McIntosh MC275 Versions
- Thread starter SoCal Sam
- Start date
I believe only the Mk 1 was point to point.
Mk 2 had a chrome chassis and a "commemorative" badge. Numbers were limited.
Mk 3 had a polished stainless steel chassis.
Mk 4 and 5 had higher voltage transformers
Mk 5 went to binding posts for easier hookup than the old style barrier strip.
Ron-C, how'd I do?
Mk 2 had a chrome chassis and a "commemorative" badge. Numbers were limited.
Mk 3 had a polished stainless steel chassis.
Mk 4 and 5 had higher voltage transformers
Mk 5 went to binding posts for easier hookup than the old style barrier strip.
Ron-C, how'd I do?
You are correct. Don't forget the gold finish on the Gordon Gow commemerative edition.
I don't remember where I got this, but it is from someone who contacted Frank Gow himself at Audioclassics, and I remembered that I thought it was important enough to archive in my file. It might even be from here? somewhere in the threads. I cannot take any credit for this, but it is very useful and an important letter of McIntosh history.
"As I have been going back and forth between purchasing an MC275 or MC2102, I've ask serveral folks who are knowledgeable about the various iterations. Here is a concise history I received from Frank Gow @ Audio Classics (son Gordon Gow of McIntosh fame), which I hope he does not mind my posting:
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
As a result of the patient and complete responses I've received from Frank, I purchased a new MC275MkVI from him, which should be here early next week."
Anyway, just trying as always to get it out there....D
"As I have been going back and forth between purchasing an MC275 or MC2102, I've ask serveral folks who are knowledgeable about the various iterations. Here is a concise history I received from Frank Gow @ Audio Classics (son Gordon Gow of McIntosh fame), which I hope he does not mind my posting:
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
As a result of the patient and complete responses I've received from Frank, I purchased a new MC275MkVI from him, which should be here early next week."
Anyway, just trying as always to get it out there....D
nsgarch
McStatic
Frank, it is the V that dropped the gain controls. The IV has them.
Also everyone seems to have overlooked that the V has a lead-free chassis (for EU compliance.) I personally prefer lead construction (for reliability) and so apparently do all the European Union military aircraft ;~) Lead-free board components are OK, I guess . . . . .
Also everyone seems to have overlooked that the V has a lead-free chassis (for EU compliance.) I personally prefer lead construction (for reliability) and so apparently do all the European Union military aircraft ;~) Lead-free board components are OK, I guess . . . . .
Good call. I had forgotten about the limited numbers of the "gold" edition.
I've owned several versions of the 275 and did own the MC2000 for years. What I would like to own is your 60th MC75's. Watch out.
SoCal Sam
Lunatic Member
Hmmm. It seems the IV is the one to get. It is leaded :-}, has gain controls, and the improved transformers.
Here's a nice collection of pics and info on McIntosh amps, including several MC275:
http://mcintoshlaboratory.tripod.com/instruments/poweramps.htm
http://mcintoshlaboratory.tripod.com/instruments/poweramps.htm
onedrop78
Active Member
The MKIV is cheaper to buy used as well! Gain controls aren't necessary if you have a preamp or are running balanced anyway. I think that the binding posts are a nice feature compared to the barrier strip. As far as lead solder is concerned....please post the scientific data regarding the reliability of leaded vs unleaded solder as I would be interested to know. Since I won't be flying in my amplifier or mounting guns to it, I am not overly concerned with that the EU military uses. But seriously, I would be interested to know.
drbryant
Member
This is a photo of the gold reissue from the link posted above, but it doesn't look like the model that I have. The power cord is plugged into the unit on the opposite end, and the fuse goes in on the opposite side as well. I wonder if this photo is a mock-up?
Attachments
Hi, my understanding is that leaded solder is still used by the military because it suppresses the formation of 'tin-whiskers' which can damage delicate solid state circuitry by shorting out components or pcb tracks.
This is an issue where reliability is essential and where the circuit energy is so low that that there is not enough energy to 'burn off' the whisker if it shorted out components - i.e. microelectronics.
If any 'tin-whiskers' formed in tube equipment it is likely they would simply be burnt off during the momentary short-circuit they caused due to the (generally) higher energies available -unless, of course, they formed somewhere (such as a grid circuit) where energies were very low.
This is an issue where reliability is essential and where the circuit energy is so low that that there is not enough energy to 'burn off' the whisker if it shorted out components - i.e. microelectronics.
If any 'tin-whiskers' formed in tube equipment it is likely they would simply be burnt off during the momentary short-circuit they caused due to the (generally) higher energies available -unless, of course, they formed somewhere (such as a grid circuit) where energies were very low.
ron-c
Addicted Member
ROHs or removal of hazardous substances has no negative impact on performance if properly engineered. There is more to this than lead as a whole list of hazardous substances are removed. I for one would not support the continued use of materials that will someday result in the contamination of ground water and other ills.
All current McIntosh models are of course ROHs compliant.
Thanks,
Ron-C
All current McIntosh models are of course ROHs compliant.
Thanks,
Ron-C
william13
That's not me
mc275 IV vs VI
Does the IV version have the same improved transformers as the "VI" version? Is the bass performance better on the IV than the V and equal to the VI?
Does the IV version have the same improved transformers as the "VI" version? Is the bass performance better on the IV than the V and equal to the VI?
Haven't the 50th Anniversary and MkVI also eliminated the tertiary feedback winding from the output transformer, taking the feedback direct from the speaker winding ?
If so, this is an interesting development as the MkIV and V applied 'balanced' feedback to the two halves of the driving circuit from the tertiary feedback winding.
Would be interesting to see how this is accomplished on the new models - imagine the circuit has changed somewhat (unless the secondary is centre tapped and the tap connected to chassis perhaps, but haven't seen a schematic).
Anyone have any ideas ?
If so, this is an interesting development as the MkIV and V applied 'balanced' feedback to the two halves of the driving circuit from the tertiary feedback winding.
Would be interesting to see how this is accomplished on the new models - imagine the circuit has changed somewhat (unless the secondary is centre tapped and the tap connected to chassis perhaps, but haven't seen a schematic).
Anyone have any ideas ?
ron-c
Addicted Member
The new model takes the feedback from the speaker side of the output autoformer where in all other versions the feedback is from the amp side of the output transformer. The increased bandwidth of the output transformer has allowed this change.
Sound-wise this translates into better, tauter, deeper bass.
Thanks,
Ron-C
Sound-wise this translates into better, tauter, deeper bass.
Thanks,
Ron-C
