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DIY Stompboxes => Building your own stompbox => Topic started by: hkpierre on May 30, 2004, 11:13:37 PM

Title: Anyone use Japanese jfet (e.g.2Sk30A) for phase 45 or 90?
Post by: hkpierre on May 30, 2004, 11:13:37 PM
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?
Title: Anyone use Japanese jfet (e.g.2Sk30A) for phase 45 or 90?
Post by: R.G. on May 30, 2004, 11:16:58 PM
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.
Title: Anyone use Japanese jfet (e.g.2Sk30A) for phase 45 or 90?
Post by: hkpierre on May 30, 2004, 11:32:26 PM
THX for the reply!

However, i saw 2Sk30As are used in Funny Cat, are they used for the same purpose as in the phase?
Title: Anyone use Japanese jfet (e.g.2Sk30A) for phase 45 or 90?
Post by: RedHouse on May 31, 2004, 10:43:09 AM
Not to hijack the thread, but I would like to know if 2N5457 would work alright in a Phase-90 circuit?
Title: Anyone use Japanese jfet (e.g.2Sk30A) for phase 45 or 90?
Post by: Jim Jones on May 31, 2004, 02:18:08 PM
I've used 2N5458's with good results...

Jim
Title: Anyone use Japanese jfet (e.g.2Sk30A) for phase 45 or 90?
Post by: R.G. on May 31, 2004, 10:59:57 PM
QuoteNot 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.
Title: Anyone use Japanese jfet (e.g.2Sk30A) for phase 45 or 90?
Post by: RedHouse on June 01, 2004, 09:18:22 PM
Thanks RG, I better go find that JFET matcher on your website.
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