by Guest Sun Feb 07, 2016 11:47 am
as far as tone controls are concerned on the SCA-35, Dynaco came up with a pretty cheap solution. They used a PEC (packaged electronic circuits) for each channel, which had all the components for the tone controls enclosed within. Kinda looks like a giant ceramic capacitor with a bunch of leads coming out of it. I guess one can also call them integrated circuits, in this case, all analog!
These PEC's were directly connected to the tone control pots. They even used PEC's at the phono preamp input for Hi-LO-Ceramic phono cartridges, as the SCA-35 had individual phono in RCA sockets for each of the three types of phono cartridges.
No doubt it worked, using these PEC's, but it was a cheap way of achieving tone controls etc..
I would think, having spent some time looking at the SCA-35 circuit and build, any upgrades and or mods, one would be better off to remove the tone controls and end up with a 'classic' line preamp stage.
For its time, the phono and preamp/amp circuits were quite OK, and there are some very good modern upgrades available, that will breath new life into an old SCA-35, giving you a nice integrated tube amp, pretty much the size of a PAS3.
So I would think it is definitely worth while picking up an old SCA-35, and as long as the transformers are all still good, which are of course the most expensive parts of the amp, it would be a nice amp to upgrade!
In case you're curious as to what a PEC looks like, these are the PEC's used in the SCA-35