Best preamp to go with Mcintosh 501s

I am currently using the C2300 and it sounds great, but I was wondering if anybody has experience pairing the 501s, which I think are wonderful, with other preamps that they find more satisfying than the C2300 or other Mac preamps. I was thinking particularly about the Conrad Johnson Act2, but other recommendations would be appreciated.
I have the MC402 amp and am using it with a Audio Research LS-26 pre amp and am very pleased with the results. I had an opportunity to try a Audio Research REF3 as an in home demo and was extremely pleased. Just waiting till I can afford to upgrade.
stick with the MC2300, symbiotic relationship
Save some money and buy a used C2200 and some telfunken tubes for it.
When I owned a pair of 501's I had them paired up with a ARC REF3 pre which I currently still use today, connection was via balanced IC's. Great combo!

I was at someones home a few years ago now and we were comparing gear, this person had MAC amps and was comparing the MAC 1000 pre, I brought over my ARC REF3 and we also compared, I preferred the MAC 1000 tube pre over all paired up with the MAC amps.

So it is really going to come down to a personal taste but at the same time be impacted with the rest of your components, speakers, cables etc.
C2200 can mary mc501s. Best match with less money than c2300