Dual Transistor Configurations

[tjmicsak]

I can find info on Darlington Pairs but where can I find out about the use if back to back transistors, such as the keeley fuzz head and I believe the mossrite or Shin Ei fuzzes that have them paired as a "mirror" of each other? WHat is this arrangement called?

[frequencycentral]

Current mirror loaded differential amplifier?

[aziltz]

keeley fuzz head is from "Long Tailed Pair", kinda like the front end of a differential multi-transistor amplifier, or discrete op-amp.