2100

[Matt Mincer]

Hey Gangstas

I picked up a vintage 2100 this weekend. The plan is to refurb it. Are there any musts or don'ts I should be aware of?

Thanks
Matt

 

[Mike Gibson]

I would start by reading the hints & kinks sticky in this forum. Also some of the other stickies will help in finding sites with more information.Lots of vital info there. Welcome to the world of McIntosh.

 

[Matt Mincer]

Will do!

 

[miketuason]

Matt, 2100 are great amp, I had a pair that I've used for 20 years and loved it until I upgraded to the newer Mcintosh amp. If you live Sothern CA, I highly recommend George Myer for repair. They are Mac specialist and they have repaired mine in the past and very happy with their work.

 

[techguy0192]

If you have the knowledge/skill go for it. Otherwise, it would not be a bad idea to let a seasoned tech go over the unit. These are fantastic amps are hard to beat in top working order.

 

[geespot]

lots of factory updates to these, check with the factory of an authorized service center

 

[Matt Mincer]

Well, I spent a good 3 hours trying to figure out why the left preamp wasn't working. It couldn't be a simpler circuit but it was throwing me for a loop. I guess it was a cold solder joint because taking out and testing the transistors fixed the problem. It seems to be working but I haven't been able to really crank it. Small basement and small speakers.

The schematic I downloaded from HiFi engine show a power switch but this one doesn't have one. Odd.

I sent an email to the Mac service department about the upgrades. I'm in electronics for a living so I'm going to try and do the work myself.

Thanks for everyone's input.

Matt

 

[nj pheonix]

Common wisdom is to update driver boards.
As i understand it, these were the same for the 22 and 2300s , which chewed them up pretty good.
When I was working on mine , I exchanged messages with Terry D.
He said if the old driver boards aren't burnt up they're fine.
There are a pair of old rca transistors with built in heat sinks that are no longer available.
Mac makes an upgrade kit and you can order new driver boards from mac.
(I opted to keep mine stock because it had no issues.
I did replace the elytics on the driver and the amp modules.
I have some notes (from after mine) that Terry gave in another 2100 thread.
If I don't post later it means I forgot, message me.

 

[John James]

...... If I don't post later it means I forgot, message me.

I know the feeling!

 

[Matt Mincer]

This was from service at Mac. Nice folks.

"
There are no “upgrades” but if you find you need to replace the transistors Q11, 12, 13, and 14 with our replaced parts you need to make the following circuit change:
A. Remove C13 and C14
B. Remove R17 and R18 (22Ω, ½ W) and replace them with 18Ω, ½W (141206)
C. Remove C9, C15, C10, and C16 (0.0012mfd, 10%) and replace them with a 680pF disc cap. (061034)
132038 is replaced by 132153 (2N5681)
132039 is replaced by 132154 (2N5679)
There are no service bulletins but there are plenty of notes regarding the many changes during production of this model in the service manuals I included. This should be everything you need to repair the amplifier."

 

[c_dk]

Mac went through 3 sets of drivers for this series of amps....most of them were built with the 2nd set after the 1 set were driving pro users like the Dead crazy with blowing whole output sections of their MC2300s.

I believe the issue was part of the ongoing issues with early PNP devices and thermal runaway.

The last few hundreds of units were built with the MC2300 updated RCA drivers with round heatsinks instead of the squarish ones with the transistor permanently attached.

First thing to do is pull the driver cards and clean the edge connectors with a pencil eraser and the sockets with D5.

Give it a stressful bench test at low impedance loads and frequency extremes.

You need to get it hot into a load box and watch for the distortion to stabilize....

 

[arts]

Mac went through 3 sets of drivers for this series of amps....most of them were built with the 2nd set after the 1 set were driving pro users like the Dead crazy with blowing whole output sections of their MC2300s.

I believe the issue was part of the ongoing issues with early PNP devices and thermal runaway.

The last few hundreds of units were built with the MC2300 updated RCA drivers with round heatsinks instead of the squarish ones with the transistor permanently attached.

First thing to do is pull the driver cards and clean the edge connectors with a pencil eraser and the sockets with D5.

Give it a stressful bench test at low impedance loads and frequency extremes.

You need to get it hot into a load box and watch for the distortion to stabilize....

Are the 2N5679 & 2N5681 the final and/or best choice for drivers? I'm just curious as I am still using the 2N5320 & 2N5322.