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Re-Capping

greybeige

greybeige

Active Member
I've been very intriqued by the discussion of re-capping old amps and speakers. Can you describe the nature of the sonic change that results? I have a 2270 which to me has a very fine sound already and was refurbished to a minor extent (lamps, switch relay) but I think it still has the original guts throughout. How extensive is this project and can a relative novice pull it off? I play this through a set of 1975-era JBL 4311's and I understand the crossovers could be re-capped on those too. Teach me! :banana:
 
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Capacitors age at different rates depending one the material used, the sealing methods and the ambient heat when in operation and the length of time it has run at that level of heat.

Sonic improvement you should expect, in general terms are:

- Bass: Better slam, definition and punchiness, depending on source material.
- Imaging: Far more stable stereo imaging, resulting in increased clarity of voices and 'air' around the performers.
- Highs: Far clearer and defined instrumental presentation, close-mic'd instruments appear to jump out at you, if you've got the right speakers that are positioned correctly.
- Top-to-bottom sonic presentation: All frequency spectrums will be more distinct. If you swap out a source component, you'll start hearing differences in different models. In other words, you should start hearing back through your system into the source components.

Do the speakers, too, its worth it for most speakers over 20 years old. For receivers, the biggest challenge in re-capping is the cost of labor. The parts aren't that bad. Some receivers are a pain to pull the boards on without breaking wires or doing other collateral damage as you re-cap. This is what drives up the cost and causes some folks to shy away from doing it.

Cheers,

David
 
The 2270s tend to run very cool if not in a wood cabinet. Which helps prevent the caps from aging.

2270s have very few electrolytics over all and even fewer in the signal or feed back paths.

So unlike some units they do not degrade as much and would not improve as much with a recap.

My 4400s had many more capacitors and run much hotter. They really benefited from a re-capping.

The early 2270s had smaller 6800uF main filter caps. My 2270 is an early one. I adder capacitance to the main filters and wow did that make a difference to the bass. Also, you can add a .1uF bypass to the mains and that help hi feqs.


I would not discourage a recapping of a 2270. Just be wise and thoughtful of how you go about it.


Here's a shocking simple improvement.... Look at the power plug prongs... Are the tarnish? Clean them till they shine.... Then do the recap....


johnk
 
First of all, I am not a tech and not very knowledgeable about the specifics, but recapping older (i.e. more than 20 years old) gear makes sense to me. I had my Sansui AU-D11 II completely recapped and noticed a significant improvement in sonic qualities. I think the degree of improvement you notice will depend to some degree on how much the old caps have degraded, and the quality of your system.

But there are also those who think recapping alters the "vintage" sound, and believe that caps should not be replaced unless they are bad.

There is a very long discussion among members of these different camps "stickied" in the Sansui forum HERE.
 
Re-capping a receiver like a 2270 involves somewhere around 80 electrolytic capacitors, give or take. If you have good soldering skills and are happy doing meticulous work then you may be able to do it yourself.
Mark every cap that you are going to replace with something like a sharpie and note it's value and case style. Don't just go by the list in the service manual, it may be inaccurate due to production changes or errors.
Try to get the new main filter caps that dimensionally match the old ones as close as possible so that they will fit in the mounting hardware with little or no modification. Sometimes this is difficult to near impossible.
When you get the list together, order good quality 105 degree C. rated parts from a reputable supplier like Digikey, Mouser, etc. New parts are much smaller than the old ones, go up a voltage step or two to keep the size similar.
When you start replacing them, note the polarity of each before you pull it from the board. Sometimes the marking on the board is wrong.
While you've got it apart, this is an excellent time to clean the controls and switches.
Test frequently so you will know where you screwed up.
When there are no caps with sharpie marks left on them, stop!:D

Or just have me do it.

Tom
 
As long as you are replacing the old cap with a new of like value, quality ( or better) and type....its very unlikely that you will change the sound from the way it was originally designed to sound. But it will improve it over the degrade sound due to age.

However, tantalums tend to sound harsh. I avoid put tantalums back in when ever possible. This will change the sound, but for the better.

Does this mean we should use the crappy interconnect wires they used back in the 60s and 70s? I just picked up a great tuner,preamp, amp and TT from 60's.... I laughed at the interconnects they were using....I am using modern interconnects and not thinking twice.

Check out some of the old tube amps and preamp. Most of the caps used in those unit were the best sound caps period. I have a model 7t and they used some really good caps in that unit.


If you read up on caps and then when you look at the units that "sound" very nice....9 times out of ten its because they used the right cap in the right spot..or used great caps everywhere...and did not use cheap ones....among doing other important things....


Here are a couple links that may help explain the affect of caps on sounds.

http://members.aol.com/sbench102/caps.html

http://web.archive.org/web/20030807...ors.com/picking_capacitors/pickcap.htm#tuning

My opinion, if you read and study the links above....you will learn how to get the highest quality CAPACITOR SOUND at a bargain price.

I will have to read the Sansui sticky....

johnk
 
catrafter said:
Re-capping a receiver like a 2270 involves somewhere around 80 electrolytic capacitors, give or take. If you have good soldering skills and are happy doing meticulous work then you may be able to do it yourself.

Tom
Click to expand...


I would have to dis-agree the 2270 has less than 20 electrolytics..... in the Amp and pre-amps. Most people do not recap the RF sections unless a failure requires it.

jk
 
jstang said:
I would have to dis-agree the 2270 has less than 20 electrolytics..... in the Amp and pre-amps. Most people do not recap the RF sections unless a failure requires it.

jk
Click to expand...

You are right John, if you're doing it for yourself, you can replace the most failure prone ones and get the others as they fail.

On the other hand, consider how upset you would be if you shipped your unit halfway across the country for restoration and a week after you got it back some 20 cent cap on the FM multiplex board shorted and you had to send it in again for warranty service.
You'd be unhappy, and I'd be even more unhappy! :tears:
I just replace them all and sleep a little better.

Tom
 
jstang said:
As long as you are replacing the old cap with a new of like value, quality ( or better) and type....its very unlikely that you will change the sound from the way it was originally designed to sound. But it will improve it over the degrade sound due to age.
Click to expand...

One of the things that has kept me back from recapping my 2250 is my lack of knowledge of "good" versus "bad" cap suppliers. I understand Blackgate was good, but they went under. I'm always wary of parts suppliers, since it is hard to determine quality from a picture or description, although the most telling thing for me is place of manufacture. I would be more keen to buy Japanese caps or USA caps over China caps, but that's just me. My 2250 doesn't have all too many electrolytic caps, and with the modular boards and a service manual, I would feel comfortable doing it on my own sometime.
 
Just read thru the Sansui Recap post... I did not read every line....

That post is much about life expectancy of electrolytics, which is critical to your typical 70's unit. Little time was spent on the "sound of capacitors".

On my home made mono blocks and preamps... I followed the advice in the Picking Caps url....many many moons ago when that article first came out... At the time during school, I worked in an electronics supplier and surplus dealer.

I had access to every type of cap at FREE cost.... They would buy the stuff surplus by pennies on the pound.... So, I was able to hand pick every capacitor I used in my mono blocks. I was able to try different types for each location in the circuits. At least each had two types tried....... I almost always preferred the sound of polycarbonate followed by the other film caps. But finding the values you need can be difficult...unless you have access to them by the "pound".


jk
 
jstang said:
I would have to dis-agree the 2270 has less than 20 electrolytics..... in the Amp and pre-amps. Most people do not recap the RF sections unless a failure requires it.

jk
Click to expand...

There is no reason to not recap the tuner section, the electrolytics in a tuner are for filtering/bypassing/coupling only.
 
PS Bypass Cap?

JSTANG made a comment, "you can add a .1uF bypass to the mains and that help hi feqs." Would someone elaborate on this comment and specifically explain where on the 2270 PS, this bypass capacitor would be installed?

If it helps the high freq's, then a 20 cent part makes this mod an exceptional value. Appreciate any comments. Mike
 
MikeED said:
JSTANG made a comment, "you can add a .1uF bypass to the mains and that help hi feqs." Would someone elaborate on this comment and specifically explain where on the 2270 PS, this bypass capacitor would be installed?

If it helps the high freq's, then a 20 cent part makes this mod an exceptional value. Appreciate any comments. Mike
Click to expand...

Well, it's not a 20 cent part, but it does help high frequencies. I've always seen a film cap used (like a Solen or Dayton from Parts Express), but those are more expensive than electrolytics. The cap goes across the terminals of the big power filter caps, with one film cap used per supply cap. I did this mod on my 2250 and found it to be a big improvement in sound, especially for the cost and labor (pretty minimal) involved.
 
Thanks for the info regarding the bypass caps on the 2270 power supply.

Being relatively new to this forum I do have many questions but will stick to the orgional subject matter of this topic. From what little I have read I'm assuming that mylar capacitors should be replaced by metalized polypropylene for better sound reproduction. Question: Is this statement true for all signal and coupling circuits in a receiver/amplifier?

Now for an unrelated stupid question: When installing new power transistors (TO-3) on to the heat sink, should a "thermo pad" be positioned between the tranny and heat sink? Never did this before so bear with me...thanks much. Mike
 
MisterFishey said:
One of the things that has kept me back from recapping my 2250 is my lack of knowledge of "good" versus "bad" cap suppliers. I understand Blackgate was good, but they went under. I'm always wary of parts suppliers, since it is hard to determine quality from a picture or description, although the most telling thing for me is place of manufacture. I would be more keen to buy Japanese caps or USA caps over China caps, but that's just me. My 2250 doesn't have all too many electrolytic caps, and with the modular boards and a service manual, I would feel comfortable doing it on my own sometime.
Click to expand...

I have recapped the power board, filters, amp boards, and phono preamp in my 2250b, as well as a 2250b belonging to a good friend. If you want specifics about what I used for them, as well as my 2275's, etc., shoot me a message. That one definately has more 'lytics in the amps than a 2275 does, thats for sure!
 
sssmokin99 said:
I have recapped the power board, filters, amp boards, and phono preamp in my 2250b, as well as a 2250b belonging to a good friend. If you want specifics about what I used for them, as well as my 2275's, etc., shoot me a message. That one definately has more 'lytics in the amps than a 2275 does, thats for sure!
Click to expand...

Wow, that was an old post on my part! Since then I have recapped my 2250 with all Nichicon caps (Muse where available), so I'm pretty well versed in recapping now. :D Dang, how time flies.
 
MisterFishey said:
Wow, that was an old post on my part! Since then I have recapped my 2250 with all Nichicon caps (Muse where available), so I'm pretty well versed in recapping now. :D Dang, how time flies.
Click to expand...

I didn't even notice how old the thread was! :D LOL You are so right about that time in flight thing...!!
 
MikeED said:
JSTANG made a comment, "you can add a .1uF bypass to the mains and that help hi feqs." Would someone elaborate on this comment and specifically explain where on the 2270 PS, this bypass capacitor would be installed?

If it helps the high freq's, then a 20 cent part makes this mod an exceptional value. Appreciate any comments. Mike
Click to expand...

Place the 0.1uF cap across each main power supply filter cap, the big ones. It helps to shunt high-frequency noise that's riding on the rectified DC voltage to ground rather than send it out onto your power rails.
 
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