Dual phono chip

[carlmart]

A friend of mine asked me for some help in improving a phono preamp on his receiver.

The problem is it uses a dual DIP chip: M5220P. It's supposed to be a low-noise chip, but it's all I know.

It's unlikely it's nothing special, so it might be interesting an upgrade to a better chip.

Being dual limits the choices somehow, so my personal favourite OPA627 unfortunately, is not an option here.

I wonder if it's good keeping the FET inputs or if the choices should be widened, including some bipolars. Once again, the bipolars I know, like the LT1028 or LT1115, are single types.

So what might be a good choice?


Carlos

[carlosfm]

For very low noise, OPA2228.
For a little higher noise but better sound, OPA2132.
You can also make an adapter and try the AD8620 (SMD).

[Russ White]

Try an OPA2227/2228, you may surprised how good it sounds. The AD8620 is also a good candidate, as well as the RC4560 which actaully sounds quite nice.

[tschrama]

NE5532 ... it isn't considderd hi-end, but the noise / thd spec are hi-end ...

[carlmart]

Well, with so many options to try, better put a socket first.

Can anyone tell me how you compute the gain of RIAA stage?

I say this because some chips may not be unity-gain stable, and I was just reading that at high frequencies the RIAA will eventually take gain to 1.

This layout uses a single chip, with the RIAA eq on the feedback.


Carlos

[Leolabs]

try 4580 too