Transel Dynamite 150 reverse pre-amplifier on the bench, undressed, Amp Porn.

[@bblod4896]

I've been restoring my first TV. A 1972 Sears 12" B&W tube TV. The tubes are still good but the electrolytic capacitors were done. I replaced them and brought it up slowly on a variac. I have a bright screen but the receive is very weak. I started measuring the carbon composite resistors and ALL of them are way out of spec. I've started replacing each resistor until I ran out. I'm currently waiting for the rest of the resistors to complete this project.

[@tramdr]

That is common too, especially in Tube Radios, not as much in amps, but still something to look at. My guess as to the reason why is TV's and Radios were on a lot, cooking the resistors. Amps were usually on a fraction of what a radio or TV is. I once did up a perfect Tram D201A for a local bud. He left it in 24/7 for a year. He then gave it back. Man, that thing was an overcooked Goose.

[@bblod4896]

@@tramdr I agree with the cooking theory. 👍

[@joeyTR21X]

Great video. Nice amp for a good talk on my old 1978 Cobra 148. Very nice....

[@tramdr]

Thanks!

[@bucketofguts]

Needs some cool cut class lights for a little bling. Sounding good!

[@thesquirrelchroniclesakare7808]

Turned out great Doc 👍🏻

[@tramdr]

Thanks!

[@bblod4896]

Nice restoration on your amp. It does exactly what it was labeled as, 150 watts peak. I have another saying you may have heard: Mechanic "A" asked his fellow mechanic "B" what was wrong with that customer's car, mechanic "B" replied "loose nut behind the steering wheel". 😂

[@tramdr]

I was a weapons system mechanic and radar tech in the Army. We also used to say "The Operator Head Space"

[@keithweiss7899]

I thought that you had a linear with a reverse preamp on it, like the Bandit. It used the power output tubes as a preamp. Didn’t work so great. It was very noisy! Btw, my Elmer took his Bandit and took out the junk preamp. He put in a transistor keying circuit, so the noisy switching power supply wasn’t needed on all of the time. Then he took out the HV power supply and replaced it with an army surplus Dynamotor. It worked great!

[@tramdr]

I've had a couple like that. I think Elkin was one. It was actually pretty good, the Tune and Load for the output also tuned the preamp input.

[@nomadradio]

Grids are ground for RF. The disc caps from the grids to ground are a RF ground. Just not a DC ground. Still qualifies as grounded grid cathode driven.

[@tramdr]

Not the screen grid though with 250v on it.

[@nomadradio]

@@tramdr Um, the screen grid had better be bypassed to signal ground with one or more capacitors. Same as the control grids need to think they're a ground for signal voltages even when there is a DC bias on them. The screen grids can become a feedback nuisance if that bypass cap isn't there.

[@nomadradio]

@@tramdr Okay, plus 250 DC on grid # 2, and negative 8 or so on grid number one. Both must have bypass caps to ground. Makes either grid an effective ground for signal currents, just not for DC. Leave that bypass off the screen grid and risk feedback headaches.

[@tonylewis7277]

Tram Touch the lights with Screen driver.fuse under the bottom of The Wire. Our other fuses are good. No sound, can you help.

[@giuseppecuffaro-1398]

Hello sir i got a nitro 300a with bab capacitor which one would you recommend me to use for repair please help me?

[@tramdr]

Replace all the electrolytics in the amp. I would use these 500v caps as that amp ran about 430v across each cap if I remember right, and they kinda rate voltage on caps different than the old days. There was a time many caps were rated with the voltage by the continuous working voltage. However, nowadays, most caps are rated for intermittent peak voltage. Also, those big ole can caps are pretty much obsolete IMHO though some may disagree. I would carefully replace the old cans with modern snap in caps. These are not the best, but at least the seller is in the USA and the price is right, plus with the 500v rating instead of the common 450v, I think they will last. I try to avoid these type of questions because so many people have so many different opinions. Kinda like asking what oil to put in your car, or what tires should I buy. Also, the Transel amps are a little weird and tricky. Not for a Novice to play with, IMHO. www.ebay.com/itm/163651457878

[@giuseppecuffaro-1398]

@@tramdr 73 sir and thank you very much

[@jamest409]

How are you tramdr friend, still sounding shall I say Tired?

[@tramdr]

Still feeling old and tired. Feeling my age more and more. Having a lot of Sr. moments too. However, I am currently not sick!

[@jamest409]

Me too