Here is a letter that I saved and got somewhere (probably here) from the late great Frank Gow on the Mc275 and its reissues. Maybe it will be of some use to you. I find it interesting, that is why I kept it:
"The Commerative version is an updated adaptation of the original MC275 with balanced inputs as well as single ended inputs, PC board design vs. point-to-point wiring used in the original mc275 and built on a chrome plated chassis. These were limited production which caused considerable annoyance with customers who were not aware of the limited offering.
Subsequently, the factory introduced the MC275-SS Stainless Steel chassis version of the MC275-II without the Gordon Gow commerative badge. This was offered for a few years to pacify customers who missed out on the limited production Gordon Gow Commerative Edition. This was the same product design as the Commerative Edition MC275. They also made a very, very limited production in gold for approximately 200 units, of which most went to Japan.
As a result of the better than anticipated success of the tube product, McIntosh decided to make the 50th Anniversary MC2000 130 wpc dual mono designed by Sidney Corderman, one of the founders and long-time VP of Engineering @ McIntosh. This also was a limited production design with less than 800 units made. This was priced @ $15k and not everybody was able to purchase such a high priced tribute to McIntosh history. This was followed by the MC2102, a cost reduced version of the MC2000 using a common mode power supply @ 130 wpc which found incredible success.
At this point, McIntosh realized there was a need to commit to tube designs as the demand was continuing to grow by significant amounts. We had also pressured them to make a companion preamp better than the C22-II Frank McIntosh Commerative, an updated version of the original C22. This was offered during the time of the MC275-SS. Finally they introduced the C2200 current model preamp with meters, remote control, etc. to far exceed the performance of the C22 & C22-II Commerative models.
Demand still persisted for the MC275 to be available which lead to a redesign of the MC275-II & -SS versions. The current MC275-MK-IV, V or MK-V as now referred to, offered a major improvement with a 490 v power supply vs. 450 in the Commerative and Stainless editions. McIntosh also added more laminations in the output transformers which increased the bass performance over the original designs. All shiny chassis units are now highly polished stainless steel which eliminates the cracking and corrosion problems associated with chrome. The power supply improvements contributed to better dynamic expression and a more robust bass character. So far, this has proved to be the best sounding and compares very favorably against the MC2000 & MC2102 despite their having higher power.
Today, the best results seem to be provided by using the C2200 preamp and MC275-MK-IV, V or VI. The MK-IV came with gold small spade screw terminals, no gain control with balanced and single ended connections and power on/off switch. The MK-V changed the speaker terminals to 5-way plastic binding posts. The MK-VI changed the plastic binding posts to gold metal WBT style connectors. Circuits for all these are the same. McIntosh still lists this as the MC275 and makes no model distinction regarding the production changes implemented with the speaker terminals.
I realize this was lengthy but thought it might be helpful to have the evolution as well as technical changes and benefits associated with them. Let me know if you have more questions or need additional information. Thank you for the opportunity to be of service."
Best wishes,
Frank Gow - Sr. Sales Consultant
Well, there you go...
