On January 21, 2014 at 08:42, Ernie Gilman said...
I have no interest in having any of that stuff, as I'm more than full up right now.
It's interesting that the rectifier is an 80, which is a four-pin tube, while the others, IIRC, have octal plugs. I've never seen a mix of types, but that's just the equipment I've run into.
The best receiver I ever had was a Philco TRF receiver with four stages of RF amplification. Imagine this -- in the thirties, they had made a radio where four RF amplifiers tracked each others' frequencies well enough to select a station with no audible background sound from another station!
What brought that to mind was that none of the tubes had octal sockets. There was the 80, and tubes with five and with six pins.
That radio had a couple of tubes in it indicating that they had been installed as replacements in 1937. I put about 25 feet of wire on its antenna terminal, connected ground to ground, and here in southern California I got WWL in New Orleans and WLS in Chicago. I regularly and easily got KOA in Denver and KOB in Albuquerque; some station in Norman OK; and I heard The Ballad Of Billy Joe for the first time from some dank dark outpost of semi-civilization in the South.
All this radio listening was after midnight on Sundays, when all the local stations were off except for occasional testing.
The 80 matches 5Y3 in performance but another 4 pin rectifier was the 83, which used mercury vapor and had a blue/purple semi opaque glow. I know of one guitar amp that used this briefly in the mid-'50s, but they switched to GZ34/5AR4.
For the 6Q7G and 6C8G, octal sockets aren't enough- they each have a second cathode attached to a button on the top of the tube, with an aluminum sleeve/cover over the whole. tube. I think the use of octal sockets was just due to those being available and it was preferable to use one part, rather than making a specific socket for each tube and then needing to replace it when a tube is discontinued.
I was looking at some old items and one radio (don't remember the brand, but it may have been a Crosley) had tube numbers like 23, 26 and 27.
Amazingly, when I looked on ebay for a replacement rectifier, it was very easy- I bought three of them for $18.50 and the first one I tested worked fine. Using the tube data from the TDSL site, I was able to feel comfortable when I inserted each tube by verifying B+ on each of the previous ones. Then, there was the disappointment in hearing almost nothing when I inserted the cable and touched the tip. I had installed the tubes in the same positions as I found them, but after checking the data, I found that V2 and V3 had been reversed. Once that was corrected, I had a nice, extremely old, working amp.
I think the original owner took the tubes in for testing when the rectifier died and decided that they wouldn't replace it, so they put the tubes back and stuck it in a closet. At some point, someone's kids used it for target practice with their BB gun, but there's minimal damage from that. I don't use it much because I want to keep the original speaker intact- they used hide glue for assembling the cone and it becomes very brittle. It's a Rola K100 and has the field coil you referred to, earlier. It's very noise-free, too.
