McIntosh c1100 vs audio research ref 6se vs Ayer KX-R

Johnto
Using a mc255 5 channel amp, chord Hugo tt2, roon nucleus, b&w 804 d3, and a b&w center and sub.   And looking for a very nice stereo preamp with stereo bypass.  Also use a marantz 5014 avr which is fine for ht.

thanks

Of course your going to buy the McIntosh! One button to turn everything on using power control, plus the amazing lights, not to mention im sure the C1100 sounds pretty pretty pretty good :-) O did I mention they have been in Binghampton NY since the Earth's been spinning....lol...NO really they have I think. Excellent Customer Service...CHECK! Best resale value....CHECK! Honestly I buy MAC because I dont like it when things are not working, with McIntosh I never worry about this ever. Ive never had to send my amp in for service in over 13 years now.

Matt M

I’d do the Mac for sure. The ARC preamps don’t always work well with Mac amps as the output impedance of the preamp is a bit high for the relatively low input impedance of most Mac amps. You can always try it and see. 
George 

Why is low impedance of a Mac going into an arc preamp with a high impedance a bad thing?

It has to do with the ability of the preamp to properly drive the power amp. What you want is low impedance on the output of the preamp and high impedance of the power amp. There are tons of articles written by folks way smarter than me so google can be your friend here. From personal experience the ARC preamps have a bit higher output impedance as is often the case for tube preamps of around 200 ohms. If you look at measurement from some of the reviews however at the higher frequencies they can go up to 2000 ohms almost. That said with the McIntosh amps around 22k ohms that can lead to a loss of some of the detail.  With amps that have input impedances of 100k ohm or more that isn’t a problem any longer. That said ... it will work and some folks like the sound but I wasn’t a fan when I tried it for sure.