B+ on UA (Universal Audio ) 610 Tube Pre?

rafafredd · Feb 4, 2015

I have one here with a blown up power transformer. As I am going to put another transformer in it, does anyone knows what is the B+reading on these units? I mean on the last tube plate, after the PSU, regulators, filters, or whatever. I have the schematics, but no B+ notes on it.

Thanks if anyone could help.

rafafredd · Feb 4, 2015

Maybe someone has one and could measure it for me???

pucho812 · Feb 8, 2015

can you trace the circuit and take measurements?

Ideally you should be able to work out what it should be?

I think I have some 610 notes somewhere. would you like original or reissue?

mitsos · Feb 8, 2015

Hinson said the original would have been around 300V, typical of the time. Anyway, what are B+ caps rated at? That should be a clue at least.

FWIW, Rick Chinn posted some info from his, but it was the LA610 MK II, with an SMPS supply. But his was 300V:

http://groupdiy.com/index.php?topic=47543.msg599154#msg599154

pucho812 · Feb 9, 2015

300VDC would make sense for the tubes used I can't imagine it being more then that

rafafredd · Feb 12, 2015

This is for a UA reissue, but the one with the original, Linear PSU. The Power transformer went BOOMMM, and I can't take any measures of the B+. Also, it has no specs writen in the trafo. I need to buy a new Power Trans for this.

So, 300v it will be.