Voltage Doubler Supply

[highendman]

I'm making up supplies for an opamp based phonostage. The transformer in my inventory is an old Avel-Lindberg 12V+12V/4A. I'm going to use the super regulator boards from the DIY store (it's too bad they broke the board in two, requiring twice the mounting).

Initially, I was thinking I'd like to use RC-LC-RC filtering, then into a 1085 (17.25V), then into the super regulator boards 12V.

A few questions:

Is it possible to stack the voltage doubled supplies?

is it beneficial to add the 1085 regulator prior to the super regulator?

Would it be worthwhile to add opamp regulation (Curcio stye, seen here The AN1651/Curcio Phono Preamp | Orion Gateway), after the super regulator (then omit the sensor leads on the super regulator)? This looks interesting to me and I thought of giving it a listen, as the investment would be mostly a fistful of resistors.

I noticed that using PSU Designer II, it's possible to get down to .001V accuracy from RC-LC-RC filtering that I have on hand (with the voltage doubler supply).

Thank you.

 

[jan.didden]

Opamp regulation after the super regs seems not a smart move. Either the super regs are better than the subsequent opamp reg, and then you are better off deleting the subsequent opamp reg.
Or the subsequent opamp reg is better than the superregs, and then you are better off deleting the super regs.

jan

 

[highendman]

Thank you for the input Jan.

Any idea about stacking two supplies from voltage doublers?

 

[counter culture]

You can voltage double the stacked secondaries.

 

[highendman]

Thanks counter culture.

Experimenting with PSU Designer II, showed me that you can get some unusual results with the voltage doubler circuit -- like huge voltage and current spikes across the first two filter capacitors. I was seeing spikes of 1200V in the first moments after powering up. Small resistors seem to eliminate this effect.

I plan on using the doubler circuit so I have some room to work with, rather than starting with 16.9V. I know that the super regulator runs optimally with at least 5V headroom.

 

[jan.didden]

The question is then, would it not be better to skip the 1085 and not use the doubler? That should give you enough headroom for 12V (5 V is not really required for the sreg; a couple of volts will be enough).

Also,the large xformer will most probably provide much more than 12VAC because it is lightly loaded.
Why don't you just rig up a reg and some caps, with a resistive load that takes as much current as you thing the circuit will take, and look what you get?
I'd bet it will be much more than you need.

Jan

 

[highendman]

Reasonable advice Jan. Thanks again.