Audio Research REF 75 vs VAC Phi 200

Anyone compared these two highly rated power amps? Both companies are well regarded in the audio community. These amps sell at approximately the same price point. The VAC may have a little more power.
I recently read a thread where people were having issues with their ARC amps, and it was mentioned that some preamps do not play well with ARC amps and could cause problems with them. I have no idea about the details of this or if it's correct, but I'd at least look into this and see if your preamp is a good match if you ultimately decide on an ARC amp. I'm sure others know a lot more about this, but just wanted to bring it up just in case it's a legitimate issue. Best of luck.
Good point by Soix.

Here is the thread that he appears to be referring to. Apparently the manuals for some ARC amps indicate that if non-ARC preamps are used with them damage may occur. The link opens at a post in which I speculated about possible explanations.

Whatever the reason may be for their statement, my suspicion is that it would be unlikely to be an issue with most non-ARC preamps, but I suppose it conceivably could be an issue with some.

Best regards,
-- Al
I have a REF 75 and there's nothing in the manual warning about using the amp with non-ARC preamps.

I don't drive it with a ARC preamp.

The REF 75 only has balanced inputs, so you do need a preamp with real balanced outputs.
I haven't heard the VAC amps in my system, but I own the
REF 75. Don't judge the REF 75 until you change out the
tubes for KT 150's - available from Upscale Audio. While
the REF 75 is amazing with the stock KT 120's, it is in a
different league with the KT 150's. If you go with the KT
150's, you'll have to leave the top cover off of the amp
because the new tubes are a bit too high. Sounds better
with the cover off anyway, so ... so what?

My current system:
ARC REF-3 pre amp
ARC REF-75 amp
ARC PH-8 phono
ARC CD-7se
Well Tempered TT. Original issue and highly modified.
AT-0C9 MK III cartridge.
Speakers: Legacy Signature IIIs biwired with Cardas
binding posts.
Oregonpapa ... what is the ARC CD-7se? Are you referring to the CD-7 with the upgraded power supply: (1) 5881 tube and (1) 6H30 tube??

Glad to read that the KT-150s are working out. Still scratching my head about why ARC continues to hold back officially blessing the KT-150 for use in its current amp lineup.

Yeeesss .... I've read the hearsay reports that so and so at ARC said the KT-150 are ok. I want to see it come in writing from ARC. They've had that tube in life testing for two or three lifetimes already. I doubt this type of conduct would have happened under Mr. Johnson's watch.