5000V output amp build help

[LazyDoorMan]

They moved my thread on el34world..... I’m new to the whole forum thing. I was getting annoyed at people blurting out discouragement and but Ive still got a few standing questions if anyone would like to chime in:

>>Is there a better second stage tube I could replace the 6sl7 tube with that is prone to less distortion? I’m trying to stear clear of power pentodes etc or tubes that require taps in the OT transformer. However if I end up swapping the microwave transformer for a homemade torus a tap would not be a problem... well it may be a point of leakage

>>Is there a minimum current that needs to be applied through a microwave transformer in order to effectively induce a signal through it? Or value of load*/resistance* minimum threshold?

>>A point I hadn’t thought of until everyone’s response..... if I can have a primary signal on the OT of 250v {with head room of course} @20mA (5W) transform to 5000v @1mA (still 5W), will I be well in the clear of not disturbing the air space and stay within the realm of legality? I ask bc I fr can not afford to pay a federal fine.

Also, the frequency operation of 500-5000hz is still the same but it might be important to know it will for the most part operate on the high end of that spectrum from 3.5k - 5khz

[Colossal]

Colossal,

Can you explain the flyback you describe? What size and how do I connect it? I’m not sure I understand. Also, what is the trade off without it

Check out the schematic for the Trainwreck Express and search the forum for 'flyback'. You will see a series string of 1000V 1N4007 diodes from the power tube plates to ground, on the primary side of the (push-pull) output transformer. You would want to size these accordingly for your setup, of course. These would help provide some protection against tube socket arcing, as well as against an accidental, no-load condition on the secondary side.

[LazyDoorMan]

Thanks Colossal!

[bepone]

>>Is there a better second stage tube I could replace the 6sl7 tube with that is prone to less distortion? I’m trying to stear clear of power pentodes etc or tubes that require taps in the OT transformer. However if I end up swapping the microwave transformer for a homemade torus a tap would not be a problem... well it may be a point of leakage

did you check the links what i have posted one page before? this schematic will never work. you need to read a lot of theory and learn a lot, understand the problematic of your project .. gain some real practice, like building some simple 5W s.e. amp, like Fender champ per example. after some experiments and 5-10 amp / preamp builds you can develop some sense what you need to drive transfomers, what is limiting the freq. response, what are requests from the driver circuits.. etc etc

[TUBEDUDE]

They moved my thread on el34world..... I’m new to the whole forum thing. I was getting annoyed at people blurting out discouragement and but Ive still got a few standing questions if anyone would like to chime in:

>>Is there a better second stage tube I could replace the 6sl7 tube with that is prone to less distortion? I’m trying to stear clear of power pentodes etc or tubes that require taps in the OT transformer. However if I end up swapping the microwave transformer for a homemade torus a tap would not be a problem... well it may be a point of leakage

>>Is there a minimum current that needs to be applied through a microwave transformer in order to effectively induce a signal through it? Or value of load*/resistance* minimum threshold?

>>A point I hadn’t thought of until everyone’s response..... if I can have a primary signal on the OT of 250v {with head room of course} @20mA (5W) transform to 5000v @1mA (still 5W), will I be well in the clear of not disturbing the air space and stay within the realm of legality? I ask bc I fr can not afford to pay a federal fine.

Also, the frequency operation of 500-5000hz is still the same but it might be important to know it will for the most part operate on the high end of that spectrum from 3.5k - 5khz

Since it's your project, and you are the one with the project details, you are the one that has responsibility to insure any radiation from it meets FCC regs. Find a local radio station engineer, or a ham with an FCC 1st. class license to check it out with a spectrum analyzer.