Classic Hifi Care

It's now 1922, Western Electric creates the A7 Triode Amplifier and we had "twisted wire" line stage for telephone. Battery operated, 216 triodes, no feedback circuitry, that came later with the Williamson designs. I was given this amp many years ago. ATT likely paid for these early designs, to my knowledge, they were it when phone started. My grandfather had the propensity to purchase many shares for pennies, early on. The family still owns them.

I've heard one of those amplifiers playing through a modern speaker with a CD player as source.

The fidelity was excellent, a real testament to their engineering.

It was 'soft', the same term used to describe the later 41-42-43 series theatre amplifiers, just less power.

Very nice example, BTW.

DG

Since I have a lot to learn about the early audio equipment, that runs on 120 volts B+, 6 volts positive to the tube filaments, 6 volts negative for bias. I'm not clear on the smaller batteries. I see #746 is connected in series with the other one. How does that work? 756 appears to be a 22 1/2 volt battery. I don't believe I've ever seen tubes like that before. Does the volume control work on the signal or on tube element voltages? Thanks for sharing that, Dave.

It is interesting how hard rubber panels distort with age, as opposed to Bakelite.

DG

Not exactly 300Bs,are they? And all transformer-coupled, with few frail components to deteriorate. Cool

Chris Campbell