Scythe Kama Bay SD-1100 input section opamp replacement or bypassing?

[rickedd46]

Hello fellows,

I have a Scythe Kama Bay SD-1100 amplifier with a yamaha YDA138 chip which has a pair of LM324 opamps right before the inputs. I tried to get a schematic from the manufacturer but I forgot to follow up with the calls.

This is the YDA138 schematic.

http://www.yamaha.co.jp/english/prod.../4DA138A20.pdf

As you can see Scythe went a little bit further and added a lot of stuff that obviously isn't on the original schematic.

This amplifier plays pretty well when compared to the ta2024 based amps I have but I don't think i am listing to the yamaha chip in its pure form so it is an unfair comparison since the SDA-1100 does not have a direct signal to the YDA130. I've read enough bad feedback from people who have listened to the LM324 and was wondering if there's any decent replacement for it if not then if I could bypass them. The LM324 is a single supply quad.

Here's the schematics...

http://www.national.com/ds/LM/LM124.pdf

Here are some pics of the amplifier and one next to Arjen's ta2024 board.

Thanks.

Ricardo.