McIntosh MC60 60Watt tube Mono-blocks worth restoring?

Levi · « **on:** 12 Feb 2007, 09:32 pm »

Hi All,

I have a pair of McIntosh MC60 Mono-blocks sitting in my garage for awhile now. They are rated 60Watts each of tube power which is pretty powerfull during the days. The MC60 is still working with Genalex KT88 Gold Lion tubes but may need some reconditioning. Cosmetically, it is 80% good with slight corrosion on the plates. Definitely it needs a good cleaning. I contacted audiolab and other various McIntosh recommended electronic repair shops in my area and they priced it between $400-800 each to fully restore the unit.

Do you think it is worth the time and expense?

TheChairGuy · « **Reply #1 on:** 12 Feb 2007, 09:39 pm »

Gulp - a bit pricey particularly as they are working.

I had my ancient Dukane 50watt monoblocks restored (one was working, one was not and both needed strain reliefs, biasing & caps) and I paid under $500 for the pair. They were done by the local McIntosh repair facility....wonder if they would have charged my more if these were Mac's I brought in. Don't know if your price included new tubes - mine did not (I bought them myself at additional $150.00 total or so)

I don't live in the sticks either - just 8 miles from (pricey) San Francisco proper.

I'd keep shopping around until you find something closer to $500.00. Metro-NY shouldn't be much different priced then here, comparitively

jon_010101 · « **Reply #2 on:** 12 Feb 2007, 09:46 pm »

Monoblocks are pretty easy to restore from a labor perspective. $500 total sounds more typical for a basic restoration, but much depends on the parts quality/quantity. There are a lot of capacitors in a McIntosh amp, which could make it a bit more $$$ than some simpler amps. I'd be sure to see what they intend to install -- for example, if they are using standard "orange drop" coupling caps, then $800/amp is quite high. Really, a lot of variables to consider. I'd go for the best combination of price/parts quality.

TheChairGuy · « **Reply #3 on:** 12 Feb 2007, 10:19 pm »

Yeah, mine were Spragues and some other (Sprague, in some values, were not available) fairly mundane (priced) caps.

zacster · « **Reply #4 on:** 12 Feb 2007, 10:29 pm »

Levi

Since we now know they both work just fine with the one remaining set of tubes, get a new set of tubes for the second amp and give it a try in your apartment with your speakers. You WON'T go back. In fact, you'll hate having to part with them to have them worked on. Trust me on this.

If you don't think they're worth it after that bring them back to my house and I'll use them!

BTW, I'd consider doing a basic restore on them for you, new caps, diode, maybe new sockets, new terminals, new rca, new fuse holder on the broken one, and a switch in place of the AC outlet on the chassis. No circuit changes, just replacements. And it will take time because I can only work on it in small bites, but you have them sitting in your garage now so maybe you don't care about how long it takes.

Zac

SET Man · « **Reply #5 on:** 12 Feb 2007, 10:33 pm »

Hey!

Levi, $400-800 each?

Now that is a bit pricey and likely that they will just put cheapest caps they could find in them.

If they still working than that is a good start.

Most old tube amp that age would likely need some new caps for sure. Those resistors in there should still be good... unless you want to change them to better one like Caddock.

As for the cosmetic side of them.... if they aren't that bad than that is no need to stripe them down and refinish them.

Hey! Maybe it is time for you to swing a soldering iron and make this your weekend project.

Seriously... I could help you with this if you want. I'm sure that we could find schematic for them on the net somewhere.

Take care,
Buddy

Levi · « **Reply #6 on:** 13 Feb 2007, 01:08 am »

Thanks John, the price does not include new tubes which I have to take into consideration before bringing it to use. I am not sure if I should use Spragues. It is a new vocabulary to me so and sounds expensive.

Jon, I will look into getting quality parts but not exotic. Audioclassics is expensive. They are highly recommended by Sharon butt of McIntoshLabs. They are probably the Kevin Deal of McIntosh service.

Zac, I have taken enough of your valuable time. You and your wife are very generous and kind. Thank you. I will save up and have it done by a shop eventually. I will keep you up-to-date.

Buddy, $400-800 a peice is a bit high for me. I would also need new tubes on top of that. I found Circle Stereo located in Texas will do a complete restoration for $349.49 . I hate to ship the amps to Texa$. Thanks for the offer.

If I get the project started, what do you think I should use? Nichicon electrolitic capacitors, Mallory tubulars or I just ship it to Texas.

Here is what Circle Stereo would do.

SET Man · « **Reply #7 on:** 13 Feb 2007, 01:30 am »

Hey!

Levi, Spragues cap are very nice... similar to those used in old tube amps of 50's and 60's.

I see from the picture. Instead of getting a new electro can caps he use new caps underneath the amp to preserve the look of the amp above. Yes, you could get some Nichicon or even some Blackgate if you want to spend more money.

I see Orange drop caps... likely use in signal path. Not a bad cap actually I used some in my '67 Akai R2R. But of cause you could go for nicer caps like Auricap, or PIO Jensen

Oh! look what I found on the net....

http://www.drtube.com/schematics/mcintosh/mc60.gif

http://personales.ya.com/lcardaba/schematics/mcintosh_mc60.htm

MC60 schematic!

Levi, I think you should restore them yourself and save some money. And if you need help just let me or others here know.

I'm sure they will sound great with your Sonus Faber

Take care,
Buddy

dB Cooper · « **Reply #8 on:** 13 Feb 2007, 02:16 am »

If my name was Sharon Butt I'd definitely change it.

Levi · « **Reply #9 on:** 13 Feb 2007, 02:19 am »

Thanks Buddy. The circuit does looks simple. I just have to get the correct service manual so I can find the correct values for the components. It's a project that's for sure. I am not sure if it is worth the time and expense. A good condition goes for $1500 for both pairs.

Levi · « **Reply #10 on:** 13 Feb 2007, 02:19 am »

Her email is SButt@...

Quote from: dB Cooper on 13 Feb 2007, 02:16 am

If my name was Sharon Butt I'd definitely change it.

SET Man · « **Reply #11 on:** 13 Feb 2007, 02:27 am »

Quote from: Levi on 13 Feb 2007, 02:19 am

Here email is SButt@...

Quote from: dB Cooper on 13 Feb 2007, 02:16 am
If my name was Sharon Butt I'd definitely change it.

Hey!

I hope Ms. Butt's system have a nice bottom end.

Levi, BTW... the caps, resistors and etc values are listed on the schematic... I think they are worth it.... go for it man!

Take care,
Buddy

zacster · « **Reply #12 on:** 13 Feb 2007, 03:54 am »

I would use a mix of caps, depending on the position. For the coupling caps I would spring for Auricaps or something at that level. For the PS, because of the sheer number of caps there, I wouldn't go crazy. Each of the can caps is 3 values, and there were a few others too. Figure $10-20 each for Black Gates and you're looking at a lot of money. That's one problem with this amp. It is totally overbuilt. I guess when your goal is 10wpc you don't need beefy power supplies like that. I wouldn't replace resistors unless they test bad/out of spec. Use teflon wire, but not silver, just copper of decent quality. Some people don't like silver anyway. I wouldn't know because I've never used it.

Get rid of the selenium rectifier, that's gotta go. New sockets, they don't last forever. And new connections. Those were the worst part of the amp but we made it work.

Also, whatever you decide, don't get caught up in which cap is the 'best' for the application. One substitution won't make a difference, except the coupling cap. I used the same yellow caps in my TV when I rebuilt it. They're fine. And modern caps are smaller than the old ones so space isn't an issue, but from seeing the inside space isn't an issue anyway.

And really, I would do it. You pay for the parts, I'll do the work, either on my own or with you if you want to learn (talk about the blind leading the blind). I'll take something as payment. It won't really take all that long either.

Scott F. · « **Reply #13 on:** 13 Feb 2007, 04:13 am »

Hey Levi,

Not sure if you are aware but recently a quad of the Genelex KT-88's (which tested strong and that were made in England) just sold for $1000 of eBay. If you've got access to a tube tester, the Genelex's may finance your rebuild.

Checking eBay further, a pair recently sold for $2800. They didn't state if they had been rebuilt (re-capped). A single (mono) amp sold for almost $1400 (with a few new caps).

Most of the hardcore Mac guys out there don't want them altered. If I were you I'd take them to a local guitar shop (or audio shop if you have one), let them bring them up slowly on a variac. Many, many times you can get those old caps to reform and hold if you bring them up very slowly on a variac. Then let them test the tubes (don't let them change them) and rebias the amps. Clean and polish them then put them on eBay.

Unless you really want to use them, I'd let them go to the fanatics on eBay.

Levi · « **Reply #14 on:** 13 Feb 2007, 05:31 am »

Hi Scott, thanks for the info. I highly doubt if I would part with the amp and those Genalex tubes. I've been wanting to restore the amp but never find the time and motivation to do it.

I brought the amps to Zacster last Sunday to check the amps if they are working. As you suggested, We plugged the amps into his variac and slowly brought it up to 110V. Prior to that, Zac already printed the MC-60s schematics and some specific values. We traced the circuit, disconnected the Selenium rectifier and we measured the values of some specific circuits. We were getting different values than the one Zac found from the internet. We figured they were from a different variations of the amp. We concluded the circuit were good since we were reading values, fuse not blown and no sparks. Long story short, we connected the amp to a speaker, source, preamp and we have music! The amp actually works. Mission completed!

As for Zac, you are a true gentleman!

Levi · « **Reply #15 on:** 13 Feb 2007, 05:49 am »

The MC-60 amps have been sitting in my garage for several years without seeing electricity. I was very suprised to see sparks when Zac accidentally shorted the input jacks. Those original capacitors are good! So what's the fuss?

I planned to put the MC-60 back into service. It needs reconditioning for safety and reliability.

Levi · « **Reply #16 on:** 13 Feb 2007, 06:08 am »

Hi Zac,

I just might take your offer. Perhaps, you can show me how to do one side and I can do the other half. The picture from the Circle Stereo looks pretty simple and inexpensive. What parts do I need replacing?

Levi

SET Man · « **Reply #17 on:** 13 Feb 2007, 06:33 am »

Quote from: Levi on 13 Feb 2007, 05:31 am

Hi Scott, thanks for the info. I highly doubt if I would part with the amp and those Genalex tubes.

Hey!

Wow!

If those still good and test like new or nearly new than you are in for a treat Levi.

Take care,
Buddy

lonewolfny42 · « **Reply #18 on:** 13 Feb 2007, 06:38 am »

Levi....I don't think you could stick the McIntosh in your new audio cabinet....

zacster · « **Reply #19 on:** 13 Feb 2007, 01:17 pm »

Unfortunately one of the KT88s was broken. At least 2 of them are good, and the third may or may not be good, but it wouldn't have a match. Maybe buying a used single would be the way to go if the third one is good. If not, I'd say buy a matched pair of the new production clones. They go for about $100-150/pair.