Why re-cap? Once and For All.

blhagstrom

Mad Scientist, fixer.
Subscriber
After watching the debate go on for years, wondering myself at first, reading threads where the Master's came to believe, finding documents from the cap manufacturers, doing many re-caps and experiencing the results and finding issues while re-capping, I'd like to post a thread that becomes the "link to" once and for all.

Subject: Marantz 2015.
Condition as found, working for the most part but FM on the tuner had an issue.

I found a transistor on the tuner with rotted legs, repaired that and FM works fine.

Unit is in good cosmetic condition and I set it aside to do a restore and flip for profit.

I just went through the unit and found 4 electrolytic capacitors with obvious problems.
After the re-cap, one channel was weak and lousy.
I could see that someone had been hacking around in there, the solder jobs were obvious and a wire had been cut and re-attached different than factory.

I FINALLY found that a capacitor had been added to the trace side of the tone board, similar to a factory mod, that was the problem.

The bad caps I found were in the power supply and on the main amp.
I am surprised it worked as well as it did.

Well, NOW it works.

Since the manufacturers flat out say electrolytic caps have a shelf life. They explain why the deteriorate (dry out). I've seen enough problems directly related to electrolytic caps on "working" gear to know, you cannot trust them.

The argument "if it works, don't fix it" is wrong. It may "work", but its not right.

Here are the caps I found in a "working" unit.
FWIW, I have found "rotted" caps like this in Marantz gear before. Most of the gear "worked" some had issues but the only way I found most of the bad caps was during a full re-cap. Once unit I accidently found it by pushing the cap up right and it seemed too loose. Just dumb luck on that one.

Here is what hides in "working" units.

IMG_4461.JPG
IMG_4460.JPG



Re-capping is a lot of work.
It's worth it on anything you like.
It's in the multiple $100 because of the labor and skill.

And, I've done many tuners and they all work better. I do not have the tools or skill to re-align.
I have seen $600 tuner bills and not one damn electrolytic cap was replaced, so I really have my doubts about THAT!

Now, I need to go listen to a nice fresh restored Marantz.

That works!
 
Thank you for this. I think some of the anti-recap rhetoric comes from guys that re-capped a problem unit hoping it would fix it and it didn't, so they reached the (faulty) conclusion that the caps were okay.
 
The argument may be right. But it's weakened by choosing as the main example a Marantz that had been butchered by a previous owner.

A better example would a component in immaculate, original condition, seeming to work properly, and why it still needs a full recap. That would be very persuasive. The existing example is not. It's not yet "the 'link to' once and for all" that you intend.

I have several very good components in original condition and working beautifully. I know the caps are near or past their expiry date and I want to be persuaded.
 
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The argument may be right. But it's weakened by choosing as the main example a Marantz that had been butchered by a previous owner.

A better example would a component in immaculate, original condition, seeming to work properly, and why it still needs a full recap. That would be very persuasive. The existing example is not. It's not yet "the 'link to' once and for all" that you intend.

I have several very good components in original condition and working beautifully. I know the caps are near or past their expiry date and I want to be persuaded.

It wasn't butchered.

It appears they were trying to locate the real problem.
The real problem was bad caps.
Once the bad caps were replaced, the "fix" caused problems.
This unit was all original except for where I could tell they had been trying to isolate a problem in the channel.

This is a perfect example of why re-capping makes sense.

Every unit I've ever re-capped was original.
Most appeared to "work" well.
Some had issues beside bad caps and while fixing those, I re-capped along the way just because I was already there and hunting bugs. Once fixed, I simply finished the re-cap so it was all done.

Every single unit I ever completely recapped worked better.

I wondered myself for years.
I found old threads where our best tech masters doubted at first.
Once I actually found the tech sheet from Corner Dubner, that was proof.
It is not uncommon in other industries to replace e-caps as maintenance.
AC units, motor start capacitors are commonly replaced.
Tube gear, its just a given to recap before real problems appear or to correct real problems.

There is no valid argument against doing it.

The caps I'm showing here came from a "working" unit.


.
 
Thanks for your corrections. Maybe I misunderstood this sentence —

"I could see that someone had been hacking around in there, the solder jobs were obvious and a wire had been cut and re-attached different than factory."
 
Thank you for this. I think some of the anti-recap rhetoric comes from guys that re-capped a problem unit hoping it would fix it and it didn't, so they reached the (faulty) conclusion that the caps were okay.


There is that mistake and I've started to speak out against re-cap to fix thought.
Re-cap may help minor issues or poor sound but it's not a true repair method.

What gets me is the BS about original parts being the "correct" parts for the "original" sound.
I see that "used car salesman" crap on eBay.
Pure snake oil.

The sound is in the design, not the parts.
Original tires don't make a sports car a sports car and using them is not seen as smart.

The only valid point I will entertain is one where someone doesn't like the sound after a re-cap.
I contend that either the re-cap was not done well or once restored, they don't like the sound of that unit.

There is a lot of difference between brands and models.
Toss in the differences in speakers and its very possible a tired old dirty noise floor unit did sound better before the rebuild.

One of my favorite amps has a really nasty dirty noise floor.
I am not going to recap it.
 
Thanks for your corrections. Maybe I misunderstood this sentence —

"I could see that someone had been hacking around in there, the solder jobs were obvious and a wire had been cut and re-attached different than factory."


I was trying to say that someone HAD made an effort to find a problem and had made a patch.
Probably a service tech paid by the hour and just getting out the door.
The point is, the problem WAS bad caps. The ones I found re-capping.
One of the caps with a rotted off leg came off the main amp.

How this unit worked as well as it seemed is mysterious.
But, I've seen rotten wires work and when disturbed fall apart.

I saw NV power pull the neutral line off the power main to my house in Vegas just trying to pull the connection up to inspect it. Big 1/2 inch wire, so rotted it just came apart.

I called them because my lights flashed once running the washer.
 
I don't have the capacitor tech sheet handy.
But, here is a link to Cornel Dubner web site that has "lifetime" calculators.
http://www.cde.com/technical-support/life-temperature-calculators
NOT that I mean "here is a tool to use", just to point out that e-caps HAVE a lifetime, its a known thing.

They are a wet chemical device. The electrolyte exists to keep the aluminum from oxidizing.
It's a fact that aluminum oxidizes, just like iron rusts.
Moist things dry out.
No seal is perfect.
Age never stops.

Best movie line? Time is the fire in which we burn.
 
The sound is in the design, not the parts. Original tires don't make a sports car a sports car and using them is not seen as smart.

Exactly so. Nice analogy.

Should a component adds a "sound" to the circuit, then the rebuilder has simply found another way to fail.

Yet this does not stop people from crowing about the "improvement" from using distorting components and then analyzing the new sound in glowing terms used for wine, chocolate, or beer, instead of those describing the odors of sewage treatment plants, durian, and certain cheeses.

Viva la straight wire with gain!
 
I will replace caps without testing them as preventive maintenance and to improve performance. Have a pretty good tester and will test them at times afterward , even if it was working and found them to be out. Plus as a cap ages it will pass DC and have resistance.
So in general if it is a nice vintage unit, throwing $10~$20 of parts into it does not seem so outlandish. Place any cost on the back end.
Some techs just want to replace the bad parts, is this do to wanting return business? Get to the next unit? Another unknown reason reason?
I don't care they are not me. lean towards doing preventive maintenance.


Barney
 
I’m definitely a fan of recapping and overall restoration. Too many benefits to ignore and relatively cheap if doing it myself.

What gets me is the BS about original parts being the "correct" parts for the "original" sound.
Over the past few years I’ve definitely developed an opinion on this subject. If anyone in the world has accurate sound memory dating back to the 1970’s I’d like to meet them. Seems far fetched. I’ll concede that sounding good is subjective but sounding original isn’t possible to quantify.
 
The only reason I'm hesitant to suggest a blanket re-cap, particularly on SS gear, is that often its done with the intent of fixing problems without doing the diagnostic work too. Also, and sorry if this offends anyone, but it is frequently suggested by or for folks that may not have the technical skill to pull it off correctly.

Personally I like to evaluate and diagnose first, that way I know what I'm working with and be able to judge whether the fix is appropriate. Sometimes the answer is new caps, sometimes its not. The last few things I've had with odd "it must be caps" problems were actually leaky transistors. I did fix both of those pieces, then re-capped them as a preventative measure just for age reasons. Both were pushing 50 years on original parts and I thought that was enough.
 
is that often its done with the intent of fixing problems

ive had 15 ( 40-55 year old) recaps, only 2 were done in hopes of improving the sound because they just didnt sound as good as knew they should and there was a noticeable improvement after. the other 13 sounded good before and had no issues i just had them done because ive read enough articles and studies that i dont trust 40 year old caps and am hoping they will keep going another 40 years and i was confident they wouldn't sound any worse after and none did. i had the speakers relays, known transistors and diode issues done as well. after i feel that they are sounding the way way they were intended to, where before i was never sure.
 
Many folks just don't want to pony up the dough for a full recap.

If you do it yourself the parts cost is minimal. If you're paying someone else to do it the labor cost can be high, depending on the unit, i.e. power amp vs receiver.
 
Well, I'm glad this is settled once and for all.
Umm... maybe not yet...

I 'd love to recap the great vintage amps I love, just to extend their lives. I can do the work, just need a couple new tools, so it would only the cost of the caps. But I read/hear so many tales of recaps gone bad. Chrisxo's comments are very reassuring — 15 full recaps without one dud: that's a big sample size.

But a friend of mine recapped his power amp. Don't ask me for details because I don't have them (a) it was years ago (b) he was only a casual acquaintance (c) I wasn't involved (d) I'm not even sure what amp it was — a think a fairly rare Marantz Esotec SM-1000 he always bragged about, thought was heaven on earth, and it deserved the best.

He replaced every cap with a Hovland cap, each one handmade to the highest standard with the finest materials — and when Hovland didn't have the right value he used them in parallel or series to stay within very close tolerance. Hovland caps were very expensive — each one could feed a family of four for a week (not the caps, the money).

When he was done, he told me the amp sounded TERRIBLE! He'd ruined his beloved amp! He ran out of adjectives to describe how bad it was, even after twenty adjectives we're not allowed to use here on AK.

He took out all the Hovlands and put the old ones back in. He was back in heaven — but staring at a pile of Hovlands, which cost him a small fortune, and were now "used", with a resale value of ?????

That's only one anecdote of one recap failure. Chrisxo offers 15 anecdotes of 15 recap successes.

But it does demonstrate, pretty dramatically, that a recap can go wrong. That might happen to mine. I'm sure you can all understand why I'm a little bit uncertain...
 
Chrisxo's comments are very reassuring — 15 full recaps without one dud: that's a big sample size.

well if i would have done them myself im sure everything would have gone to hell, but i had people that knew what they were doing do it ;) im lucky for most of my SS stuff i have a friend that used to own a TV and Electronics repair shop, closed it a few years back and now just enjoys doing this vintage stuff in his garage and hardly charges me i keep trying to pay him more but he wont take it . my tube gear i take to HI FI Sound and they are a bit pricey though but top notch i had a restore done on my Model 9's even though almost everyone i asked said i should keep them original and they sound wonderful and im glad i had it done.
 
I also claim a number of recaps without one dud - 21 to be precise - Sansui integrated or power amplifiers, one receiver, two tuners (partial), and one pre-amp. I am definitely in the pro-recap camp - but only if 'recap' doesn't mean just changing the electrolytic capacitors and doing nothing else.

With a significant number of the above I didn't feel it necessary to change the main power capacitors - so I left them alone. The vast majority of the units had some kind of problem beforehand, all serious problems were resolved first.
 
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If it has symptoms it's broke by definition. If it doesn't have symptoms - that's where philosophy enters into the equation.
 
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