ARC REF10 PS

[cygnus x1]

Hi all,
Has anyone seen a schematic for the 6550/6H30p/Fet power supply used in the REF10/REF3/PH9, or a DIY version? I have and older PH3 (that I'm converting to a PH5) I would like to add this PS...to keep the ARC flavor.
I take it the 6550 is the pass tube, the 6H30p the control tube ...but the Fet ... part of the control circuit?
Anyone know where could I find a R core transformer?

 

[ticknpop]

Lots of R core on Ebay, just be carefull which voltages when you see the selection options

 

[analog_sa]

Drawn from a Ref 3 pcb more than 10 yrs ago. Opamp likely different from the one shown.

 

[cygnus x1]

I know there was a 6L6 upgrade to a 5881? Not sure what a 6550 would get me other than increased current (along with using a higher current power transformer). The REF 3 supply should work fine. Do you remember the output voltage? Of course I can just build it to find out.

Thank you very much!

 

[analog_sa]

I believe it was about 180v.

Soundwise a Salas regulator + choke input + valve rectification walks all over it, but of course just imho.

 

[cygnus x1]

I agree the Salas regulator is one of the best. I plan to use dual-mono BIB regs for the Fet diff-amp input stage of the PH5.
Could I use a AD797 in place of the OPA134? It's a lot quieter.

 

[johnmarkp]

I have used both the ARC and Salas HV regulators powering ARC Ref 3/5 clones. I would use the Salas regulator in any new project. I do not hear as much of a difference as others. The Salas is so much easier and less expensive to implement. It takes up a lot less room as well.

 

[analog_sa]

Looking at the circuit in post #3 it appears the + and - inputs of the opamp are shown the wrong way. No idea how this has happened.

Opamp noise is hardly an issue at these voltages and while different opamps will sound different the AD797 will likely cause oscillations.

John, have you built the circuit above? I distinctly remember myself building it, but have no explanation why is it wrong as shown.

 

[johnmarkp]

Not sure how that happened. The pin numbers are correct. I never paid attention to the + and - symbols. The older and slightly different supply for the Ref2 mkII uses a OPA176. The pins are the same as I used. It adds a 1.44k resistor to ground from pin 6 of the opamp.