Rega brio bias setting

[jimnich]

Hello everyone.

I'm new here so be gentle with me.

Recently fixed a dry joint on this "old friend" which solved an imbalance between channels. Somehow now sounds not quite 100%. Maybe needs to be re-biased? Has anyone got any information . I don't have a schematic or any knowledge of values or where to measure.

It is one of the first large clamshell models with the large feet.

Any help would be greatly appreciated !

 

[sreten]

Hi,

The clamshell Brio is based on a very old "Texan" design.

The power amp is an op-amp driving a CFP configured with gain.

See p4.pdf here : (and the rest of the pdfs)
http://www.diyaudio.com/forums/solid-state/54448-rega-brio-one-channel-dead.html

However there is a later larger clamshell (deeper) still with small feet.
Probably just doubled up output devices. Don't know a large foot version.

Whatever, identify output resistors and compare voltages
across them between the channels, adjust to match.

rgds, sreten.

 

[jimnich]

Hello Sreten,

Thanks very much for your reply. I will do as you suggest. I have only performed this adjustment on Sansui amps before . There service manuals are very user friendly. They always state a value in mv. I will post later how I get on.

Regards Jim

 

[jimnich]

Left ch = 22mv . rch = 60mv. Adjusted both to 20mv.
The output resistors were 1 ohm ( measured 1.3 ).
Suggested IQ 15ma.
Any way sounds as good as I can remember it.

Thanks Sreten. Regards Jim