Anyone use Japanese jfet (e.g.2Sk30A) for phase 45 or 90?

[hkpierre]

Bcoz i can't find 2N5952's in HONG KONG, i tried 2Sk30A for my phase 45. But i got no phase sound..... I use the Jfet matcher and the Vgs is about 0.9V. Is that too low or i have to do something on the zener?

[R.G.]

You might be able to get 2N5485, they work well.

2SK30A will probably work if matched well. 0.9Vgs in a matcher is not unreasonable for them. You might have to mess with lowering the amount of LFO voltage going to the gates. You will probably have trouble with distortion as the signal is comparable to the VGS range, but that's another problem for later.

ANY n-channel JFET with Vsgoff of less than about 3.5V max has a chance of working. The best ones will be about 3.0Vgsoff. Smaller Vgsoff JFETs are much less linear as voltage controlled resistors.

[hkpierre]

THX for the reply!

However, i saw 2Sk30As are used in Funny Cat, are they used for the same purpose as in the phase?

[RedHouse]

Not to hijack the thread, but I would like to know if 2N5457 would work alright in a Phase-90 circuit?

[Jim Jones]

I've used 2N5458's with good results...

Jim

[R.G.]

Not to hijack the thread, but I would like to know if 2N5457 would work alright in a Phase-90 circuit?

Yes - given that you select them for Vgsoff less than 3V; another way is to select them for an Rds of 10K (standard value in my JFET matcher) of two to two and a half volts.

[RedHouse]

Thanks RG, I better go find that JFET matcher on your website.