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EL34 PP amp build X2 - here I go again! (was 6L6GC) - Printable Version

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RE: Another amp build - here I go again! - MrFixr55 - 09-19-2025

Rich, I remember seeing a display of a missile that was cut away. In the head was a chassis with several 9 pin tube sockets. Obviously, every aspect of the circuit as well as the tubes were removed.

I never got the chance to go to "Radio Row" on Canal St. in NYC before it all was torn down in the late 1960s early 1970s to make way for the world trade center. that was the "Mecca" for all the WWII, Korean War and other government surplus. In addition, the GSA (Government Services Administration) held closed bid auctions.

I used to work for a guy who used to bid on cars offered by the GSA, either govt surplus, or confiscated from federal criminals, usually drug or RICO felons. (We won an Eldorado from a Capo in the Bonanno Crime Family, a VW with the fake Rolls Royce Nose and a 1968 e Type Jaguar (Oy was that a mistake) as well as countless GSA fleet cars and plane brown wrapper Federal Agent cars (Plymouth Fury 1s with 426 Wedge engines, Fords with 429s as well as more mundane transportation (Ford Fairlanes with power nothing, manual steering and brakes, no radio or AC and rubber floor covering instead of carpeting, non-metalic paint and the only chrome was on the bumpers.) By the 1970s, they started to have some options. The government fleet started to have a LOT of AMC Hornet and Matador (I supposed that they were trying to bail them out), and we bought and sold a lot of Ford Pintos (post gas tank recall) from the Government fleet. For the times, they were not bad cars, just small, tight and not comfortable for a big (read tall and fat here), underpowered, and did not get great gas mileage considering size, weight, number of cylinders and displacement, but these were all 1975 or later, totally smogged out.

RE: Another amp build - here I go again! - MrFixr55 - 09-19-2025

TV Man, You are fast becoming... AMP MAN!!! America's latest Super-Hero!!!

Back when Mike Huckabee had his own show, they had his wife on and they played "The Newlywed Game", where they asked each spouse (in the absence of the other) questions and were graded on the number of matches. they asked Huckabee how many guitars he had; he said "25". When asked the same question, Mrs. Huckabee said "Too many". Of course, the judges judged the answers matched.

I would bet that for almost all of us, we can probably answer the question "How many radios, TVs, amps, etc. with a concrete number (or maybe not). However, I would bet that our spouses, kids, significant others, etc. would all have the same answer- "TOO MANY!!!"

RE: Another amp build - here I go again! - TV MAN - 12-07-2025

Just a quick update: I have both amps pretty much completed and been listening to them every chance I have. I'll post all the gory details and changes along with my final schematic drawing once I put the bottom on. There's still some minor changes I might make like moving the bias adjustment underneath accessible through a hole so someone doesn't mistake it for a volume control or something. Also a pot to adjust the brightness of the indicator light. One MAJOR change I made was using EL34 output bulbs instead of 6L6GC. I was having problems getting much more than 32-35W with those and a tube rectifier, whereas I could easily achieve 40W with the EL34s. It DID sound GREAT with the 6L6s, but lack the drive needed from the voltage amp. I did experiment some with adding a tube between the pentode and inverter, but didn't work well at all. So, as it is, it sounds strong and clean. It's simple. So far, been working great. I'm inclined to close it up, do a final write up and call this one finished. I have the stuff to do another using the Mullard circuit or similar to get the drive I need for the 6L6s. 

Now - I CAN get a full 50w using the EL34s IF I plug in the solid state rectifier. It raises the B+ by about 20-25v, but I already have it set up for the tube. So, it stays. I'm gonna leave it alone. Better to start a new build later.

RE: EL34 PP amp build X2 - here I go again! (was 6L6GC) - TV MAN - 05-25-2026

Just bumping to keep this alive.