Voltage doublers.

[al newall]

I have a mains transformer that's doing nothing, but with a voltage doubler could be used for a tube preamp.

Are these okay for this application, or best avoided?
Don't have the funds to go out and buy the ideal transformer.

[Mike H]

More details?

It will be like single-phase rectified, but should work. Best if circuit current is small compared with transformer capability.

This is a detail of my stepper pre-amp PSU if it helps, imagine the -18V line is ground for your kind of application, so I'd think of doing it like this

[al newall]

Yes, something like that is what i have in mind.
I was wondering if voltage doublers are noisy compared to the usual supplies. ie. good enough for a pre amp.

The transformer has a 124v secondary, and is from a Chinese El84 PP amp.

Just want to run a pair of e88cc or 6n1p, and play around with cathode followers, without pinching bits from my usual amp.

Does it matter what value caps are used? The diagrams don't usually specify anything other than maybe the voltage.

[Nick]

Steve used one in his latest AFAIK.

[Mike H]

Yes, something like that is what i have in mind.
I was wondering if voltage doublers are noisy compared to the usual supplies. ie. good enough for a pre amp.

I would expect, depends how much ripple. Ergo I said would be best if PSU is 'lightly loaded'

Just want to run a pair of e88cc or 6n1p, and play around with cathode followers, without pinching bits from my usual amp.

Should be possible I think, only one way to find out!

As regards caps, I would say large values?

[Cressy Snr]

I used a voltage doubler in my preamp and it is quiet. It is only lightly loaded at around 36mA from a 300VA transformer.

[al newall]

So it's not a bad idea then!

I'll wait for the next bout of enthusiasm to come along, and then get cracking.