question on upgrading old board

[synap2012]

Hello, newby question for everyone. WHat would be an upgrade in quality from a " JRC 4558dy" op amp

I know very little about what I am looking for in compatibility between op-amps.

the reason I ask is I have a old Yamaha MR1642 that needs work, I want to try to upgrade a few things on it to help my DIY skills, before I tackle something that I would care if I destroyed.

anyone know where I can get schematics for such a board?

 

[Mooly]

The 4558 is like a dual 741 type OpAmp. You can do much better, but I would not go overboard on something like this. Fit TL072 OpAmps, and see what you think. Use solderbraid to remove the old ones.
Regards Karl

 

[synap2012]

Thanks ALOT!!!


can you upgrade transistors aswell? they have some "A970 BLo" Transistors in them.

also I have come to the understanding that the power supply has a lot to do with the performance of the components, how true is that and what would be a good power supply and power transformer to use to power the modules . How does powering multiple modules affect the power supply? I want to power 4 - 8 modules with one power supply.

I have seen these power supplies on Five fish studios called PSU-2448 how well would this work?

 

[jaycee]

Upgrading transistors isnt recommended as the specifics of the parts used will be relied upon. A970 will be 2SA970, which is a pretty good small signal transistor (you might find C2240 on there too).

Opamps - don't go overboard. Try either TL072 as suggested, or NE5532. Anything more pricey isn't warranted and might make the circuit unstable.

 

[Mooly]

How many are there in this thing ? Some Op Amps draw more current than others, the difference can add up if there are a lot.
4558 and TL072 draw little.
Regards Karl