Pushme Pullyou transistor experiments with 2N3904, 2N5089, OC76 and AC125

Posted 2007-10-17 in Effects by Johann.

I built Tim Escobedo’s Pushme Pullyou which is a simple DIY octaver.

It’s been said that the Pushme Pullyou sounds better/has a more pronounced octave the more mismatched the transistors are (in terms of gain, I think).

Pushme Pullyou sound clip

• Pushme Pullyou transistor experiments (MP3, 1.8 MB)
• Pushme Pullyou transistor experiments (Ogg Vorbis, 1.3 MB)

In this audio sample, I’m trying various transistors. These include the 2N3904 and 2N5089 which are NPN BJTs and OC76 and AC125 with are PNP Germanium BJTs.

1. 2N5089 with OC76. Good octave-up.
2. 2N3904 with OC76. Dirty but no octave-up.
3. 2N3904 with AC125. Dirty but no octave-up.
4. 2N5089 with AC125. Good octave-up, maybe a little better?