Originally Posted by
RothwellAudio
Yes, the diagram is too small to see the numbers clearly but the long tail pair seems to be TR21/27/28/29. A simpler and more common circuit would have just two transistors there. The "long tail" is sometimes just a resistor but in this instance has been replaced by a constant current source formed by TR36 and TR37. Again, a single transistor is more common. Sorry, I can't even find TR2, TR3 and TR4. I think a bigger, clearer diagram is needed.
Really, all parts of the total circuit are doing something (or else why have them there?) and although the idea of a simple "signal path" is appealing it's actually quite misleading and explains why people say "resistor X is in the signal path, but resistor Y is not" when it's really not that simple.
AVI started numbering them at the pre section.
Modified SB Receiver, SB Touch, GustardX16 DAC, Mitchell Alecto Mk2 Upgraded, DCB1 hot rod with BTFSystems LDR and input board, Club27 Kurt Mk2 with crossover upgrade and Laquor pack, Tannoy XT6F, IPL S2TLK CD3, Pioneer PL550 (thanks Andrew) Various TDA1541 CDP's, too much shit I dont use to list.