• 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.

line operated design.

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I thought this one up last night.

I don't know the values for all the stuff, and I know the 50L6 isn't very "hi-fi". Now I need some low Z tubes and I can figure out some kind of completely transformerless design....

Anyhow, I know it's evil and a deathtrap. Just thought I would share it anyways:eek:

Any thoughts?


edit: forgot to put the "only one channel shown" deal in there.. wont be able to run it off the wall with only one channel..
 

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Here's a circuit by Steve Bench that avoids the "death trap" rap - http://members.aol.com/sbench/50c5.html

He uses an input transformer to isolate the circuit from the line. The grounded power cord and grounded secondary of the output transfomer make this "safe enough" that it could pass the current UL or European safety standards.

He says 3.5 Watts, but it would do more into 4 or 16 Ohms - though it might not be flat down to 20 Hz any more.
 
paulb said:
I worry about posting stuff like this without a huge warning over top of it. You'd be surprised what people will try to build.
Or post away and call it evolution in action?

hahaha.. should be ok if you use a polarized plug, and check to make sure the house is wired right.. :D

I think I forgot to put in some grid leaks.. hmm..
 
yeah, that sounds like a decent idea.

I'm working on winding an OPT for my PSE 6V6 deal right now, and all i gotta say is.

so boring !

i really need to mechanize this if im going to finish it.. maybe put it on a dead turntable or something..

this iron might be a little on the small side too.. oh well, its just for kicks, not for hi-fi:D
 
frugal-phile™
Joined 2001
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Circlotron said:
Add a second rectifier tube to make a voltage doubler rectifier. 100 / 120 Hz ripple, nicer to the mains, and twice the plate voltage. :)

In the 50C5, 50EH5 amps i am using these in, i use a SS bridge (gotta keep the filaments adding to 120V). These tubes were designed to run off not much more than 120V. I'm not sure about the 50L6 -- although i do have one of those in the parts pile.

dave
 
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