35khz High Frequency AC Supply (Tube design)

[CivicProtection]

I made a previous thread where I got alot of generious help in regards to making an IC/transistorised AC generator, but I think for my mag-amp project at tube type powersupply would MUCH more simple and apropriate. I copied this basic schematic from an article which detailed mag-amp theory and practicle applications of such technology.

Imageshack - powersupplys.jpg

It is the ideal powersupply for it, because it is designed for it.
However, I don't know what kind of tube, inductor, ETC to use because there is no parts list.

For my mag-amp supply I would like to eliminate the tube alltogether from the schematic and replace it with a rectifier, but it has a center tapped transformer and coil connected to the pentode type tube that I am not familier with.

Can I assume that the tube heater element is running off of 110v mains?
Then what are the grids attached to, what is that coil sitting nect to the tube for? And why is the transformer the the right of it wired like that!?

I'll go with the tube design if I have to though.
Once this HF supply is done, all the rest will fall into place.

[godfrey]

That looks like a very weird (but not wonderful) oscillator. It would be better to run it off DC rather than AC. I think the tube is a double triode, with the common cathode in the center. The coil on the left should probably be coupled to the transformer on the right, unless it's relying on plate-grid capacitance for feedback.

Anyway, to build something you need a circuit with parts values, and to generate the high frequency AC electronically, you need an oscillator with some kind of active device e.g. transistor / tube / mosfet.

The other option is to go for a mechanical solution e.g. a motor-generator or something involving motor-driven rotating switch contacts.

I suspect that folks who understand SMPS could find a neat way to extract the required HF power from a butchered computer PSU.

btw, I'd recommend running the amp at a much higher frequency than 35khz to ease the filtering.

The POC magamp at sparkbangbuzz is deceptively simple. What's not obvious is that the output is full-wave rectified 35khz AC, so the speaker's being fed more DC and more 70khz than audio.

You can probably get rid of the high frequency ripple with filters but sorting out the DC will require some major re-design.

[CivicProtection]

Originally Posted by godfrey

That looks like a very weird (but not wonderful) oscillator. It would be better to run it off DC rather than AC. I think the tube is a double triode, with the common cathode in the center. The coil on the left should probably be coupled to the transformer on the right, unless it's relying on plate-grid capacitance for feedback.

Anyway, to build something you need a circuit with parts values, and to generate the high frequency AC electronically, you need an oscillator with some kind of active device e.g. transistor / tube / mosfet.

The other option is to go for a mechanical solution e.g. a motor-generator or something involving motor-driven rotating switch contacts.

I suspect that folks who understand SMPS could find a neat way to extract the required HF power from a butchered computer PSU.

btw, I'd recommend running the amp at a much higher frequency than 35khz to ease the filtering.

The POC magamp at sparkbangbuzz is deceptively simple. What's not obvious is that the output is full-wave rectified 35khz AC, so the speaker's being fed more DC and more 70khz than audio.

You can probably get rid of the high frequency ripple with filters but sorting out the DC will require some major re-design.

Well, my target output would be 35 khz at 12-15 volts AC. I'd been givin some advice from a person over in new mexico that a LC tank circuit would work. And that he himself would take a 12v DC input and convert it to HF.

[CivicProtection]

Any more ideas please folks!? Non transistor, non IC, low voltage HF AC generator @ 50 khz output.