Hello enthusiasts.

I bought this amplifier over a year ago on Ebay as a fixer-upper, It was apparently out if a Stromberg Carlson Radiogram.
It is all complete except for the rest of the radiogram, It is just an amplifier chassis with the Model IQA79 engraved/ stamped upon it with a serial number. I cannot find any information on it unfortunately. So unsure what year etc etc.
Is anybody familiar with such an amplifier? If so where may I find a schematic so I can work out what's what and get it working. I have speakers and spare turntables and way thinking about making a bitsa project!
Cheers. Jamie.

Valve line-up?

Not really sure, there's a 6V6 or two, I'll have to get it down out of the spare room and have a look, I think one or two might be missing.

6V6 or two

That would be the power output tube or tubes.

Is this a mono or stereo amp?

Depending on the amp's design you should also have pre-amp and possibly phase splitter valve as well.

And presumably a rectifier valve, unless it's in the era of silicon diode rectifiers.

No it's very old, mono, octal valves. 3 Big square metal boxes on top...

JamieLee,

What you have there is a Stromberg Carlson 10A79 chassis.

This has a pair of 6V6GT's for the output, a 6SN7GT phase-splitter & another 6SN7GT + 6SQ7GT (with its diodes plates not used) as pre-amp valves. All up a total of 10 valves including a magic-eye.

Going by the model code it dates from 1949.

A schematic can be found in Volume 8 of the AORSM.

Wow, yes I believe that is what it is, at first I was scratching my head, as mine doesn't have 10 valves, but the unit apparently has 2 chassis's, so what I have is one of the two, the one without the radio tuner, I'll need to see if I can use it just as an amplifier (which is what I bought it for hoping), if not I'll happily donate it to somebody who has use for it...

I just had a closer look at the schematic.

The amplifier chassis consists of only the power supply, the output valves & the phase splitter. The pre-amp valves are on the radio chassis.

Stromberg Carlson 10A79 Circuit Diagram

Oh nooo, with no preamp, it's not going to amplify anything usefully, I wonder how hard it would be to retrofit a functional preamp? The heater circuit shouldn't struggle too much for one or two extra valves one wouldn't suppose? A juicy preamp would be good if to overdrive the output, making a good guitar amp possibly? Hmmn. Getting ahead of myself! I did buy it s a project though... Or should I palm it off yo somebody... Anybody in need of one of these?

Document uploaded to Post 8.

Hmmn a bit of a dogs breakfast, Looks like 4 & 5 are the input signal from the preamp, I'm going to have to think of what might work best as a pre-amp, which I might be able to cannibalise into those input lines... Suggestions are welcome...

Input from the pre-amp chassis is pin 5, ground is pin 6. Pin 4 is the HT supply to the pre-amp and tuner chassis, so don't use this.

There is only one input (pin 5), although a quick look at the chassis could suggest stereo, with 2 output valves and two speakers.

Harold