@#$%!*&#%$^....!

[BlindedByScience]

....so, I have two pieces of 30 year old McIntosh audio gear that I dearly love. After 30 years, it was time to re-lamp them and replace the volume pot in the preamp, and the two gain pots on the power amp. Long as I'm in there, it seemed like a good time to pull inter-board connectors and clean their contacts, all other pots, switches, etc.

These units are hella stout and built like a tank, but it quickly became clear that they really didn't spend much time thinking about being able to take them apart for service. Perhaps they thought that you'd never need to take them apart, but I digress.

The preamp went well, though it took three times as long as I figured it would. A thousand screws, much fragile soldering, and it was back together. Then, it was time for the power amp.

I figured out I'd been shorted one of the teeny "grain of wheat" solder in lamps for the front panel, so I decided not to replace them; the new ones are slightly brighter due to age and I didn't want one "dim bulb" as I figure there's enough of those around here anyway..... I figured that would save me some time. Turns out getting to the gain pots on the front panel was a s#!tload harder than I thought. However, after a couple of hours, and without becoming intimate with the hot soldering iron, I got things swapped out and back together and all was looking very well. A million screws go back in, the fragile glass front panel back on without cracking (a win there, to be sure), and all was looking well. Until I tried to put the knobs back on the new pots.

Crap. Damn. The knobs, with a spring loaded flat in them, just would NOT go on the new pots. Out came the Starrett and son of a bitch, the control shaft diameter is the same, but the flat on the new pots are almost exactly 0.030" thicker than the flats on the old ones. Now, thirty thou may not sound like a lot, but it's plenty to prevent the knobs from going back on. Who would have thought? Not me, to be sure.

Well, I guess we'll be watching with TV speakers tonight and the nice folks in the parts department at McIntosh will be getting a phone call bright and early on Tueseday AM...... :angry: Time for a nice smoke and a high octane beverage.

Hope your afternoon went lots better than mine did; Here's to the weekend, gents - B.B.S.

 

[NorCalCigarLover]

I hate when that happens ...... :laugh: .

Have a great weekend Tom

 

[Ginseng]

You've got the patience of a saint to have gotten that far. I probably would have hit them with a hand sledge and then gone out to buy a Mark Levinson or Krell set.

Wilkey

 

[AVB]

I remember the MC-240 I had, I could heat the room with that little 40wpc amp. I always thought a rack of MC-600's would be cool if I hit the lotto.

 

[MadMonk]

Only Glow in the Dark Amps make real Music. Glass Audio!!!!
Damn I'm a recovering Audiophile!!! I do not need temptation!

Those Macs are built like tanks! I love them.

But, no teasing, you have to tell me what else you have in your System.

I Sold my Pre-amp and Amp a while back, Counterpoint Pre, Cary Amp.
Still have Thiel Speakers. Sony SACD player. Will probably go with a Conrad Johnson, or a Cary Integrated some day.
Don't have the Room, and have a 4 yr old that would love to get his mits on my aluminum tweeters.

 

[NullSmurf]

If you had fixed mine instead, it would have taken you 20 minutes.

 

[BlindedByScience]

.....But, no teasing, you have to tell me what else you have in your System.....

After years of building high end recording studios and owning high end audio, I really scaled back. Very modest, very small stuff anymore; The McIntosh components are the C504 pre-amp and the MC-502 power amp. The McIntosh components are very special to me as I "won" them with spiffs by selling McIntosh components back in the 70's / early 80's. I still have the shipping containers for them, and the "ship to" address is my old home address, with my name on it. Cool.... A single pair of Boston Acoustic floor standing three way column speakers, a Toshiba HD-DVD / CD player, a Yamaha tuner, and a very nice but rarely used Nakamichi cassette deck complete the line up. While modest by any measure, the system sounds wonderful, even though it's a two speaker set up. I get "what....no subwoofer?" from folks from time to time, then they hear what properly placed speakers with McIntosh power behind them sound like..... It sounds way bigger than it looks....which keeps Ms. B.B.S. happy.

I have the small Boston Acoustic 2-way speakers that match my fronts, and maybe someday I'll lose it; get rid off the McIntosh stuff and get a nice Denon AV receiver. Maybe.....someday..... :laugh:

Cheers - B.B.S.

If you had fixed mine instead, it would have taken you 20 minutes.

....Bruce, climbing to the 30th floor, throwing the unit off the top, and yelling "Fixed..!!" doesn't count..... :laugh:

 

[MadMonk]

Wow, sounds like you had a lot of fun in your vocation. That is great. Too bad a lot of folks don't understand speaker placement. Of course Tubes help with the huge soundstage. But if more folks understood how
speaker placement totally has effects on the bass, tone, imaging, etc. So I totally agree that a decent speaker doesnt require a subwoofer. I was perfectly content without a subwoofer. I'll take taught and tuneful bass over thump anyday. Besides, my theils are so fast, for a long time, no subwoofer would have worked. I also typically don't like three or more way speakers. Much prefer a good two way with a first order crossover.

I have a Marantz AV recvr with some paradigms (on stands) all the way around. Home theater benefits from the sub, but I had to put all that in the closet, except the sub. Afraid my son was going to get a 40 lb speaker on the head. So for home theater we bought the Yamaha dsp type speaker. It's VERY acceptable. One box (with forty something drivers) over the TV. I'm real happy with it, and it's safe.

Are you familiar with Chesky Records?
If you can find something in their line up that you like, their minimalist recording style/technology is a real treat.

Dang, first time I've talked hi fi in years!

Oh, and that Mac stuff is probably worth more now than when it was new!

 

[Nimrod]

Nothing like the sound of music through vacuum tubes.

I never seen a McIntosh other than through magazines.......which I think I have a few laying around here somewhere.
Good luck fixing it.

The only tube amps I have are those for my guitars. The sound quality can't be beat.
But nowadays we buy machinery that do not not weigh 50 lbs. Instead we buy what can be held behind the ear and sounds like crap.

 

[BlindedByScience]

Postscript:

- Cheap Dremel knock off at Harbor Freight Tools....on sale for $7.95 (half price).
- Time to take about 0.030" off each flat.....about half an hour, going slow and checking with the Starett as it progressed.
- Seeing the knobs on the front of the "tuned up" audio component....priceless....

...system going back together now. Should have it soon.... :thumbs:

Cheers, guys - B.B.S.

 

[handyman dave]

Only 0.030"?! A simple mill cut #2 file would have done it in about 2 minutes apiece ... but I'm glad you found a way that worked well for you!

 

[MadMonk]

But Dave, that doesn't have a motor!
But I'm wondering if BBS wanted to leave the pots in the unit, making for a much more controlled operation.

Only 0.030"?! A simple mill cut #2 file would have done it in about 2 minutes apiece ... but I'm glad you found a way that worked well for you!

 

[handyman dave]

But Dave, that doesn't have a motor!
But I'm wondering if BBS wanted to leave the pots in the unit, making for a much more controlled operation.

Only 0.030"?! A simple mill cut #2 file would have done it in about 2 minutes apiece ... but I'm glad you found a way that worked well for you!

Boy do I understand about tools with motors. You should see my shop.
As a watchmaker & clockmaker I got pretty adept with files. I really think I could have done it with the pots in the unit. But I have to agree, an excuse to buy another tool with a motor is pretty hard to resist! (Besides, the tool might come in handy for another job one of these years. At least that's an excuse I have used.) :laugh:

 

[BlindedByScience]

I did leave the pots in the unit....in fact, I really tried to avoid taking them out.

The reason that I went with a Dremel knock off is that the front panel of these babies is plate glass, with gold leaf (on the back) lettering. Replacement cost on one that's 30 years old is likely to be several hundred dollars if you could find one, and the fronts on my two units are pristine. Also, there's an anodized steel bezel around the whole show and even bigger brushed steel end caps. I figured I couldn't get close enough to the panel with a file without scratching something, and I thought the Dremel would be more controllable. There's also my skill set to keep in mind......

I covered the front of the unit with blue tape and went at it.....slowly. Made measurement after measurement with the calipers and used a steel rule to ensure I was keeping the flat, flat. It all turned out great in the end. I upgraded a bunch of the RCA audio cables, and dug out some expensive speaker cables I've had in a box for years. Found one of the terminals on my speakers was loose, so they got taken apart as well. In fact, I just fired the system back up. Worth the effort; system balance and imaging are fully restored, and it's never sounded better. This calls for an AVO 80th and a beverage..... :thumbs:

....now I remember why I went back to engineering school.... :laugh:

Best regards, gents - B.B.S.

Edit - OK, so how funny it this; I'm cleaning up my bench in the garage, and my wife is looking at my new cheapo Dremel and figures out that she can touch up her acrylic nails by herself with it...!! She says; "....it's just like the nail techs use...". She's got the sanding drum on it, and is going to town as I type this..... :laugh:

 

[sack]

Postscript:

- Cheap Dremel knock off at Harbor Freight Tools....on sale for $7.95 (half price).
- Time to take about 0.030" off each flat.....about half an hour, going slow and checking with the Starett as it progressed.
- Seeing the knobs on the front of the "tuned up" audio component....priceless....

...system going back together now. Should have it soon.... :thumbs:

Cheers, guys - B.B.S.

Tom my man, you have the patience of Job.