Seeing the latest SC thread, I was reminded of one of my 'back burner' projects, and if it's worth the trouble . . .

I have two of the old Stromberg Carlson PA amplifiers from 1951 - AU34's. P/P 6L6's . . . . I've seen threads and websites on modifying other models, and wondered if these AU34's have potential as Hi-FI use. I have visions of converting them to 1625 PP amps, and simplifying the circuit - make them more of a line amplifier without the tone controls.

Is this feasible, or should I just recapp them and toss them on ebay for the guitar guys to fund other projects?

thanks for any input : )

The output transformers are the main limiting factor. Not enogh inductance for really good bass, coupling isn't great so HF response is limited as well. When I get home I'll look up some data - I tested one from a Stromberg SR-406, which is similar to a '50's PA amp.

I'd probably use them to drive a fullranger (12, or 15) OB, with a sub filling in the lowend, and a horn tweeter up high, but I'll wait to hear from you. Maybe my nephew will be gettign a cool guitar amp for x-mas :smoke:

I have a pair of stromberg carlson pa monoblocks from the 60's. They were modified for hi-fi use although the stromberg people weren't optomistic about the outcome at all. I love em. I'm not sure of the model number but they each have 4 kt 88's apiece. I believe a 6l6 could be substitued for the kt's though. Bass is solid, highs are nice and they sure are purdy to look at all lit up. One of this winter's projects is for me to totally recap these units. Then I think I'll really have something sweet. I'd get those up and running Markus you just might be very surprised. Good luck

I figure I'd be using them for a (relatively) narrow passband, so if the amps got a built in low and high rolloff, all the better - just might correspond to a good crossover point for the sub and tweeter. Did I mention I'm lazy?

(don't need a complicated crossover ? YEEHAW ) :rockon:

the 1625 is supposed to be a beefy 6L6, so with socket replacement and a rewire of the B+ to the plate cap, I'll be off (theoretically). The 1625 can take more voltage, so I could get some serious power out of them. 'Cause you know, it's nice to have a little 'Just in case'

I've never tried them, but have heard that the 1625 is built like a tank. Good luck, Jay

Never seen this Stromberg & Carlson Amp before up on ebay. No. 21 from the '40's?
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http://cgi.ebay.com/STROMBERG-CARLSON-No-21-MONO-AMPLIFIER-TUBE-AMP_ (http://cgi.ebay.com/STROMBERG-CARLSON-No-21-MONO-AMPLIFIER-TUBE-AMP_W0QQitemZ140051268198QQihZ004QQcategoryZ73369Q QssPageNameZWDVWQQrdZ1QQcmdZViewItem)

That is a nice one - potted transformers, dual channel - easy to convert to stereo. I haven't seen many of these.