Realistic Amp

[almalo]

I picked this realistic STA-350 out today at the Thrift. It seems so neat, simple, inside and out! The only reference for it was in the Radio Shack catalog from 1971 : http://www.radioshackcatalogs.com/catalogs/1971_small/ (Page 25)
I am confused about its power rating. Does anyone have ant experience with this model?

 

[mhardy6647]

For those (slightly) less patient than I, the amp in question is on page 25 of the R/S catalog link

Power rating is easy - it is pre 1974 FTC specification. The "55 watts" is a "stereo" rating and probably into 4 ohms. Divide by 4 for something closer to what you're used to seeing (13.75 wpc into 8 ohms)... but that too is probably 30 to 50% optimistic compared to a full-spectrum "RMS" (i.e., continuous) rating per the FTC regulations. The amp in question is probably something like 10 wpc into 8 ohms from 50 to 15,000 Hz at 5 to 10 % THD.

Never saw one; I note interstage transformers - it looks old, and very Japanese, inside.

Cute.

 

[BinaryMike]

I owned several RS components of that vintage when they were new, including an SA-700. The driver transformer allows identical upper and lower side power transistors to be used in the output stage, without certain compromises present in a quasi-complementary design. The basic design is capable of very good performance, but my recollection is that sonics seemed a bit confined -- lacking that elusive quality of spaciousness. Hope that helps.