What is a great preamp match with the Mcintosh MC754 amplifier?

Hello all,
I just recently picked up a pair of Mcintosh MC754 amps. I am running it with an older Adcom preamp, but would like to upgrade to a much better preamp. I'm thinking of getting an Adcom 715 or 815 preamp, but I am open to other suggestions. My budget is around $500 used and I don't mind buying an older preamp that sounds great. It does not need to have a phono section in it. If anyone has experience with the MC754 amp I would love your advice.
Just in general,  I would want to mate a Mac amp with a Mac pre-amp.  Don't know enough about that model to say exactly which one, but I'm sure there are pre-amps by Mac designed specifically to work with that amp hopefully with the features you want.   Features are a big part of selecting a pre-amp.
Mac + Mac, the way I’d go.

Not a lot of those made, 15-1600 something like that.

No Macs for 500.00, maybe a logo... ;-)

If you can find a Parasound Zpre3. I have one they sound quite good with my MC275 CE. I have older Mac Valve units, MC225,240,275 all sound quit good, with the parasound, and planar based speakers.

It has remote, sub out, all kinds of onboard goodies..
Check one out.. I got mine for 295.00 it was a bargain from what I was told. After I got it, I knew it was.
Great unit.. I'd pay 500.00 no problem at all.

I'd recommend the Mac C712 or C15 pre's for your amp, both  are good, and have remote control. However, you will have to cough up a bit more coin for them on the used market.