The PHILCO Phorum

I was thinking the same. There are many +12 Ground to -12 polarity converters in the market (mainly for old cars) but not one like that. I would even take +12 to-12 converter.

I thought this Sanyo chip is probably not necessarily positive ground. I can see the legs where the L and R channels are coming out. I can bypass the headphone amp they have built in. But what can I use for a ground? Would the chip's negative supply be the new negative ground. I got stuck there.

In a Yamaha receiver, the same chip is used with a negative ground. I have schematic for it but could not find one for the Sanyo.

Hello Toptip,
First all what is the IC part no . and what is the sony model number ?

Sincerely Richard

The chip is Sanyo A3311. It is obsolete, I could not find a data sheet for it. All my information is from a Yamaha CR500 receiver where it was also used.

The Sony? If you mean Sanyo, it is called RB9000. There are two versions of it, with and without a headphone permanently attached.

Toptip,
Because Sanyo did make a LA 3361 because most sanyo IC chips had LA I used to be a factory Warranty and service for Sanyo/Fisher .

Sincerely Richard

Yes, in fact when I was searching for the A3311, I came across LA3361. It looked quite different. I will send you the schematic of this chip from the Yamaha manual.

Is there a way to load an image?

And you are right. While chip says A3311 on it, elsewhere it does come up as LA3311:

https://icompplus.com/en/others/LA3311

Hi,

This is the schematic showing the chip (which I highlighted in yellow, as I found it confusing).

Is this chip made for a positive ground or is that how Sanyo has used it? 

If possible, I would like to change it to negative ground.

All the best

The quick answer is "not possible". The VCC to the circuit is negative voltage, the filter caps positives are connected to gnd and the transistors are NPN.

This is the same chip, used with negative ground. I suppose I could do enough surgery to change things from positive to negative but might be easier to build a new circuitboard. I wish I could find the original datasheet with a simple schematic.