Fun with amplifier distortion!

I meant to also mention that since this is effectively the pre-amp for the replay head, it's dealing with extremely weak and delicate signals. By the time those signals hit T14, they're still too small to be seen on a scope even at the 5mV lowest range and are buried well and truly in the noise. So I've been unable to glean any clues by probing T14 or probing the components around T14 either. I was only able to spot this stage as the culprit thanks to Liz Tuddenham's high impedance probe+ audio amp suggestion (HT, Liz).

If DC voltages check out OK and AC signal is good at T14 base but bad at the collector maybe check the emitter cap C22 and also that only 1 of the 4 equalizer transistors T9-T13 is on? Another possibility is something downstream of C25, not shewn in your diagram, is overloading or distorting? Finally T14 itself could be damaged?

piglet

It’s always surprising how a tiny amount of crossover or clipping distortion can sound much worse than the numbers alone would suggest, especially on vocals and higher frequencies.

I've found that checking the output with a dummy load and an oscilloscope can reveal a lot before connecting actual speakers. It's a much safer way to see whether the distortion is clipping, crossover distortion, or something else entirely.