Quad II original monoblock pair

GEC tubes, original condition, working properly; cleaned, operated and thoroughly checked by a professional audio technician, these amps have no issues. The Quad II was a current model from 1953-1958 and are rare in this kind of good condition. (There is a great Stereophile article about them by the inimitable Art Dudley, the all star Stereophile scribe. The following technical description is respectfully excerpted from Mr. Dudley's article.)

"The Quad II amplifier, whether sold singly or in pairs, was meant to be used with a Quad preamplifier, which had no power supply of its own, and took its DC plate voltage and AC heater voltage from the power amp. (This is why, anecdotally, Quad II amplifiers with the greatest need for power-supply servicing tend to be those that have been in service with Quad preamplifiers and other Quad ancillaries for the longest times.) Thus, any Quad II in original condition has an input socket not of the usual sort, but rather a thing called a Jones socket, intended to mate with a corresponding Jones plug. This was and is a six-tab connector, apportioned here among two 6.3V AC conductors, one 340V DC conductor, one line-level audio signal conductor, and one ground — that last connected by jumper to the remaining unused tab."

So yes, you cannot just hook these up and run with it. You'll either have to modify them to accept modern RCA jacks (as explained in the aforementioned article), or use the stock Quad 22 preamplifier with them.

Amplifier serial numbers #17924 and #18022

See my other ad to check out the matching Quad 22 preamp.