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DIY Stompboxes => Building your own stompbox => Topic started by: mordechai on July 18, 2017, 09:41:45 AM

Title: some "soft", low gain PNP silicon transistors...
Post by: mordechai on July 18, 2017, 09:41:45 AM
I'm building up a Buzzaround circuit, and some of the build reports have commented that subbing in a low gain silicon PNP in the Q2 position cuts down on noise without affecting the authenticity of the tone.  Anybody got suggestions about which devices might work well?  My Q1 transistor is a very low leakage 2N404 (at about 75 Hfe), so I'm guessing that a device sitting aroundf 50-70 Hfe for Q2 would do the trick...
Title: Re: some "soft", low gain PNP silicon transistors...
Post by: wordtobigbird on July 18, 2017, 02:26:40 PM
Russian KT transistors. Theyre little coloured box shapes in either yellow green or red. Cant remember the designation but they come in pretty low hfes. Only issue is theyre ECB pinout but a little vero and some jumpers takes care of it.

Heres some - http://r.ebay.com/lP9F4C
Title: Re: some "soft", low gain PNP silicon transistors...
Post by: antonis on July 19, 2017, 07:12:13 AM
Or place a feedback cap of some tens to hundreds pF between Collector & Base...
Title: Re: some "soft", low gain PNP silicon transistors...
Post by: digi2t on July 19, 2017, 08:28:25 AM
2N2904A

It's what I used in my Skyripper in place of a Ge, and it rocks. They tend to sit in the same gain range too.
Title: Re: some "soft", low gain PNP silicon transistors...
Post by: mac on July 20, 2017, 06:27:45 PM
Try power transistors, BDxxx or TIPxx.
Low gain and high output capacitance like many germs.

mac