WOW! It looks like you can still get that JFET but it cost around $12.00!!!! They are a lot cheaper on ebay but you risk fakes....jarrodthebobo wrote: ↑05 Dec 2020, 12:43I had used a combo of 2meg trimpots and 5.6m resistors in series with them in replacement of the two biasing resistors that go to the transistors in order to have a finer level of control over the bias selection. I also tacked on some 2meg resistors in parallel to try and see if dropping the overall values of the bias resistors made a change for the better for alternative jfets but it didn't for the most part.Carvindc125 wrote: ↑05 Dec 2020, 05:34Nice! Thanks for the heads up.jarrodthebobo wrote: ↑04 Dec 2020, 23:48 Just a heads up;
100% do not try and sub the 2n4339 in this circuit for other fets; I finally caved and purchased a couple and the difference in performance is rather dramatic (and much easier to bias now). I had 100% confidence that a j201 would be a suitable replacment for the 2n4339 since their data specs are quite close in terms of cutoff voltage and such but, save yourself the frustrations of trying to throw something. Upon plopping this tranny in, even without rebiasing it initially, the compression circuit works a hell of a lot better, the distortion 'feels' better under the fingers, less pumping artifacts, more natural decay, and for some reason, more highend (no idea why but a blanket has been lifted so to speak), although I'm not sure if the high end being reintroduced has something to do with the clipping circuit perhaps seeing a more appropriate signal, or the jfet itself having some sort of odd effect.
Did you use a 10M trim/pot to bias?
The other bias method should be sufficient, but two trimpots just gives you the ability to drop pretty much anything in the circuit and get it 'working' at least
I agree with you something about the arrangement with that particular JFET brings in the "Sparkle" using any other JFET sounds dull.
Interesting. But dang between that and the mn007 chip your going to be $24.00 out just on two chips!
Ive heard chorus pedals that sound very close to the "Normal" setting on a Rockman so perhaps some breadboarding is in order. If the effect can be mimic with just a stereo chorus circuit then we will drastically cut part count down and save some money too.
FYI someone has made a Rockman Distortion Generator in a pedal and it sounds really nice! It lacks the compressor and incredible clean 1&2 sound though.