I sent an email to McIntosh Laboratories and got this reply.
-----Original Message-----
From: Hinton, Chuck <CHinton@mcintoshlabs.com>
Cc: Cornelius, Ron <RCornelius@mcintoshlabs.com>
Sent: Tue, Oct 6, 2015 3:11 pm
Subject: RE: Contact Us Enquiry at McIntosh Laboratory, Inc.
Hi xxxxx,
No, we have no schematics for those.
All McIntosh tube amps ever made had the unity coupled circuit.
Chuck Hinton
McIntosh, Wadia and Snell Tech Support
McIntosh Sales Admin
Toll Free: (888)-979-3737 X311
Binghamton New York - "The Original Silicon Valley"