Will this work by itself?

[Sadface]

G'day Guys,

I salvaged an old Sony home theatre receiver recently for parts.

I am wondering if I can re-purpose the rear channels into a stand alone amp.




I don't really understand the uPC2815v IC and I cannot find a datasheet.

The bit that gets me is the 'NF' which I take to mean negative feedback.

Am I correct that this board will NOT work by itself without a driver?

It looks to me like I need to either resuse the uPC2815v IC or make a new balanced out preamp and nest it within the negative feedback loop.

 

[amplidude]

This might help,
It's a class a predriver

 

[Mooly]

The IC is 95% of the two channel power amp. The 'rear board' if you take away the protection bits and bobs is just an NPN/PNP output pair bolted on to the chip.

Yes, NF is negative feedback and taken from the output of the transistors and fed back into the chip via R503/553. All totally conventional topology.

 

[Mark Tillotson]

I'm not sure how the biasing works - the pre-driver block diagram has a bias part, and two wires carry the signal for each channel to the power board, but there appear to be bias compensation transistors on that board mounted on the heatsink, presumably one of the ones labelled "limiter" for each channel?

 

[Sadface]

Thanks guys,


I was afraid of that. It looks like this one is going into the too hard box for a while.



If I ever get bored I might remove one of the uPC251 ICs from input board and replicate the circuitry around it onto a small stand alone pcb.