5000V output amp build help

[LazyDoorMan]

I’m building a custom Voltage amplifier that will be amplifying “pure” sine waves from a signal generator. Input signal will range from .01V to 1V and will be a set frequency ranging 500-5000hz.

I’m new to tube amplification. I was originally going to wing it and just use a 5f1 but thought I’d maybe put some more thought and not just outright waste money blindly. So I bought a book “Amplifying With Vacuum Tubes” by Carl Gauss. I’ve read and reread it about 4 times, and I’ve learned quite a lot, but I’m still short on knowledge in a few places.

Currently I don’t have any parts other than a signal generator and an o scope on the way.

The signal generated by the signal generator .01V-1V (it’s a cheap FeelElec FY8300) needs to have a final amplification factor that will bring the signal to 5000v or more. This signal out is a broadcast antenna Containing multiple coils in series. I’d like the final sine wave signal to have as least distortion as possible.

Here is my custom design I’ve designed. It includes cathode biasing, 1M pots all over to help refine the signal. I’ve included a similar B+ filter as the 5f1 however I’m not sure of the C7,C6,R15,R14 values. I think I’d prefer to use a choke filter instead bc I’m under the impression it will aid in less distortion, but I don’t know how to determine values of L1, C55B.

I believe with the 12AX7 and 6SN7 I should be able to achieve a 250V signal and then amplify it through a microwave transformer at a conservative 1:20 ratio to achieve 5000V. I’ll be using the 5Y3 rectifying tube. The OT is me thinking outside of the box to achieve my goal..... is the coupling at C5 as well as the 1M Pot load at R13 going to be sufficient to ignore the usual impedance requirements that are necessary to work around with most OT and still allow strong low distortion voltage gain though the OT.

Lastly, I’m not afraid to start the design over from scratch I’m just a newbie and this is my newbie design in dire need of external input from those who know much more than I do.

As a side note.... I’ll be building 3 of these units, so cost is a factor within reason, but I understand the need to spend what’s necessary.

Thanks

[Stevem]

You might as well add to your parts list a custom door mat that says welcome FCC because they will be paying you a vist in short order if you reside in the US!

Are you by chance related to Nicola Tesla?

[Colossal]

Welcome!

Good job reading up and getting the basics down. 5kV is going to be right on the edge of ionization potential of air, so, depending on your currents you may have issues with ozone production and insulation breakdown. You should also think about some kind of flyback protection on the primary side.

If you transmit, you will probably get triangulated by your local radio amateur's group and, as Steve said, paid a visit by the FCC

What are you up to anyway? Are you building your own Wardenclyffe Tower?

image.jpeg

[sluckey]

Way ahead of you ClazyDoorMan. Built it in '67. Spark gap signal source could be heard throughout the school building. 10" free space arcs! Research Popular Electronics, July 1964 issue.

[LazyDoorMan]

I’m not trying to get my door kicked in or break any laws lol my description of Antenna has got people freaked out. The antenna that the signal will go to will be inside of a motor housing connected to one phase each of an induction motor. The coils are the antenna. I used the word antenna to help explain the nature of the output not requiring amperage/power. The design is strictly precision voltage amplification. Not power amplification. The final 5000v output would preferred be lower than 5w but closest to 1w would be preferred. The signal won’t be being broadcasted over the air or whatever.

[LazyDoorMan]

Texas Instruments has a controller that runs an induction motor using RF signal. However, their programming will max out at 600v and 1500hz ish if I remember properly. Reverse driving the motor and pulling out it’s parameters displays a direct need for frequency at voltage all the while using mere mA. Sooo.... i thought I’d do an old fashioned thing and do a dangerous experiment in the name of discovery and see what happens. This “sonic “ motor is utilized all over every day but it’s limited by the voltage and frequency of its controller. So I’m building my own extremely high voltage controller piece by piece with age old technology.

[LazyDoorMan]

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

[roberto]

This should help you. It's what I use to drive SE amps with one single stage.
From 1Vp at its input you can get 200Vpp at its output with around 0,5% THD.
Instead of the CCS, you can directly drive it with the primary of the coil and be able to swing above B+.

SE-Driver.jpg

[bepone]

I’m building a custom Voltage amplifier that will be amplifying “pure” sine waves from a signal generator. Input signal will range from .01V to 1V and will be a set frequency ranging 500-5000hz.
Thanks

the schematic cannot work properly,
- all the tubes are supplied from one point searching for oscillation and instability, it need 1 more RC decoupling stage to the firststage
- low impedance secondary of the transformer will be driven by 6SL7? with low distortion? i doubt so, this will be too low load for the too big ouput impedance, more like dinamical short circuit
- low impedance secondary can be driven by SRPP stage which is made for this , per example, to be checked Philips SRPP documents with EL86's
http://www.r-type.org/articles/art-146.htm
https://audioxpress.com/article/The-SPP-Amplifier

[Stevem]

You might want to try and turn up some old computer CRT type monitors to toy with at first since there Horizontal output stage could easily produce 5KV.

Old color TVs that used CRTs and had 25” screens had Horizontal output stages that could top 24KV and I recall all to well getting hit by that voltage when I forgot to discharge the screen when removing the sets chassis’s for service!

[martin manning]

If I may ask, what is this thing for? Does it have anything to do with a guitar amp, or even making music?

[Phil_S]

If I may ask, what is this thing for? Does it have anything to do with a guitar amp, or even making music?

I'd add, this turns out to be among the most entertaining off topic threads I've seen. I wasn't even sure it would get any traction here.

[LazyDoorMan]

I’ve explained my objective in earlier posts. But for you I’ll go the distance. It has everything to do with a guitar amp bc it’s a voltage amplification circuit which is what a guitar amp is in addition to a power amplifier. And music is what we listen to, but before we hear it it goes on a journey through amplification.

I’d say it’s definitely a tangent to the common threads here but nonetheless the same tech audible or not

[TUBEDUDE]

Many things use the same technology but do not serve the same purpose. Sounds more like a motor controller. Good luck.

[thetragichero]

If I may ask, what is this thing for? Does it have anything to do with a guitar amp, or even making music?

I'd add, this turns out to be among the most entertaining off topic threads I've seen. I wasn't even sure it would get any traction here.

you kidding? i've had my popcorn ready for this and the similar thread on el34world. you've gotta see the potential in things my friend