  10 to 100pF is the useful range.  100pF might just roll off some high frequencies (on the other hand, it's mostly dogs and children that can hear above 12 kHz).
cheers

[sjturbo]

Thanks very much for the input! I built the circuit without the cap but I may try adding it. I guess not many people know about miller cap.

[Caferacernoc]

Another way to do it is too put that small value cap in parallell with the jfet trimmers. That's an easy place to add on to an already built circuit.