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In Reply to: RE: Most popular SET amp posted by mark.korda@myfairpoint.net on May 08, 2015 at 12:11:44
Dunno about the rest, but I'm pretty sure that old radios were SE because tubes themselves were really expensive.
Follow Ups:
More bang for the buck. Less expensive transformers required with PP.
Many console radios (pre WW2) used a pair of output tubes such as the 45 or 2A3 to deliver something like 4 to 6 watts push-pull.
I have found lots of old radio photos online, but not much on SE vs. PP.
Any antique radio experts out there?
I don't think push-pull came into widespread use for consumer audio until well after the war. Even at that, the great majority of tabletop radios I've seen from the '50s and '60s were single-ended.
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Buy Chinese. Bury freedom.
In 1928, we still had SE 205 amps from WE plus SE 210 and 250 amps from RCA. However, push-pull amps also appeared in 1928, with much larger numbers of pp by 1929. Of course, the "large numbers" of folks back then were first discovering the sound of the airwaves as well as the sound of amplified phono or reproduction. Public address was also developing very quickly...
Make no doubt about it, though, the birth of hifi was born by the transformer companies. Retrofitting better grade trannies to your "radio outfit" guaranteed "better...more realistic sound" according to many ads of that era. Every major USA tranny manufacturer offered kits and/or high grade parts by 1928. I have some 1928 trannies that are absolutely high fidelity; even by today's standards. These units I speak of were available for consumer home hifi; not necessarily commercial usage. Most of these published amp schematics offered by tranny companies were already push-pull in 1928. By 1929, besides the few "known" SE classic amps like Loftin-White, RCA or WE, Push-Pull was well established as the norm...
The WE 42 and 46 theater amps appeared in 1928; both used PP 205. WE's 205 tube was closer to a 210 by RCA, compared to RCA's 245 or 250. I have always found it very interesting that any development by RCA or WE was soon mimicked by the other. While the VT-1, 101, 102, 104, and VT-2 WE tubes are considered their "earliest" studio or broadcast line level or opt tubes, RCA had their UV-199 and UV-202 at the same time period as the WE VT-1. WE also had a thin input tube similar to the RCA UV-199. Line level and preamp tubes by WE were not much different than the venerable RCA UV-201. The RCA UV-202 appears as the WE VT-2 appears. When the RCA 210, a development of the UV-202 flourished, the WE 205B tube appears.
While TK is right that tabletop radios were still the hold-outs of SE for a few more decades, as of 1930, there were very few SE amps offered with hifi in mind; especially to the public. BTW, the WE 300A and WE 91 came about in the early 1930s; after the RCA 250 tubes and amps. By 1933, the WE opt tube of choice was the 300A; while RCA offered the single plate 2A3. 1933 is also significant as the demise of GL globe/balloon (and tennis ball) shaped tubes. Most interesting, is the fact that all RCA tubes were always offered to the public (consumer), while the WE tubes were not offered to normal consumers. WE tubes could only be purchased from certain distributors; usually reserved for studio, broadcast and theater contractors and engineers...the early "soundmen" as we fondly speak about...
Maybe most of the 1930's console (floor standing) radios were push-pull, while the majority of tabletop radios were single-ended.
No doubt about the sound quality, though.
Tom, others
Most of the radios I worked on here were either 45 or 71A single ended, only a few 2A3's. Most of the early RCA, Crosley and other bakelite units were single ended. I don't remember any of these being pp.
But they are not really hi fi either. The outputs look like they are good to like 80hz, like most guitar amps that are single ended.
I did have a cool japanese radio that had line inputs, silver mica coupling caps and ECL82/6BM8 output tubes. It was really sweet and someone had to have and I have too much junk here already.
The WE stuff early on was not sold to anyone. It was all leased and WE and then Altec serviced all the equipment. They put those damn 91A amps in almost anything. I was called ounce from some guy who was redoing a house here in Cincinnati (Lindner's) they had a PA system in their house run by 91A amps. Hadn't been used in years, scored a couple and a boat load of 300B's, 274 and other tubes.
Thanks,
Gordon
J. Gordon Rankin
Hi, great answers and info! Thanks you guys...Mark
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