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McIntosh Mc60 restoration advice...how far to go

N

nortoncycler

New Member
Hi All, Long time lurker and first time poster who would appreciate your thoughts and advice on restoring a pair of MC60's I picked up for a soon to be winter project.

My initial plan was to do a more or less full'ish restore ... new electrolytic caps, switch the bias rectifier out, look to replace the bumble bee's, clean / refresh the paint and new chassis (given how rough the current ones are).. a few pics attached.
I bought these together as a set, but did not have the ability to see the inside until they showed up. I knew there was a slight possibility that they may be consecutive serial numbers, and in fact that's what they look to be.

So among other things, here are a few questions I would like your thoughts and advice on...

How common is it to come across a pair with consecutive S/N's?.. I know these came is at the very beginning of stereo so I imagine more than a few were sold in sets.. but far from all?
So does maintaining the S/N really matter? .. I suspect it may to some... and I personally think its a nice thing... but compared to having a nice looking set its slightly a bit more of a toss up.

Also as far as getting them back on their feet... I don't need "trailer queens" since I'm more about actually using them, however it would be nice to ..well... have them nice... so if it were you, would you:

1) Go ahead with plan A restore and re-chassis them with new chrome ones, write the S/N on the new chassis and hang on to the old ones for reference -knowing at some point down the road probable get lost
2) Or Plan B do the electrical restore but live with the "patina" of the original chassis to maintain the fact they are consecutive S/N... which, again to me, is cool..and maybe a bit amazing after ~65 years in the wild.

My other concern is that in their current shape someone down the road may look at them as parts units and there goes the set anyways.

I know it comes down to "me" and what I want to do... BUT... these guys were together before me and likely will be around after I'm gone.. so there is a bigger picture here I think I want to be cognizant of.

Thoughts, advice, suggestions all appreciated...
 

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I would restore electrically, possibly new sockets too, and see how they sound. This insides look pretty clean. Maybe powder coat the black bottom and have the tops sandblasted and either plated or powder coated. The chassis tops are pretty rough so I don't think you would lose much by having them refinished somehow. Your choice of course. The new SS chassis' on ebay are nice if you want to go all the way. Whether new chassis or refinish the amount of work is about the same.
 
Hi nerdorama thanks so much for the reply !...
You bring up some great ideas I had not thought of... including for the original tops... I saw some old threads on individuals who used to offer re-chroming for chassis, but it looks like maybe they are long gone? Wondering if anyone is aware of someone? or if going the new SS route makes better sense?
 
nortoncycler said:
Hi All, Long time lurker and first time poster who would appreciate your thoughts and advice on restoring a pair of MC60's I picked up for a soon to be winter project.

My initial plan was to do a more or less full'ish restore ... new electrolytic caps, switch the bias rectifier out, look to replace the bumble bee's, clean / refresh the paint and new chassis (given how rough the current ones are).. a few pics attached.
I bought these together as a set, but did not have the ability to see the inside until they showed up. I knew there was a slight possibility that they may be consecutive serial numbers, and in fact that's what they look to be.

So among other things, here are a few questions I would like your thoughts and advice on...

How common is it to come across a pair with consecutive S/N's?.. I know these came is at the very beginning of stereo so I imagine more than a few were sold in sets.. but far from all?
So does maintaining the S/N really matter? .. I suspect it may to some... and I personally think its a nice thing... but compared to having a nice looking set its slightly a bit more of a toss up.

Also as far as getting them back on their feet... I don't need "trailer queens" since I'm more about actually using them, however it would be nice to ..well... have them nice... so if it were you, would you:

1) Go ahead with plan A restore and re-chassis them with new chrome ones, write the S/N on the new chassis and hang on to the old ones for reference -knowing at some point down the road probable get lost
2) Or Plan B do the electrical restore but live with the "patina" of the original chassis to maintain the fact they are consecutive S/N... which, again to me, is cool..and maybe a bit amazing after ~65 years in the wild.

My other concern is that in their current shape someone down the road may look at them as parts units and there goes the set anyways.

I know it comes down to "me" and what I want to do... BUT... these guys were together before me and likely will be around after I'm gone.. so there is a bigger picture here I think I want to be cognizant of.

Thoughts, advice, suggestions all appreciated...
Click to expand...
Consecutive serial numbers could be a future selling point, but would probably lost if you have the chassis re chromed or go with new chassis (if they can be found). The re-chroming route has it's own pitfalls as I found out years ago with a Mc225. Finding a place that can and will do the job is the hard part. And then you need to have the lettering added back.....
I restored a pair of Mc60s many years ago. They were slightly different versions and in much better cosmetic condition than yours but I ended up selling them to get a Mc225.

I would however, ask a moderator to move your thread to the McIntosh forum here on AK. You'll get more "airplay" and many more opinions.
 
nortoncycler said:
Hi All, Long time lurker and first time poster who would appreciate your thoughts and advice on restoring a pair of MC60's I picked up for a soon to be winter project.

My initial plan was to do a more or less full'ish restore ... new electrolytic caps, switch the bias rectifier out, look to replace the bumble bee's, clean / refresh the paint and new chassis (given how rough the current ones are).. a few pics attached.
I bought these together as a set, but did not have the ability to see the inside until they showed up. I knew there was a slight possibility that they may be consecutive serial numbers, and in fact that's what they look to be.

So among other things, here are a few questions I would like your thoughts and advice on...

How common is it to come across a pair with consecutive S/N's?.. I know these came is at the very beginning of stereo so I imagine more than a few were sold in sets.. but far from all?
So does maintaining the S/N really matter? .. I suspect it may to some... and I personally think its a nice thing... but compared to having a nice looking set its slightly a bit more of a toss up.

Also as far as getting them back on their feet... I don't need "trailer queens" since I'm more about actually using them, however it would be nice to ..well... have them nice... so if it were you, would you:

1) Go ahead with plan A restore and re-chassis them with new chrome ones, write the S/N on the new chassis and hang on to the old ones for reference -knowing at some point down the road probable get lost
2) Or Plan B do the electrical restore but live with the "patina" of the original chassis to maintain the fact they are consecutive S/N... which, again to me, is cool..and maybe a bit amazing after ~65 years in the wild.

My other concern is that in their current shape someone down the road may look at them as parts units and there goes the set anyways.

I know it comes down to "me" and what I want to do... BUT... these guys were together before me and likely will be around after I'm gone.. so there is a bigger picture here I think I want to be cognizant of.

Thoughts, advice, suggestions all appreciated...
Click to expand...


I have had quite a few pairs of MC60s. Don't think I ever had a matching or close serial number pair. When these first came out, mono was all in vogue. When stereo hit, many folks simply picked up a 2nd MC60 to make stereo. Think I would replace the electrolytic caps and any leaky coupling caps and use as is for a while. Down the road, if you really like them then consider going through them with new or re-chromed chassis etc.

Also make sure you replace that 100uf 3V cap in the feedback circuit with at least a Nichicon bipolar 100uf cap. Better yet would be a .33uf film bypass on the 100uf cap. The stock caps are likely pretty dried out by now so will limit low frequency performance.
 
With the chrome bits corroded so bad I tend to agree with just having them powder coated or even a nice paint job. You can mask off the bit with the serial numbers. Even the raised logo on the side if corroded could be carefully cleaned or blasted, then painted. Leave the sides black and go with a color for the top. Hot rod red, champagne gold, etc. Those could make for a unique looking pair of amps.
 
I don't like those new SS chassis, it just seems like the amplifiers aren't the same after that job is done. If those were mine, I would just polish them and give them a coat of wax, and electrically repair/restore them. Sockets only if the old ones are bad.

Given the value of MC60s I seriously doubt anyone is going to chop these up for parts once they're in working order.
 
PakProtector said:
I'd not ditch the serial numbers with a restoration. Full on electrical, and clean up that leaves the numbers safe is how far I'd go.
Click to expand...
Agree completely with this. Sometimes you have to accept something the way it is, cosmetics-wise. One compromise might be to purchase polished SS chassis with the lettering, then have the original serial numbers stamped underneath. I would accept that as legitimate if I was a buyer. That's a lot of work though, stripping the old chassis and all, probably only worthwhile if you intend to keep them a long time. OTOH, it's also a lot of work replacing those tube sockets, and that needs to be done in any event. Decision, decisions...
nortoncycler said:
My other concern is that in their current shape someone down the road may look at them as parts units and there goes the set anyways.
Click to expand...
I think that's extremely unlikely. They're not that bad.

Jack
 
This is AWESOME!!!! I really appreciate the ideas here! So updated update? plan will be:

Cosmetics:
1) Keep original chassis in some form
2) Look into ways to refinish them w/o out disturbing the S/N and inspector codes underneath. - I did like maxhifi idea of just starting simple and seeing what a polish and wax may do - it may be enough for #66 to get it into a happy place, but poor #65...
3) I had never thought of the Chrome Paint (Thanks AudioAvarice) / Power Coating route so I took a look and I see where they offer a chrome like coating (Although Lavane's mention of Red has really peaked my interest in the color route), I did find a place not too far from me that does PC so I am planning to give them a call tomorrow to see if they can preserve the numbers during the process... If they can't then sanding and painting them myself seems like a good place to land
4) ramjet mentioned the lettering when re-chroming.... It would be great to have them silkscreen'd back on - just not even sure where to begin but I'm going to see what I can find... someone must be able to do it I would think?
5) Touch up the paint on the bottom cover and tranny's

Electrical:
Following what mcgjohn mentioned I'll check out the 100uf and add the .33uf film bypass - I would have never thought of this so really appreciate it.
Based on some of the feedback I've seen elsewhere at this point I am planning on going with the Auricap for the electrolytic replacements straight out of the gate.
Sockets.. I was going to DeOxit and re-tension them to start.. is there a criteria you use to say its time to replace them?

As TriodeLuvr said... decisions..decisions. :-) . But since I am planning on keeping these for a long time and they are a winter project I don't mind investing my time into them.

I am really appreciative for all of you helping guide me here in deciding on keeping the original chassis and how to approach it.

Side Note PakProtector... you mentioned updates? I'm certainly not opposed to trying out a few things as I'm guessing I can always revert the changes back to stock? If you have some I'd love to hear more...

​

 
nortoncycler said:
is there a criteria you use to say its time to replace them?
Click to expand...
Age. The metals weaken over time, especially with the temperature cycles these amps experience. I replaced all the sockets in my Citation V as the first step to restoration after the purchase a few years ago. I consider this an essential part of routine maintenance after 50+ years.

Jack
 
Thanks I appreciate the feedback... its one more thing for me to pay attention to as I go through them...I have yet to even closely look at their condition so that's going to point me in a direction.
Also if I do end up stripping the chassis to get them redone it may be a good opportunity to do a wholesale replacement...
 
maxhifi said:
For me if the sockets still grip tight, I keep them. I don't change them unless they're loose or damaged in some way.
Click to expand...
Old tube sockets often become noisy or intermittent even when they seem to be clean and tight. If the Mac loses contact with an output tube grid pin, it will self-destruct. I wouldn't take the risk.

Jack
 
Maybe try a paper towel soaked in vinegar to cover the crusty chassis. Oxalic acid might also be worth a try. Both will dissolve rust. Neutralize it with baking soda mixed in water.
 
gadget73 said:
Maybe try a paper towel soaked in vinegar to cover the crusty chassis. Oxalic acid might also be worth a try. Both will dissolve rust. Neutralize it with baking soda mixed in water.
Click to expand...
Never tried that before.. I've used Oxalic Acid on wood to remove the tannin stains but never beyond that... defiantly worth a shot to see! Thanks!!
 
TriodeLuvr said:
Old tube sockets often become noisy or intermittent even when they seem to be clean and tight. If the Mac loses contact with an output tube grid pin, it will self-destruct. I wouldn't take the risk.

Jack
Click to expand...
Thanks Jack ... seems like the safe plan then.. last thing I want to do in nuke an OPT ... I imagine that would be impossible to find a replacement for at this stage.
 
Salectric said:
One practical issue is the tube sockets have rivets rather than bolts. Removing rivets is a major pain and usually requires drilling.
Click to expand...
That sounds like a whole lot of non-fun ... any hints or tricks to accomplish it without damaging things? I was thinking of trying to punch them out but that maybe a recipe for disaster?
 
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