New McIntosh MC2105 owner with questions

[DavidinNC]

Hello all,

I recently acquired an MC-2105. The faceplate is cracked, another is on order and should be here this week. I’m trying to date the manufacture, and the serial number is partly obscured. All I have is 2YM6. Is there any other way to tell the manufacture date at all?

Also, most of the images I see have different control knobs. Did McIntosh change these at some point during the lifecycle of production?

 

[BamaBilly]

I can’t help with the serial number but I do know it’s pretty common for folks to change the knobs so they match other pieces of Mac gear in their system. Those are the same knobs that on my 2205 so I think they’re correct.

 

[clinic-audio]

Hello

dating the manufacture is not usefull
it does exist more than 12 service manual for MC2105 with all different types included and it is difficult to give an exact answer but it does exist a serial chassis number which is easy to see from the outside and one double (copy) number is under the power transformer . This is true for all units . A long time ago I remember that if you bought one unit with serial number erased you can call the factory and give this chassis number and somebody gave you the right serial number and then the date of manufacture . Today it is over because this "list" disappear with the time . This was the best way to rescover what you were looking for .
But today there is something possible to do :
If this unit has never been repaired you can take a look on the manufacture date code on power transistors and you will have a more accurate answer than the one you have today .
If your amplifier has been repaired the right answer is canceled
You can also read the compandor of Larry and also read information on the Roger Russel web site

That's all that I can do for you today

Here is a picture of one chassis number I was talking about ( MC275CE 10301 chassis number as example )

 

[DavidinNC]

Hello

dating the manufacture is not usefull
it does exist more than 12 service manual for MC2105 with all different types included and it is difficult to give an exact answer but it does exist a serial chassis number which is easy to see from the outside and one double (copy) number is under the power transformer . This is true for all units . A long time ago I remember that if you bought one unit with serial number erased you can call the factory and give this chassis number and somebody gave you the right serial number and then the date of manufacture . Today it is over because this "list" disappear with the time . This was the best way to rescover what you were looking for .
But today there is something possible to do :
If this unit has never been repaired you can take a look on the manufacture date code on power transistors and you will have a more accurate answer than the one you have today .
If your amplifier has been repaired the right answer is canceled
You can also read the compandor of Larry and also read information on the Roger Russel web site

That's all that I can do for you today

Here is a picture of one chassis number I was taking about ( MC275CE 10301 chassis number as example )

View attachment 2622691

Thank you for this information, I will make not of these when the refurbishment starts.

 

[Refugee]

My unit has the earlier knobs (all bare aluminum with no black center). I think they were also produced with the later knobs you have in later years of the model's run. As "BamaBilly" said, many people change the knobs to match other units so you can't really use the knob type to date the unit. If you send McIntosh the number 2YM6 they can give you a range of time that the unit was produced but they do not have specific info. They told me 1970-71 for mine. They were made between 1967 to 1977. There are many versions of the service manual. Make sure you get the right one if you do any electronic repair/restore work. The glass goes on pretty easily. Frame the new glass on all four sides and then mount the framed faceplate. You may find some foam that has degraded on the light diffuser and around the meters. I replaced with pieces of felt to avoid rotting foam in the future. might want to replace the bulbs while you have the faceplate off.
Great Amp...Enjoy!

 

[DavidinNC]

My unit has the earlier knobs (all bare aluminum with no black center). I think they were also produced with the later knobs you have in later years of the model's run. As "BamaBilly" said, many people change the knobs to match other units so you can't really use the knob type to date the unit. If you send McIntosh the number 2YM6 they can give you a range of time that the unit was produced but they do not have specific info. They told me 1970-71 for mine. They were made between 1967 to 1977. There are many versions of the service manual. Make sure you get the right one if you do any electronic repair/restore work. The glass goes on pretty easily. Frame the new glass on all four sides and then mount the framed faceplate. You may find some foam that has degraded on the light diffuser and around the meters. I replaced with pieces of felt to avoid rotting foam in the future. might want to replace the bulbs while you have the faceplate off.
Great Amp...Enjoy!

Thanks much for this guidance, will certainly look into all the recommendations. I like the felt idea especially.

 

[Refugee]

Here is a picture of felt around the meters. It was folded once and stayed in place without any adhesive.

 

[markd51]

Not sure about knobs? Mine were '74 models and had the earlier knobs. I'm pretty certain they never did come with those later knobs, that another owner swapped them out.

 

[VintageMac]

The black-center knobs were first introduced with the MR78 in 1972. Your MC2105 came with the earlier knobs. Someone changed them out.

But, if you like them, then they are certainly "correct"!

Larry

 

[DavidinNC]

Thanks for everyone’s input so far, I will keep the knobs I have now. I don’t see a reason to spend what those cost simply for having the “correct” ones.

 

[damacman]

I would. The ones you have are desirable and therefore next to impossible to find anymore ...

 

[twiiii]

For a long time Mcintosh would stamp the serial number on the inside of chassis of the pieces they built in addition to the external serial number.

 

[nooboy]

Not sure about knobs? Mine were '74 models and had the earlier knobs. I'm pretty certain they never did come with those later knobs, that another owner swapped them out.

Sadly.

 

[edwinh]

Here is a picture of felt around the meters. It was folded once and stayed in place without any adhesive.

Wow, that looks so much cleaner than either of my MC2105s. Of course, they were abused in the musical instrument and pro audio world.

Good luck getting all back together perfectly! You have an awesome amp.

And I like the knobs that are on there.

 

[DavidinNC]

Well, she is going to the shop along with my C32. Want them both in good shape when I hook them up. Received a replacement faceplate and excited to see it. Operation in a few weeks!