• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Bob Danielak 826 Amp?

Tubefart

Member
2013-03-02 7:47 pm
I am seeking further info/construction details on Bob's 826 Amp. I would like to make a triode Se Amp that is simple, modest in cost and sounds neutral. His seems to fit based on(only) schematic, but unable to get any further. I am also worried that these tubes get gassy if fed less than 500 volts. Bob's uses 380 volts. Has anyone made this? what about his plate voltage? I have two RCA 826 tubes. I am new to site, but not to electronics. I can work from a schematic. I have a Dynaco PAS-3 Pre-Amp that I can upgrade for FM,CDs, Records & Tapes.
Many Thanks. Nick
 
Hi Nick (ya old fart :D), It's to bad you can't pick a better tube. I say this because, as you may alredy know, any that you find willl be very old. And very many will be gassy or have gone to air. For some reason the glass to metal seals weren't very reliable or trustworthy. I don't think it has much to do with lower plate voltage being used. Although you should get the plate a dull red. Having once been in the surplus tube business, I've possessed and sold many of these in an earlier life and can attest to their vulnerability. They were once considered a good UHF power triode. I've never heard them as an audio amplifier. Perhaps they are similar to an 808, but which have the same age and gas problems. Have you tried lighting the filaments yet? If they don't go up in smoke, you're halfway there.
 

Tubefart

Member
2013-03-02 7:47 pm
Tu-BEE or Not

Thanks Hollow State! You are from my favorite state of 'real" Hoagies. I lived in Glendora.. Well my Dad was a TV repairman and I had these or a bunch of 6L6s to select. I think these are like 808 tubes. Based on your knowledge & what I read, I will pass on these. Do you have any suggestions for getting 5 watts without taking out another mortgage? The majority of his tubes are for TVs. he stated he found them more challenging than amplifiers.

I do not have his expertise, I do this for myself. I do have 2 Masco amps and 2 Radio Craftsman 500s and 1 Scott 340 Receiver, but think now SET is the way to get natural sound. ???:confused:
 
Nick, I live in Northern NJ, Essex county. Caldwell to be exact. Your father was right. Television is much more complex then audio. The composite video signal is (or was) virtually the most complex waveform in electronics. I was a TV tech for many years, but got out of it long before it went digital. I started when I was a teenager.

6L6's will get you five watts. Even the old metal ones. And they are still made as 6L6GC I think. But you'll need to use them in pentode mode. You might try 809's. They are easy to drive and don't require that high a plate voltage. I've always been a push-pull man because I need power for inefficient speakers like Dahlquists, Vandersteens or Maggies. I also like SE sound but the right speakers are imperative.
 

Tubefart

Member
2013-03-02 7:47 pm
Ok, I prefer South Jersey. Never been "up north." I stayed away from TVs-Way to complicated for me. Don't know the 809, but thanks, will research it. Do 6L6s etc. in this mode REALLY sound as good as a straight Triode? Seems like to get any power out of triode you need lots of Power. Thanks for this lead. Nick