After doing some frequency and phase sweeps on the 33 I built replacement
amp boards usinf TL074 bi-fet op-amps. The effect was noticable. They went
from a response of 50Hz-18KHz at -1dB to 22Hz-243KHz! Mind you, that may be
because I took the tone controls out of circuit in the process! The only
disadvantage was slightly increased hiss.



But is this really a Quad 33 anymore, other than it looks like one?..
--
Tony Sayer