Difference between McIntosh MR65 and MR65B


Does anyone know how to tell between the McIntosh MR65 and MR65b receivers. I know the 65 is mono and the 65b is stereo. Mine has MR65 on the rear panel but is (and says) stereo on the front.
I am assuming it is a 65b then..?..??

Also, was this the first McIntosh stereo receiver?

Thanks for any help!!
ron8668
Looks like you can tell by the tube compliments. See here:

http://www.roger-russell.com/tuners.htm

Arthur
What arthur says plus: All the 65's say 'Stereophonic' front, and 'stereo' back. They were basically mono but had an output for an external multiplex adaptor. There was also an optional muiltiplex section available for them which you could order with the unit, or have installed later.

The 65B's all carry the "B" designation and are stereo units.
Thanks Author and Nsgarch!

I just inherited all this tube equipment. Aside from the McIntosh I have:
Cary Audio CAD301 amp,
Cary Audio CD 300 cd player,
Joule Electra LA100 preamp,
Moscode Minuet preamp,
Tice MBF-3 AC conditioner,
as well as some sweet Tice 416 speaker cables and interconnects.
I am trying to figure out 1) what the heck I have 2) if I really want to get into this tube audio stuff or just sell it and buy me some new Revels!

Thanks again for your help!!