McIntosh - Hints and Kinks

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Most units we are collecting and using daily are up to 50 years old and still sound as good and look better than ones by other manufacturers that are 10 to 20 years old. Simply put they are worth putting time and money in to keep operational and working to specifications that most newer brands can only wish for.
 
Please educate my ignorance. With all these problems with McIntosh equipment why is it so a) popular and b) expensive?

You realize we're discussing a lot of equipment that is easily 30-40 years old, right? :yes:

The longevity and performance of these products are the reason why they're popular, and with popularity comes cost. :music:
 
Please educate my ignorance. With all these problems with McIntosh equipment why is it so a) popular and b) expensive?

Just to give you some examples of recently discussed models:

MC60: Weight 46 lb. Sold from 1955-1961. Last retail price $219.00
MC240: Weight 56 lb. Sold from 1960-1969. Last retail price $288.00
MCD7008: Weight 24.5 lb. Sold from 1992-1996. Last retail price $2200.00
MR73: Weight 24 lb. Sold from 1969-1971. Last retail price $549.00
MA5100: Weight 25 lbs. Sold from 1966-1972. Last retail price $449.00

All of the above can usually be easily fixed by replacing dried up electrolytic caps, replacing the occasional out-of-spec resistor and fitting a new NTC thermistor. The build quality of these units is outstanding, as are measured and percepted performance.
And if you some research and adjust for inflation, you'll usually see that the used prices are above or equal to the original retail price, which makes them a reasonable investment.
 
Please educate my ignorance. With all these problems with McIntosh equipment why is it so a) popular and b) expensive?
Have you checked out any late-50s, 60s & early 70s U.S. made automobile prices recently? Pretty much the same with them with one notable exception. Most old McIntosh, once serviced, will/can be used daily for the next 40-50 years without additional service. Essentially has an infinite lifetime. Very few similar era automobiles see daily service.
 
Just a question about the 240...
When a power tube goes, what fuse does it take with it or does it even take a fuse out?
 
RE: Ground Problem resolved: MA5100 - bass Control

Terry thanks for the help - I soaked it a lot for weeks and it finally cleared up almost 99%. I did call Mcintosh and they said they have the POT for the bass control at $5 Flat type not knurrled...I think it's fine now.

Thanks again.

John
 
C24

Apologies if this has likely been covered previously.
I may be tasked with renovating an older gent's shelf of Mac consisting of a C-24, MC-240, and a pair of MC-75. Having heard the sys I think it prudent to start with the pre and expect to clean switches, pots, transistor sockets, and replace all the axial e'lytics with a modern equiv, and probably the PS e'lytics. The power amps will be next as I'd like to keep his pride-and-joy playing for him thru most of the process. He also has a couple tube era Mac tuners presently unused out of service.
What are the 'got-chas' on doing all this for the C-24 and what replacement signal and other caps are advised/recommended ?
TIA!
 
Can't change too many caps in the old gear. You are definitely on the right track. These guys http://www.tubesandmore.com/products/capacitors have the multi-cap cans for the amps. You might also want to replace any selenium devices with silicon.
Did the C24 (no dashes in McIntosh model nomenclature) use transistor sockets? Never seen one in the flesh.
For the small lytics most folks go with Nichicon's Muse audio series (KZ, etc.). Sold several places, but Mouser and DigiKey never seem to have everything I want so I usually purchase here http://www.hndme.com/productcart/pc/viewcategories.asp?idCategory=73 as he seems to stock most everything.
When you get to the tubes, the caps will depend on how much money the owner wants to spend. Caps can get expensive very quickly in the higher voltages for tubes. The less expensive Mundorf are pretty nice for the money. Have also read good things about Amp Ohm caps.
 
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Thnx for response, Now have a service manual to study. This is a transistor unit with socketed devices, easily replaceable and probably in need of contact dope and work-in. Pic from another forum;
C24_inside.jpg

The critical audio e'lytics appear to be but four all in the line driver stage, all of the rest on the skiz appear to be reliable film types. The PS e'lytiics may or may not be in need of replacement and as always I need to check for any eyelet-to-chassis grounding interface problems. I know the subject unit has a residual hum problem and noisy volume pot that may or may not remediate with Faderlube. The power switch is also predictably defective thanks to the then-standard U.S. practice of not having a snubber cap across them, thus guaranteeing eventual failure.
Any other suggestions welcome, TIA!


Can't change too many caps in the old gear. You are definitely on the right track. These guys http://www.tubesandmore.com/products/capacitors have the multi-cap cans for the amps. You might also want to replace any selenium devices with silicon.
Did the C24 (no dashes in McIntosh model nomenclature) use transistor sockets? Never seen one in the flesh.
For the small lytics most folks go with Nichicon's Muse audio series (KZ, etc.). Sold several places, but Mouser and DigiKey never seem to have everything I want so I usually purchase here http://www.hndme.com/productcart/pc/viewcategories.asp?idCategory=73 as he seems to stock most everything.
When you get to the tubes, the caps will depend on how much money the owner wants to spend. Caps can get expensive very quickly in the higher voltages for tubes. The less expensive Mundorf are pretty nice for the money. Have also read good things about Amp Ohm caps.
 
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Very simple compared to the C28 and later preamps. One of the issues with later preamps is grounding. The grounding lugs get some corrosion around them which results in a poor ground. Not sure if the C24 using the same grounding scheme, but something to look at if it does.
 
Thnx again!

I see you have a pair of MC50, I have a single as a doorstop at present from a county ballfield announcers booth. It's my only piece of Mac ever and I don't have a place/use for it, yet, I just like seeing it around I guess as they were soooo droolworthy when I was a lad.
 
Very simple compared to the C28 and later preamps. One of the issues with later preamps is grounding. The grounding lugs get some corrosion around them which results in a poor ground. Not sure if the C24 using the same grounding scheme, but something to look at if it does.

I see basically 2 versions of this preamp, the 'later' has additional e'lytics on the phono/tone board. Is it recommended that these be 'updated' when recapping and if so, are additional changes recommended or is it best to leave it as-is with a basic re-cap of the Bakelite tube & other axial e'lytics?
 
Mac output transistors

I have noticed that the 132-070 op transistor used on some MAC models is recommended to be substituted by an MJ15003. I was reading a MAC forum thread on Yahoo where a service center rep said the original part is a 2n5303 (which is still available ).Is the MJ15003 an upgrade?
Specs show the 2n5303 as a 20amp 80volt transistor.Does anyone know about this or have any comments?
 
If you order a 132-070 from the factory you will get a MJ15003, a common, inexpensive, and reliable part that is still in production by several manufacturers.
 
Hi Terry,

I have an all original C11 that I bought two months ago. Today started doing a noise (not continuosly, aleatory) on right channel, when function after 20-30 minutes. The noise is short, low frecuency, something similar when carbon potentiometer have problems (sorry my description!)..
Can you give me some orientation to start analazing the problem?.

Many thanks.
 
Could be a dirty tube socket, clean pins with DeOxit D5, to a bad filter capacitor, replace can or temporary bridge the bad section. With these hints and not knowing your technical level I think it may be time to go to the shop.
 
+1 what Terry sed, these things are so full of contaminated contact interfaces that need reconditioning and suspect age-deteriorated components that a meticulous step-by-step renovation procedure is mandatory to restore reliable top performance.
 
Many thanks for your help.
Was a bad cap of 0.01uF on right output stage, bumblebee that I replaced for a black beauty. Taking oportunity I replace the two in same step.

Thanks again
 
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