Stromberg Carlson Resto

One good thing about the heatwave is, it gives me a great excuse to stay inside and work on tube stuff. Quite some time ago a good customer of mine gave me his old "college days" hi-fi system which had been packed away for years. The heart of the system was a battered, but intact, Stromberg Carlson ASR-433 intergrated amplifier. It actually had mold inside and my guess is that a cat had got to it once or twice. I thought about scrapping it for parts, but the guy keeps asking me if I've done any work on it yet. I think he wants to see it like it was in it's glory days (and maybe remember some of his glory days too), so I've decided to do a full restoration. I started tonight by literally scrubbing it with an SOS pad. After that I blew it dry with compressed air and scrubbed it with PC board wash. Then all the pots got the deoxit treatment, and now it's baking in the oven at 180 degrees for overnight (I hope the Missus doesn't look in there). I plan on a total recap using Russian PIO for coupling, as well as replacing most of the resistors with metal film and carbon film. I may build individual bias networks for the 6BQ5 output tubes as well. I did give it a test run just to check out the iron, and it definately has the detailed S/C signature sound. I will most likely offer it back to the original owner after I'm done to try and bankroll some Karma.

I don't know. I've heard that is a particularly fine 6BQ5 amp. You may want to keep it....especially if you put some nice Russian PIOs in there...

You may be right JC, it sure sounded way better than it should have. The thing that gets me is how small the output TXs are, and they still make great bass and lots of detail. Looking over the schematic, it looks to me like S/C did some things a little differently. I'm not familiar with the 6AV6 but it looks like half of a 12AX7, and they use half a 6U8 for a voltage amp and the other half for the phase splitter. The RIAA is kinda cool too. Maybe I'll just have him over for a listen and a steak dinner. :scratch2:

That's looking great Jay. Gary has one of those (or similar) and claims that it sounds as good or better than his Pilot.

RC

Man did I ever screw the pooch last night. I stuck this amp in the oven at 175 degrees and then took the dogs for a nice long boat ride. When I got back to the house, it was full of smoke (and I mean nasty smoke). The deoxit and other cleaners (along with some TX wax) dripped down on the floor of the gas oven and really made a smoky mess. Of course the Missus got home about ten minutes into my mad clean up attempt. Boy was she pissed. :thumbsdn: On a happier note, I put some decent tubes in this dude and am listening to it now. It has a huge soundstage and great tone. I'm just waiting for stuff from Russia now, then the soldering begins.

I'm sorry Jay, I thought you knew that grilled Stromberg was far superior to that baked stuff...