Hi --
I'm looking to obtain one of the later version selector switches for an SCA-35 I am restoring to original condition for basically a museum/reference piece.
My existing unit has the early type selector switch in it that has a finger installed at terminal #2 on the rear side of both switch wafers. These fingers serve to short the output of the preamps to ground when low level sources are not selected. The problem is -- and as Dynaco also found out -- this causes the preamps to basically become oscillators in the audio band, which can be heard under certain conditions of no signal.
Early versions of the schematic show this finger, which my unit has. Later versions of the schematic have this finger removed, so I'm assuming there was a production change in the switch to remove it, as removing this finger does solve the oscillation problem.
At any rate, if anyone out there has a newer type switch without the finger that they would be willing to let go of, I'd appreciate it! I just thought I'd check before attempting to operate on the one I have.
Dave