Model 33 Transistor Sub

[ocdecio]

Has anyone replaced SPS2296 on a Model 33?



I am thinking on BC550C given the high hFE and low noise, just like I did for 1120's SPS1928 but I wonder if there is a better alternative.

I have a left channel that has a random craclking noise even after recapping.

 

[catrafter]

I have never worked on a 33, but your schematic snippet appears to show a 'differential amplifier'. I would match Q101 and Q102.

Tom

 

[ocdecio]

The manual asks for hFE greater than 400 for these differentials so 2N5961 may be an option (the ones I have hover around 420) but I was thinking the BC550C would be better (they are above 500).
However the same SPS2296 are used later in the circuit as differentials again but now they are being asked to be between 200 and 399 (Q113.Q114).