SHIN-EI GGG Alternative mod

[daily.demotionals]

Hey everyone. I'm interested in introducing an option to alternate between 2 types of High gain transistors with a dpdt toggle switch.  How would I go about doing that? Here's the original below.  I'm looking at switching the pair (Q1 and Q2) between a pair of MPSA18 and BC184LC.  I'm semi new so please take that into considerations.  Thank u for your time!

[anotherjim]

I think you'd want a DPDT for each transistor although you can get 4PDT.
You can have all the emitters permanently connected to 0v. Have the switch change over the base and collector connections.
In theory, you could have all the collectors connected to their respective places too and do it all with a single DPDT and only swap the bases - but you have to make sure the deselected transistors base is switched off. It should just float off, but a little leakage current could partially turn it on. A 10M resistor between all the transistor bases and 0v should work without altering the circuit character too much when it's selected.

For confidence, I'd go with the first option of a pair of DPDT then you can switch each transistor independently.

[Mark Hammer]

1) Install sockets for the two transistors, and try out a few, taking care to note any pinout differences.

2) Q2 is the one responsible for the fuzz.  Q1 just brings things up to a level that allows Q2 to take over the top.

3) It's hard for me to imagine the need for anything higher-gain.  The stock 2SC536 transistors are not really any different than a 2N3904 or 2SC1815 or 828.  Besides, the "gain" is not inherent to the transistor itself, but is set by the components connected to the various pins.  Whatever sonic differences you might hear are not so much the transistor itself, but whether R3 and the collector resistances to V+ push the specific transistor into clipping.  I'm sure the same tone could be achieved by fiddling with those resistances, using a transistor whose hfe would classify it as "low gain".

4) Part of the "intensity" of the sound of the unit comes from the mids, which are largely scooped away by the filter network after the "Fuzz" control.  Sticking a small resistance between C7 and ground (e.g., 470R-2k) will "lift" those mids and yields a "throatier" and more intense sound. The pedal will also be louder because you're not bleeding off as much.