[Musica Amantem]

Originally Posted by Analog Addict

If you don't get back to RTP by Sept, I will be in Asheville for a conference 9/8-9 10, and would be happy to bring my PSE 45 along for a demo. I'm hoping my PSE 71-A will also be ready by then....

I was curious about your interest in the 71-A output tube for your PSE project, so I did some research:

The type 71A vacuum tube was a power amplifier triode intended for use in the final audio stage of battery- or alternating current-operated receivers. It began life, under the old style of tube designation, as the UX-171 and was announced by the Radio Corporation of America (RCA) in May 1926. Operated at its published conditions, it was able to supply nearly 800 milliwatts of audio power, a reasonable amount for a single tube. It was superseded in November 1926 by the improved UX-171A, which featured a lower filament current.

"The UX-171 and 171A were first issued with the “globe” style bulb, similar in appearance to an old-style light bulb. In the early 1930s, the bulb was changed to the “ST” shape (also known as the “coke-bottle” shape), and given the new designation of 71A.

Radio engineers used it extensively in broadcast band radio receiver designs. The 71A provided more audio power than the UX-112A, and the tube was less expensive than the UX-210 or UX-250 tubes. The 71A's only real competition, for design purposes, was the UX-245 power triode.

Today, the 71A has a small following amongst high-end amplifier builders and hobbyists. It was a high-production tube and is relatively easy to find from various tube suppliers (and on eBay)".

What differences do you expect relative to the gorgeous PSE 45? Thanks for your inputs.

Edit: Excuse my old memory, because now I think I may have poised this same question in the past?