which opamp is better?

[pho_boi]

hey everyone,

i just purchased an old MD player to muck around with, and when dis-assembly it i found out that it uses a JRC op amp model number NJM2904, i looked up its spec sheet and looked up another opamp from other companies that would match the pinouts and such. after searching for a bit i found an opamp from MAXIM in its Audio section. both run from a single voltage supply and all the pin outs are exact. But i don't know which would be the better? maybe someone could give a look at both specs and recommend me if i should go and swap the opamp out. the player runs on 2 AA batteries and both amps can use the 3V fine. but how do i tell which one has the better sound?

here are the PDFs:

NJM2904

MAXIM

 

[tangent]

The 2904 is a standard dual op-amp. If that's indeed what's in your player, you could replace it with any number of common chips.

The Maxim chip you posted is a completely nonstandard op-amp. You must have used a bad link or something, since you say these two are supposed to have the same pinout. They're not even close.

 

[pho_boi]

no that is the right opamp, the package that i was looking at was the 4167. it is 8pin SO package and it is shown at near the end of the PDF sheet.

 

[tangent]

Ah, I see.

Well, a quick scan of the datasheet says the Maxim will be better. 2V/us slew rate for the Maxim vs 0.5 for the NJR, and 5MHz unity-gain bandwidth vs. 0.2 (!) MHz for the NJR. Also, the Maxim chip is rated down to 25 ohm loads, whereas the NJR chip is only rated down to 2K, and at that level it has a lower output voltage swing than the Maxim at 25 ohms.

None of that means it will sound better. It just means it ought to. You won't know until you try it.

If I were you, I'd get a selection of similar chips, in case you find you don't like the Maxim, or find that it misbehaves in that circuit. I would think that almost any modern 3V RRIO chip would sound better than that bletcherous NJR thing.