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I've read recently about DIY projects making electrostatic loudspeakers (example). The membrane of the speaker should be supplied with bias DC voltage between 1 and 5 kV, roughly. There is virtually no current needed, only for charging the membrane.

With old CRT screens and photocopiers being short supply, how does one get such a voltage? Around here, only step-down transformers are easily bought, and I don't really want to be using any of those the other way around (effectively putting the rated voltage on the secondary coil).

I can imagine getting nearly 1 kV directly using a 1:1 transformer and voltage quadrupler, but this may prove inadquate. So the question is whether there is another way to get high DC voltage when I can't get my hands on an up-to-spec transformer.

Europe here, so 240V on the tap.

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So the question is whether there is another way to get high DC voltage when I can't get my hands on an up-to-spec transformer.

There is no option, you need to pass high voltage audio to the plates and this can only done using a transformer: -

enter image description here

The picture above shows your power amp (to the right) feeding the LV side of a step up transformer. The turns ratio is \$\sqrt{\dfrac{20k}{8}}\$ = 50:1 stepping up.

The DC bias supply feeds the centre tap of the HV secondary and to create that bias supply requires one of these: -

enter image description here

or maybe even one of these: -

enter image description here

Cutting thru and getting to the point, if you did not realize that you are likely to electrocute yourself - yes I know that's a generalism but this thing can kill you.

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There is nothing wrong with diode pumps for making KV .Low currents and high frequencies mean small ceremic caps Diode pumps work well on Boost convertors with the S TRAP switching loss reduction scheme .Also diode pumps work well on the self oscillating tuned collector pushpull invertor that is seen in LCD backlighting.I havent done this but I think that a camera photoflash invertor could drive a diode pump turning hundreds of volts into KV.Remember that there isnt really an upper limit .You dont need to stop on the quadrupler ,I once did a OCTUPLER.

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