Archive of the former Yahoo!Groups mailing list: Discussion about the Korg PolySix synthesizer

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Subject: Re: [PolySix] MG / LFO Q1 transistor replacement.

From: Bob Grieb <bobgrieb@yahoo.com>
Date: 2014-03-10

According to the data sheets, the 2SK30A is  JFET.   The 2N7000 is a MOSFET.    I would suggest replacing a JFET with another JFET, not changing transistor types.

Bob


From: "backshall1@bellsouth.net" <backshall1@bellsouth.net>
To: PolySix@yahoogroups.com
Sent: Sunday, March 9, 2014 10:44 PM
Subject: Re: [PolySix] MG / LFO Q1 transistor replacement.

 
The 2SK and 2N parts have different pin-outs. The clone board is designed for a 2N transistors. To put one on an old original KLM-367 you would have to do the “crossed legs” thing. Actually, I think the Gate is still in the middle, so you would just put it in backwards, no bent legs, just reversed Source and Drain. I’ve been using 2N3819 without problems on the clone boards, and it still seems to be available at Mouser in the US. You could always be the first to try 2N7000 and let us know. I don’t know enough about FET characteristics to say what the 7000 would do in this circuit. DIYstompboxes.com has some discussion about what other people have tried  as a replacement for 2SK30A in some guitar pedals.
Don Backshall
 
Sent: Sunday, March 9, 2014 11:51 AM
Subject: [PolySix] MG / LFO Q1 transistor replacement.
 
 
What would be a good replacement for Q1 in the MG circuit?
 
The original seems to be 2SK30A.
 
Jed's updated parts list for the clone suggests a 2N7000 (not tested I think).
 
From some web research, a substitute may be the MPF102.
 
Would these last two work?