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    Building, troubleshooting and testing of these amplifiers should only be
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    the safety precautions around high voltages.

6J5 or 6S4 mic amp?

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Simple mic amp

Simpler yet would be to use a 6eh5 and 12ax7. Filaments can run off a cheap 6v 1.5A RadShac tranfo, and B+ can use couple of wallwarts connected as Isolation transformer.
The 6EH5 will be happy at 110-120vdc @1.5w output, and is about as simple a circuit as I could think of. Schematics for this type of amp are available in the circuit section of old RCA tube manuals, RC20 I think.
They are available as complete free download from pete millett's site.
"THANKS, Pete for all your hard work!" 🙂
 
Unfortunately, i do not have either of those tubes, i do have these though:
Code:
117p7 ?
12at6 good
12at7 good
12at7 good
12au7 bad
12au7 good
12au7 bad
12au7 bad
12ax4 good
12ax4 good
12bh7 weak
12by7 good
12cu5 good
12cu6 good
12sk7 good
1b3 good
1ln5 good
3q5 good
45 ?
5an8 good
5aq5 weak
5aq5 bad
5br8 good
5t8 good
5u4 good
5u4 good
5u4 weak
5u8 good
5u8 good
5v6 good
5y3 very weak
5y3 weak
6ac7 good
6ag5 good
6ag5 good
6ag5 good
6ah6 good
6al5 good
6al5 good
6al5 good
6al5 good
6al5 weak
6al5 good
6an8 good
6as5 good
6au6 good
6au6 weak
6au6 good
6av6 very weak
6av6 good
6av6 good
6av6 bad
6aw8 good
6ax4 good
6bq6 / 6cq6 good
6bq7 good
6cb6 good
6cd6 good
6cd6 good
6cg7 good
6cg7 good
6cg7 good
6cg7 good
6cg7 good
6cg7 weak
6cg7 weak
6cg8 good
6dq6 good
6j5 good
6j6 good
6j6 good
6j6 good
6k6 good
6s4 good
6s4 weak
6sh7 good
6sl7 good'
6sn7 weak
6sn7 weak
6t8 good
6u4 good
6v6  weak
6v6 bad
6v6 weak to good
6w4 good
Pšÿÿ
 *** END : 86 items sorted ***
Thanks for the suggestion anyway.
 
Where is the picture I put in my profile? I geuss it needs to be approved.
Anyway, like somebody said in some other (old) tread I found when I was looking for something else (tube FM transmitter? ore something), you won't learn anything you can use somewhere else from doing this. But if you want to do it then go for it.

Jim
 
you are working entirely the wrong way around.

The expensive bit is the OPT. Start there since it dictates your output tube selection anyway. Then figure out the output tube - you have a few to choose from. Then your voltage amp - again, you have some choices in your stock. Finally, your PTX to supply the design, not the other way around.

The rest is passives and other stuff you know about...
 
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