Gemini PA-7000 op amp change

[Chunky70]

Hi all.
I have a Gemini PA-7000 pre amp which i would like to improve soundwise.
It has one JRC 4556 op-amp and four BA4558 op-amps.
What would be the best op amps to replace? I havn't opened it up yet but i'm assuming they are surface mount types.
Are LM4562's good to go or are there any others you would recommend?
I realise that this is highly reliant on the circuit design, perhaps the LM4562's are too fast in this circuit?
This is the preamp:
http://www.geminidj.com/pa-7000
Here's pictures of the insides (not very good quality, sorry)
http://techtalk.parts-express.com/showthread.php?t=208129

[Puffin]

Others may disagree, but I cannot see the point in doing anything to this. For what appears to be a Pro design there is a lot of fresh air in there. I would be surprised if a change of op-amps and caps is going to transform it.

Do you like the way if sounds?
What are you hoping to achieve?
Why did you buy this over a normal hifi pre-amp from one of the usual manufacturers?

I see you have two behringer power amps. A better pre would probably reap rewards.

[Chunky70]

Hi Rob.
I don't really use this preamp i actually use a modded TC-7510.
Acquired this in a house clearout and since it didn't cost me any money i thought i might tinker around with it to see what could be done.
It actually doesn't sound that bad but is perhaps a little tonally thin.
I'm only just sticking my toes into the modding waters and don't really know what's possible. I've been encouraged by the real improvments to my modded TC-7510 and thought i could start with the op amps. I can't see why it shoudn't have the possibilities off improvment. Perhaps the power supply could be changed as well?

[StanleyB]

You weren't kidding when you mentioned that the pictures were poor.. Are the 4556 and 4558 DIP8 or SIP8? i.e are there four legs each side of the package, or 8 legs in a straight line?
The 4556 is generally used for headphones.

If they are DIP8, then try AD826 for the 4556, and LM4562M for the 4558.
Or you can go a bit cheaper by using a LM4562 in place of the JRC4556, and the NE5532 in place of the BA4558.

I might have a couple of the 2nd set for you to try. But I would advice you to put the ICs in sockets so that you can play about with alternatives in the future.

Sound wise I expect you to get a bit more solid bass and better treble. I haven't got the cct diagram, else I could advice on any audio caps change as well.

[Chunky70]

Thanks for the info Stan. Had a look last night and they are SIP 8. If i fit sockets will these be DIP 8 or can i get sockets for both types?