MC60 Pair to restore

Nice work! Did you need to replace any resistors?I have never worked with multi-section can caps.Is it easy to see how the old one was connected and re-connect the new multi-section can?
 
Thank you.
I've replaced only couple resistors so far. There is a still a 2nd amp to recap but I'm out of town and will do it in few weeks wen back home.
I do plan to run them for a while and check resistors again, as per David's suggestion.
I can see I'll need to replace a pair of 12kOhm 1% matched resistors as the old ones are "almost" within spec and new ones I bought are identical resistance.

Multi-caps are easy if you order new the same as old. I've done that before on MR71 and two Silvertone tube console radios with no issues. All you need is good photos or/and drawing of all wires connecting to Cap terminals.

In order to keep MC60 appearance the same, I used the 2 section (100/100 uF) multi-cans instead of 3 (80/40/20 uF); those were the only once with correct height of 4".
So, I had to add additional 22uF electrolytic for each Can, visible on pictures.
Some rewiring was necessary and I added couple of clamps you can see. That's all. Not a big deal now, and I am no experience in this, by any means.

Is that MC240 in your avitar? Very nice. I was looking for that (almost bought it years ago) or 275 but now ended up with two MC60's.
Are you looking for recap/restoration? There's ample info here, on AK if you need it.

Regards,
 
Well,
It's been a ful year now how I have restored this pair!
Time sure flies. :music:

MC60's are still in my main system in livig room with C36 as preamp.
Very lovely setup; it is used every day without any hickups.
Lately, I listen mostly clasic jazz and I think MC60 are great for that with great midrange and warm tones.
I am very pleased with this acquisition and I don't think I'll change them or at least any time soon.

Attached is the picture of the setup.
Regards.
 

Attachments

  • image.jpg
    image.jpg
    85.1 KB · Views: 67
Looks great!

I've got a pair of MC60's and I love them also. Great to see your project turned out the way it did!
 
Blow fuse

Well,
I spoke too soon! The other evening I got home after failing to fix my riding mower/tractor, turned on my system and Left channel MC60 was dead! :tears:
Needless to say, not a great day!
All tubes were out and when wife got home , told me a day before amp just popped when system turned on.

Hmmm :scratch2:

I took it to my basement office and took it apart. All looked good, all resistors measured well but fuse was blown.
Sure enough, after testing tubes, one rectifier tube was shot while output KT88's (1y new Golden Lions) show very strong.
Put a good rectifier spare pair and fuse and it's singing again. :music:

I 'll be looking for a set of new rectifiers. Door have any recommendation?
The old ones were old RCA 5U4 that might be original to the amp.

Thank you.
 
USA made NOS 5U4GB's are fairly abundant on e-bay and other sources and can be had for under $20 each so that's the route I recommend you pursue. I use either Sylvania or RCA's in my MC60's and MC30's and they usually last several years. You'll also find Sylvania made 5U4GB's marked Zenith, Channel Master, Raytheon, etc. NOS GE's are also good 5U4GB's.

Glad to see you have a tube tester. I would highly recommend to others reading this thread that you try to acquire a working tube tester like a Hickok or B&K if you use tube gear. I test the tubes in my amps 2 or 3 times a year for peace of mind. A local Hamfest is usually the best source for a tube tester at a not so outrageous price (under $250). Plus, the seller may be able to intelligently tell you whether it works or not. Check the AARL website for a list of upcoming Hamfests. E-bay sellers are getting crazy money for tube testers these days ($450+ for Hickoks) and the sellers usually have no idea if the tester is working properly or not.
 
Last edited:
You should be able to get NOS 5U4 rectifiers. RCA, Sylvania, GE, and Philips are all good for these amps. No need to get new Chinese or Russian. What your 60's really need now are a pair of LaScala's. Perfect match up.
 
Yes,
I have a Sencore Might Mite T28 tube tester.
It used to have some intermittent problems that I fixed but might need calibration, though. Nevertheless, one Rectifier tube was clearly gone.
I do have a few Spare Sylvania 5U4GB’s that I’ bought as NOS but they are not showing that “good” on my tester; therefore I’m reluctant to buy something like that on ebay.
Perhaps I should try some other venue or reputable seller. Thank you for the tips on tubes.
The tester really helped diagnosing the tubes that came with the amp; like really nice KT88 Gold Monarchs etc…

I drive a KEF 103/4 with my MC60’s; I’m a KEF fan, btw. These are reasonable size speakers which is important (WAF) as we use MC60s in our living room. My wife was really impressed with them and didn’t want them in my downstairs office where I initially placed them.
There I have KEF 105.2 and being low efficient speakers (85dB/Wm, IIRC) MC60 needed to flex their muscles more. I can tell my MC2205 meters going to 2-5W on normal-loud listening levels while the KEF103/4 would need around 1-2W, is so.

La Scalla speakers would definitely be too big in our living room. I never had experience with them except seeing few beat up examples in estate sales in past couple of years. I understand these don’t need much power but MC2205 seems powerful enough for my KEF105’s.

Thank you.
 
Back
Top Bottom