When does a NOS capacitor get old.

[jlovda]

Curiosity question. Someone is selling sopposedly never out of the box C32 and MC2205 units on ebay for some wild prices. I have absolutely no connection with the seller and no interest in buying either unit. The amp is now 37 years old. Would a unit like this still need a complete recap to be on the safe side?

 

[MACKIE1975]

yes

 

[sKiZo]

Ceramics, PIOs, and film are pretty much bulletproof, but the clock is ticking on an electrolytic as soon as it leaves the factory ...

 

[c_dk]

In fact not using them makes it worse. The factory has to create the chemical reaction that creates the aluminum dioxide dielectric and just sitting causes it to dissolve. See the recent post about the amp owner blowing fuses on first turn on after years of storage.

 

[ybeauvais]

PIO bullet proof says skizo? Nope.

 

[ybeauvais]

Ceramics, PIOs, and film are pretty much bulletproof, but the clock is ticking on an electrolytic as soon as it leaves the factory ...

Nothing worse than idle time for caps, PIOs or electrolytic. Bumble bees agre TERRIBLY for onstance. Mylars age better as do ceramics. Time is not kind to paper in oil caps.

 

[miniman82]

Ceramics, PIOs, and film are pretty much bulletproof, but the clock is ticking on an electrolytic as soon as it leaves the factory ...

Right, tell that to the literally thousands of PIO caps I've replaced in TV and audio gear over the years. Old caps are guilty till proven innocent, by means of a rated voltage leakage test. But if you're going to the trouble to set up and test a suspect cap you'd just replace it anyway, faster in the end.

Even film caps aren't immune, everything goes bad if you give it enough time. I've seen mylars that were bad in TV sets because they were too close to a tube and got cooked. A good tech will replace if in doubt.

 

[Sam Cogley]

Depends on the PIO. Hermetically sealed steel/glass types (Sprague Vitamin Q, Soviet K40Y, the new Arizona caps, etc.) seem to last forever, but they weren't typically used in audio gear back in the day. Plastic case PIOs? Not so much in the "longevity" category. In the case of those grey Suzuki things, they're time bombs. Bumblebees just go out of spec, but are less susceptible to transformer-blowing failures.

 

[blhagstrom]

Old caps are old caps.
Old unused caps are worse. They like being used.

 

[Thocom]

^so they are kind of like a car, the worse thing you can do is let them sit?

 

[62caddy]

^so they are kind of like a car, the worse thing you can do is let them sit?

Yup.

 

[62caddy]

Saw those listings too. A photo of the seller with the owner of Audio Classics is shown in Kessler's McIntosh book. He's a big McIntosh guy. I wouldn't be surprised if he bought the units new.

At this point, they're pretty much display pieces only; surgery would kill their value.

 

[rollcentre]

Electrolytics gotta go at least. I don't replace film caps unless there is a good reason. I never seen inside these pieces so I don't know how many e caps are lurking..

Possibly the giant can caps could be reformed on the 2205... The multisection can caps on the other gear may be the most challenging to find exact replacements... cp or authenticap may have one with the same dimensions.

 

[jlovda]

Saw those listings too. A photo of the seller with the owner of Audio Classics is shown in Kessler's McIntosh book. He's a big McIntosh guy. I wouldn't be surprised if he bought the units new.

At this point, they're pretty much display pieces only; surgery would kill their value.

"Perceived value." They are listed for what the guy thinks they are worth. They don't have a sales history like a rare coin or vintage bottle of wine. As you mention, the units are doomed to stay in the box because the value would drop if they were installed in a working system. I predict the auction will end without a buyer unless there was some back room dealing. The seller should have bought a few extra C22's and MC275's and stuck those away in a closet.

 

[cduarte]

I'd agree with replacing the caps, especially the PIO and electrolytics, but as far as the units, I'd avoid the SS preamp and get a nice mx110 or C11 or C20. It'll sound far better than any SS preamp ever could, and gets you pretty close to an all tube system soundwise, especially with a rebuilt mc2105. BTW, if the input driver boards on the mc2105 are shot, it's far better to have McIntosh make you new ones than rebuilding the old ones and according to my tech, the new ones have radically improved circuitry over the originals. The cost is about the same, but you have about a 2 month wait. If you could hear my rebuilt MC2300 with my C11, it would make a believer out of you since they use the same input boards as the 2105 and an autoformer based MC SS amp with a tube preamp is just such a sweet combo.