Recapping a Marantz 2245. Change of original sound ?

Exactly. And you could likely use standard grade caps and still have a drastic improvement. 40 years ago there were no "audio grade" capacitors. My perspective is, you don't know what abuse your unit has been through unless your the original owner. Most of these components are ticking time bombs. Its like buying a 40 year old car with 100k miles on it and a fresh paint job, and expecting to drive it across country.

I agree. 40 years ago there was no computer grade capacitors in common use. Digital is very fussy about parts and capacitors had to step up to the spec.
Then computer controlled mass production made manufacturing and quality control much better. Caps today are light years ahead of the 70s tech and manufacture.

I'm not convinced about the whole "ticking time bomb" thing.
They are not that hazardous by a long shot.
I've never seen a unit blow up due to old caps and I have found many caps that were bad. It has always been a situation where the bad cap is causing noise, some a little noise, some a lot of scary noise!
 
If its ok with the OP, I would like to ask about mylar films. Are them the green porcelain (polyester)looking ones? I was under the impression that they were ok to leave in. i'll have to read pats shootout again.

I think the term ticking time bomb refers to their eventual failure/leakage. I did blow one up when i was a kid, Adjusting the watt output of a cb radio. I was twistin away at a pot, watching my swr meter and it scared the living crap out of me
 
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Many hours are spent "voicing" gear... A lot of sound is related to the design...but a lot is related to components.

Don't discount the amount of time Marantz and Smith spent on trying different components. They were a team... Marantz was the ears and Smith was the engineer.

But a lot of it is... Getting rid of different distortions added by the limitations of the components.

So, will new different caps change the sound from the original? Yes... But for the better or worse? Up to you to decide. As you are now "voicing the unit" yourself. But it will be better than worn parts.

2 more cents added to the pile... Know what they say "shavings make a pile..."
 
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I have a couple articles (one series by Walter Jung) about these other qualities of the capacitor. ESR (equivalent series resistance) and dielectric absorption are particularly important and I believe these degrade over time. These qualities also vary within a type (e.g. electrolytic) and across types (i.e. DA is much lower for ceramic than for electrolytic as a rule). I don't know how to post these into the forum but anyone that's interested can send me an email and I'll forward the articles to you.

Electrolytics more or less have a shelf life of 30 years. But of course their usable life will depend on usage, temperature, moisture, ect. The liquid in the electrolyte dries up which increases ESR and as time goes on will eventually short or blow out. If you going to re cap, do it thoroughly. The filters are a must as well as all the cans on the Power supply, amp, tone, and phono boards. I usually leave the FM boards alone if I have good stereo reception. But if you see one showing the signs, replace it.

I read an analysis a while back showing ESR, ESL, Dielectric absorption and harmonics of a different capacitors. And in the film category, the mylars lost. So I usually swap them out for metalized polypropylene. Just my approach.

Sal
 
Interesting view on the mylar caps. I got the exact opposite reaction from Terry Dewick when he worked on a MAC4100 for me. He felt that the mylar "box caps" were critical to the voicing of the unit and should not be switched out. Maybe personal preference?

Agree on the Mylar .... Not good for audio.... But Polypropylene are keepers.

I am not sure I would agree that a un-used cap will dry out... I have taken out 100s of 40 year old caps that are within spec for ESR. That does not mean I would leave them in there.

There are many many original tube units sound great even with the large milt section caps.

Then again, worked on some used units that just about every cap was toasted...that was a heat issue.

I think the "drying" process mainly is caused by excessive heat then venting or stressing the lead seal.

Quality of the seal and if the leads are spread or twisted or if it is being cooked....


just my 2 cents.
 
Interesting view on the mylar caps. I got the exact opposite reaction from Terry Dewick when he worked on a MAC4100 for me. He felt that the mylar "box caps" were critical to the voicing of the unit and should not be switched out. Maybe personal preference?
I'm sure this is a subjective matter. And I realize that what you see on a graph or chart doesn't necessarily go hand in hand with what you hear. But 40 years of advancement can't be ignored. Even if the design was perfect then, consistent production is another story. Control being the important factor. I will try to find it and post it. But it was an interesting read.
 
Mylar is a less perfect cap than several others. Given all perfect components, it would be impossible to voice anything by component selection, so I can see somebody liking whatever contribution the Mylar caps made. The problem is that these are really small effects. I can much more easily measure them, than hear them. In a properly designed circuit the imperfections should be minimized, so it wouldn't surprise me if nobody could tell the difference in a blind test.
 
I never liked the sound of Mylar... But you have to be really picky....

On the side of coin "shavings make a pile" , many small improvements add up...

Jk
 
...I'm not convinced about the whole "ticking time bomb" thing.
They are not that hazardous by a long shot...

Funny you say that, when you've seen a 30 year old large power supply capacitor punch a hole through a gyprock (plasterboard) ceiling at power-up you may change your mind. My face had just been over the chassis and I leaned back to power up the amp. It went off like a small cannon shot, spewing guts everywhere and I had to climb into the roofspace to retrieve the cap can. Never worked out why it did it. There were no faults in the amp.
I've never put my face over an uncovered amp at power on since.

I've seen plenty of receivers and amps where caps have exploded internally and I've had plenty of mini cap explosions over the years with computer power supplies, motherboards etc.
 
I'm staying away from you:yes:

"I've never put my face over an uncovered amp at power on since."

I think that would be good advice to follow!
 
As Norm Abrams says on TV, "And remember this. There is no other more important safety rule than to wear THESE- safety glasses."

Even a little tiny cap can go off like a bullet if reverse biased, and I don't want my eyeball to be the target.
 
I opened up a Pioneer sx-950 last night and want do I see... Blown out filter. It's only a matter of time. uploadfromtaptalk1437051007986.jpg
 
"Go read Investment Audio's total rubbish diatribe on his eBay site about why he doesn't recap.
Slick presentation that suckers buyers into paying big money for a Mickey Mouse "restoration".

That just about sums it up.

Its the opinion of these sellers that if the capacitor looks good, then it is good. It is an excellent example of using words that are very convincing to sell a product.

I have a friend with a repair shop that dabbles in transmissions from time to time. He sells his customer a complete rebuild, He takes them apart only as far as he thinks he needs to and slips a busted part, or set of clutches back into it, and puts it back together, installs it into the vehicle and calls me because it does not work right.

Every time, without fail, it has to come back out of the car, because he crossed his fingers and never inspected and replaced something he should have, but that would have taken him more time than he wanted to spend.
So even though he should know better, he continues to do a half ass job, and it bites him in the ass every time!

He continues to try to bullshit himself and no matter how much he wants to believe that something he never inspected would be ok, he just keeps smashing his face into that damn thing called the Truth.

So why, you ask, does he continue to do this... ??

Because he puts money before the product.
That lack of integrity, is why the rear seal on my engine leaks after he supposedly changed it.

If you do the little things right. The big things take care of themselves.

i am not suggesting that these sellers are lying about what they are doing, But it is in my opinion that they are lying about Why they are Not doing it.
Amen.
 
Funny you say that, when you've seen a 30 year old large power supply capacitor punch a hole through a gyprock (plasterboard) ceiling at power-up you may change your mind. My face had just been over the chassis and I leaned back to power up the amp. It went off like a small cannon shot, spewing guts everywhere and I had to climb into the roofspace to retrieve the cap can. Never worked out why it did it. There were no faults in the amp.
I've never put my face over an uncovered amp at power on since.

I've seen plenty of receivers and amps where caps have exploded internally and I've had plenty of mini cap explosions over the years with computer power supplies, motherboards etc.

Because in all the 100s on units I've looked into, I've never seen an exploded cap.

Never.

Not a single one.
 
I opened up a Pioneer sx-950 last night and want do I see... Blown out filter. It's only a matter of time. View attachment 611859

Did it still work?

Don't get me wrong, I know recapping is an excellent investment in dependability and audio quality.

I didn't say believe, I said know as in fact. I've seen many units work a lot better, actually fixed, with new caps.
 
Did it still work?

Don't get me wrong, I know recapping is an excellent investment in dependability and audio quality.

I didn't say believe, I said know as in fact. I've seen many units work a lot better, actually fixed, with new caps.
The unit had 3 blown outputs as well. It's singing now!

I don't want my words to be taken out of context. My "ticking time tomb" theory simply implies that these units are likely going to fail soon. The impact absorbed by your wallet, not your listening room [emoji1]

Iv seen plenty of filters with the vents blown, or a new vent created, but I haven't seen a cap turn into shrapnel since we used to plug them into the wall at tech school!
 
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