Questions about caps.

djf

OK, I have been investigating suppliers and part availabilty to rebuild xovers on my SRS's. I am also still anxiously awaiting tso more of the silks!

But I am not an electrical engineer and am curious.

First, I opened the box and examined the crossover closely. I noted the position, size, and part numbers on all the caps. I have:

2 TSI 8531 130mfd 75VPAC +/-20%
2 TSI 8539 20mfd 50VPAC +/-10%
1 TSI 8533 92mfd 75VPAC +/-10%
1 TI 4.4mfd J 100V
1 TI 12mfd J 100V

There is also a small brown relay/thermistor type part in the middle of the board which I am unsure of.
So...

Does the voltage make a difference? As long as I get a cap rated at the particular voltage or higher am I then alright?

Are these items polar? Do I have to hook them up +/- in some direction?

If I can't get a 130, can I parallel/serial say, a 50 and an 80 to add up to 130? Or should I strive to get a 130 even if it is of slightly lower quality?

These tolerance percentages seem quite loose to me. Is there a huge benefit to get much higher tolerance caps? 5%? Mil Spec?

Are the polyfilms truly that much better? Or would electrolytics with tighter specs be as good?

Is it, in general, better to stick with one supplier? Do they work better together if they are the same supplier? Or is it OK to mix and match?

I was asounded to see some of the prices. One site had some poly caps on sale, and the larger value ones were upwards of 100 bux each. Are these folks making these by hand? If there was a way to make them, I'd give it a try, except for the fact that it would be hard to control the capacitance and tolerances.

Any body have any ideas?
Thanks!

george daniel

When I rebuilt the x-overs in my 1c's, I used caps with with a higher voltage(in somes/most cases),Mills resistors,new polys,the spec's on the caps were much tighter,I used the solen "pb series",some prefer sonicaps,currently rebuilding x-overs in my brothers 2.3tl's,call Jeff (i believe) @ sonicraft and he can help you out,I have to give the credit for my success to Jesse(f-1),as he has e-mailed me the schematics,and parts list,which made things much easier. While you are in the neighborhood,you might as well change the binding posts. Prior to doing this I found alot of information using the "search" function.I'm sure that when others read this,they will chime in. Mine are really sounding great after about 50 hours or so "burn in". Hope this was of some benefit.

djf

Thanks! I consider this to be the learning/investigation/feasability/planning phase. I know many others here have done it, so it'd be nice to know the pitfalls before I blow up my amps or something!

F1nut

SDA SRS crossover parts list.

This is the total needed using Solen PB 400v caps at 5% tolerance or better.
(2) 4.4uF
(2) 12uF
(4) 20uF
(2) 92uF
(4) 130uF

Mills Wire-wound 5 watt (MRA-5) resistors, 1% tolerance.
(2) 2.7ohm
(2) 7.5ohm
(2) 15ohm
(4) 22.5ohm

Silver Mica caps 5% tolerance or better.
(4) 750pF

Polyswitch from Polk.
2 needed



One stop shopping, http://www.partsconnexion.com/partscomponents.php

djf

F1,
Thanks! I will take it under advisement. I have read alot of threads on upgrades and your name frequently shows up, so certainly you are experienced/knowledgeable about it.

I am still in the planning/learning phase, so I haven't made any decisions yet.

It sounds as though this might end up being more expensive than the silks.

It might keep me outa trouble for awhile. And I am still very interested to any other answers to my questions, because I love to tinker.

http://www.wimsbios.com/phpBB2/viewtopic.php?t=6368

djf

Allright! I think I have made a decision.

Sonicaps for the 4.3's, 12's, and 20's.
I will do Solen for the 91's, and defer the 130's until after I have done this work, then re-assess.

Does anyone know if the fact that there are 2 20's and 2 130's, if that has to do with the primary vs. SDA drivers? I am not trying to de-engineer anything, just curious.


Currently:
Mama where's yur pretty little girl tonite,
tryin to run before she can walk, that's right...

joeparaski

Can a customer just send his crossovers to Polk and have THEM rebuild or upgrade them??

george daniel

When I was rebuilding my x-overs, I recall Jesse advising me against mixing brands of caps(I think),as stated before, brand is up to you,,I used solen pb's--400 volt, current 2.3 x-over,will use sonicaps(my brother's pref),use the list,links, etc. that Jesse posted,and you can't go wrong,I recall getting most everything from partsconnexion,,if you need any solder,I have PLENTY

F1nut

djf, I would advise against using different brands of caps on the same crossover and there's no point in doing only part of the crossover. Either do it all or don't do it.


joeparaski, no.

djf

Update:

Received my third pair of Silk tweeters today and installed them. As it stands now, the top 3 tweeters on each unit are the silks, and the bottom is the original SL2000.

Heard some very high notes (well, depending on how old your ears are) on "The Wall".

Still totally committed to upgrading xovers, just not sure when or exactly what approach I will take!

Currently: Almond looks that chill divine...

Also fighting a virus on one of my W2K machines (the one I use for Napster) so I'm pixxed that it's probably gonna destroy all my licenses. Arrrghh!! Can't even be HONEST these days...

schwarcw

I like the Sonicaps. These are a personal preference. They cost more but Jeff at customer service a Soni Craft is a great source of information. Call or email him. He can also pull caps off the shelf and meausre them to get real close to the actual values you want. Also Sonicaps have longer leads, you may need them when mounting large caps on a small board. Go for the Mills MRA-5s. I also substituted a 0.1 uF capacitor for the 750 pF silver Mica. A lot of debate on this issue back in November on this Forum. I also junked the polyswitches and used a 14 guage insulated solid copper jumper. Some are uncomforatable doing this, others have done it without and problems. A lot depends on your equipment and your listening habits. If you play loud music often, with a small amp use the polycaps. Otherwise replace the with a copper jumper. I think they help give you better sonics.

Carl

dorokusai

If it wasn't for DarqueKnight's post about a crossover upgrade, none of this hoopla would exist. I don't recall much history via Polk regarding this at all. Does Polk use "generic" caps? Sure they do, what commercially viable company doesn't?

If you want to upgrade, rock on, it certainly can't hurt. Dahlquist had a capacitor upgrade suggestion for the DQ10 loudspeaker, and it's a 1970's speaker and simply due to a bad production run.

If you think it's a requirement? You just fell off the boat.

In regards to capacitors and individual brands of them, please, it's as hardcore as your wallet is.

A high quality cap is the same across the board, it just depends if you want to be cool or smart.

F1nut

dorokusai wrote:

A high quality cap is the same across the board, it just depends if you want to be cool or smart.

As this fella has more experience than you or I, I will defer to his knowledge that all high quality caps are not the same. http://home.versatel.nl/geenius/Cap.html

A nice (and long) article by Walter G. Jung and Richard Marsh,
http://www.capacitors.com/picking_capacitors/pickcap.htm

A Maggie crossover upgrade,
http://www.audience-av.com/magnepan_mg12_crossover_upgrade.htm

Crossover upgrades and capacitor upgrades in general have long been recognized as worthwhile endeavors.

djf

dorokusai wrote:

If it wasn't for DarqueKnight's post about a crossover upgrade, none of this hoopla would exist. I don't recall much history via Polk regarding this at all. Does Polk use "generic" caps? Sure they do, what commercially viable company doesn't?

Thanks! In fact it wasn't Dark's post. It was because I knew there were problems with my setup, I posted and asked questions, folks mentioned the polyswitches, and they fixed that problem.

dorokusai wrote:

If you think it's a requirement? You just fell off the boat.

These speakers are awesome. But they just turned twenty years old. F1 correctly pointed out the fact that caps (just as resistors do, but much moreso than resistors) do lose their operating characteristics.

And I have heard it myself. On occasion they act like it is taking a bit more to "warm them up" than other times. I think they are doing better and evening out because now at least I can give them decent power levels(>100WPC).

Personally, I think I can piecemeal replace parts. In my mind, that makes alot of sense, because of the learning curve about disassembly, etc. And I am a patient man.

No doubt, the best improvement one can make to the vintage units are the silks. I have been astounded, really, about how much more I hear. It is not just instrumental and frequency, there is a tactile change as well, hard to describe.

My questions on this thread are so I can learn as much about actually doing the upgrade as possible. How and why. And I need to know more about basic electronics. I don't know the difference between putting a cap in series versus in parallel.

I'm digital, not analog!

dorokusai

F1nut wrote:

As this fella has more experience than you or I, I will defer to his knowledge that all high quality caps are not the same. http://home.versatel.nl/geenius/Cap.html

A nice (and long) article by Walter G. Jung and Richard Marsh,
http://www.capacitors.com/picking_capacitors/pickcap.htm

A Maggie crossover upgrade,
http://www.audience-av.com/magnepan_mg12_crossover_upgrade.htm

Crossover upgrades and capacitor upgrades in general have long been recognized as worthwhile endeavors.

Richard Marsh? LOL The ex-Monster Cable power guru....sure, I read his words like **** juice. What an example Jesse.

Thanks for the other opinions, nothing factual as usual. I'm happy that you can justify your additional expense, it's your money, not mine. Your knowledge of capacitor upgrades and the perceived value of them started within the last couple years.

Please reference a thread by yourself, talking about replacing capacitors prior to DK's project. I wait on bended knee for this breaking story.

Here's some printed opinion, as in literature that can be handled, for your reading pleasure.

"Several writers have praised the technique of subtracting pulse signals through two different sorts of capacitor, claiming that non-zero residue proves that capacitors can introduce audible errors. My view is that these tests expose only well-known capacitor shortcomings such as dielectic absorption and series resistance, plus perhaps the vulnerability of the dielectic film in electrolytics to reverse biasing. No-one has yet shown how these relate to capacitor audibility in properly designed equipment." - D. Self, Audio Power Amplifier Design Handbook, 2002 Edition

I'll look up another comment when I have time to do so. Happy Listening!

dorokusai

djf wrote:

Thanks! In fact it wasn't Dark's post. It was because I knew there were problems with my setup, I posted and asked questions, folks mentioned the polyswitches, and they fixed that problem.



These speakers are awesome. But they just turned twenty years old. F1 correctly pointed out the fact that caps (just as resistors do, but much moreso than resistors) do lose their operating characteristics.

And I have heard it myself. On occasion they act like it is taking a bit more to "warm them up" than other times. I think they are doing better and evening out because now at least I can give them decent power levels(>100WPC).

Personally, I think I can piecemeal replace parts. In my mind, that makes alot of sense, because of the learning curve about disassembly, etc. And I am a patient man.

No doubt, the best improvement one can make to the vintage units are the silks. I have been astounded, really, about how much more I hear. It is not just instrumental and frequency, there is a tactile change as well, hard to describe.

My questions on this thread are so I can learn as much about actually doing the upgrade as possible. How and why. And I need to know more about basic electronics. I don't know the difference between putting a cap in series versus in parallel.

I'm digital, not analog!

It's opinion honcho, caps losing capacitance to the point of being audible, is a theory and if you subscribe then of course, you believe. Good luck in your travels.

F1nut

dorokusai wrote:

Richard Marsh? LOL The ex-Monster Cable power guru....sure, I read his words like **** juice. What an example Jesse.

From the article by Walter G. Jung and Richard Marsh.
"Acknowledgements
The authors would like to acknowledge private discussions with John Curl and J. Peter Moncrieff on the subject of capacitors in audio circuits and how they might influence subjective testing."

Hey, isn't that the same John Curl that you hold in such high regard? Why, yes is. :rolleyes:

What is your problem? A few years ago, you knew next to nothing about audio, so get off your high horse. You should know me well enough by now that I'm not going to say something if I haven't heard it for myself.

dorokusai

I've been into audio since 1985, don't tell ME about MY history. Is that like me saying you don't know a damn thing about tubes? We may have met a couple years ago, but that doesn't make you my freaking mentor.

High horse? You define high horse in this place you inflated ego Polkie.

Read the key word in that same quote you struggle to even grasp...."subjective". That says it all.

F1nut

dorokusai wrote:

Richard Marsh? LOL The ex-Monster Cable power guru....sure, I read his words like **** juice. What an example Jesse.

Now, that I have more time to respond, let's break this down.

Yes Mark, Richard Marsh. The same Marsh that designed your Monster Power Center that you must have thought enough about to purchase, yet at this point in time decide that his words hold no weight. Interesting.

Thanks for the other opinions, nothing factual as usual. I'm happy that you can justify your additional expense, it's your money, not mine. Your knowledge of capacitor upgrades and the perceived value of them started within the last couple years.

Please reference a thread by yourself, talking about replacing capacitors prior to DK's project. I wait on bended knee for this breaking story.

How does one differentiate between opinion and fact on a subject as subjective as audio? I'm not sure I have a good answer to that, but as some of the links I provided came from some fairly knowledgeable folks, I quess one could say they are facts. You are correct, it is my money or the money of the other people doing the upgrades. So, why do you feel the need to poo-poo how I or others spend our money? Nobody poo-pooed you when you bought the CTC amp that started life as a Parasound 3500. What was one of the many upgrades that was done in the process? They upgraded the capactiors!!!

Again, you are correct that I wasn't into capacitor upgrades until the last couple of years and that Raife, to the best of my knowledge, was the first person to post about them here. So what!?! Is it any different than someone who discovers the differences in tubes or cables? Nope, sure isn't. Why don't we try to figure out who was the first person to post on how cables make a difference? I can tell you it certainly wasn't me and it certainly wasn't you, yet we both know, first hand, what a difference they can make and we share that knowledge with others in the hope that they too might enjoy better audio because of it. That's what we do here, share our knowledge.

Here's some printed opinion, as in literature that can be handled, for your reading pleasure.

"Several writers have praised the technique of subtracting pulse signals through two different sorts of capacitor, claiming that non-zero residue proves that capacitors can introduce audible errors. My view is that these tests expose only well-known capacitor shortcomings such as dielectic absorption and series resistance, plus perhaps the vulnerability of the dielectic film in electrolytics to reverse biasing. No-one has yet shown how these relate to capacitor audibility in properly designed equipment." - D. Self, Audio Power Amplifier Design Handbook, 2002 Edition

I'll look up another comment when I have time to do so. Happy Listening!

Hey, that's great. The more info we share, the more informed we get.

I've been into audio since 1985, don't tell ME about MY history. Is that like me saying you don't know a damn thing about tubes? We may have met a couple years ago, but that doesn't make you my freaking mentor.

And I've been into audio since 1970 I have neither asked you to be nor stated or implied that I wanted to be your mentor. There is much to learn about audio and I'm still learning. If I ever get to the point that I know at all, I'll let you know.

High horse? You define high horse in this place you inflated ego Polkie.

Read the key word in that same quote you struggle to even grasp...."subjective". That says it all.

Again with the insults. I don't appreciate nor deserve them and find it rather unbecoming really, especially coming from someone who calls himself my friend.

dorokusai

Whatever, happy listening!

djf

I'm keepin my dog outa this one. But a quick Google gives this:

One of the biggest problems that aging units have are the electrolytic capacitors. A generally accepted life span for an electrolytic capacitor is approximately 15 years for consumer applications. There is plenty of variation here as heat will accelerate the aging process. One of the more pronounced effects of electrolytic capacitor aging is that they start to behave more like resistors rather than capacitors, and when they do finally fail they generally take a bunch of circuitry with them! Considering that this is a twenty year old unit with hard to find, if not impossible to find parts, the first step will be to replace ALL of the electrolytic capacitors. This may appear to be excessive for some folks, but good quality, high temp (Sprauge 517D series:105 C) electrolytic capacitors are not exactly expensive. My replacement cost was about forty dollars, including shipping, for the entire unit.

http://www.audioholics.com/showcase/DIY/YamahaT-80p1.html

nathanso

djf, That bit you pulled via google is right on. I just recapped a pair of AR90s and paused between speaker #1 and #2 to do an A/B test. In my listening room, an A/B test uses a Niles SPK-1 remotely actuated A/B switcher so I can be sitting in the sweet spot while I rapidly flip back and forth from A to B.

In this case I was running my pre-amp in mono, left channel into the re-capped AR90, right channel into the original capped speaker. My wife was sitting next to me for a second opinion.

It took all of 20-seconds and 3-4 switchovers to identify the re-capped speaker as sounding obviously better. It's bass was tighter, its vocals clearer, and overall smoothness better. The original speaker sounded hollow, as if it was playing through a short length of sewer pipe; its bass was loose and undefined.

All this improvement from $15 of caps from Madisound. I used cheap Bennic non-polarized electrolytics for the larger caps and Carli mylars for the smaller caps where the price for mylars was reasonable. I don't think resistors degrade enough to warrant replacement, and certainly not inductors.

scottyf

I don't think that we can measure everything that happens in stereo equipment. I know the modified Counterpoint equipment from Alta Vista literally transformed my listening experience....to a level I didn't even know existed! With capacitor and resistor upgrades, Mike Elliott dramatically improves in every way old Counterpoint equipment. At least to me and the other people I've let listen to my system.

Even the designers of Conrad Johnson equipment acknowledge differences in the sound of capacitors.
From the Stereophile reveiw of the CJ Act 2 preamplifier:

"Polypropylene caps have about [1%] the dielectric absorption of cheap capacitors. Polystyrene caps are two or three times better than that—and the Teflon parts we use in the ACT2 are fractionally better than polystyrene, although at a substantial increase in cost. The same is true with resistors—the off-the-shelf models used in mass-manufactured products cost fractions of a cent, whereas the Vishay resistors we use cost several dollars each. We use 24 in the volume control alone, and another 40 throughout the circuits. That adds up. But they're worth the price, because we haven't found anything that lets more of the signal pass through unaffected. And that translates into greater detail and more transparent sound."

madmax

Caps certainly can make a big difference. So whats big? That is the real question. If there is a small annoying irregularity that keeps bugging you and you remove it, that is BIG. If you remove an underlying gurgle in the backround, that is BIG. If you notice a change but can't point to anything in particular, well, thats not big.
madmax

nathanso

>>So whats big? That is the real question.

With my AR90's (and I'm guessing most 20-year old speakers with original caps), I think most people who listened without the benefit of a true A/B test would think the original caps sounded just fine; great, even. The A/B test, however, made it immediately apparent that there was significant clarity to be gained by re-capping.

One day I might try an NPE vs Exotic capacitor A/B test.. that would be truly interesting, though it has been done and nobody was able to do any better than a tossed coin: http://www.members.aol.com/pjay99site/captest2.htm

dorokusai

There is solid data for and against cap upgrades, it just depends on who you believe. You can't be subjective while performing a project on your own gear, that ability ended when you decided to do it. People don't often realize the power of their own brain to formulate preconceived thoughts and opinions.

The only way to know for sure, is to not know at all, and be told later that said equipment was upgraded or stock.

As to the Stereophile review excerpt, please find a bad review of anything from that magazine.

madmax

dorokusai wrote:

You can't be subjective while performing a project on your own gear

I disagree with that. I've made changes I knew would obviously sound better and was not able to prove it to myself. Ego driven people probably can't do it and people without testing experience can't do it. Just knowing doesn't necessarily mean anything.
madmax

F1nut

dorokusai wrote:

There is solid data for and against cap upgrades, it just depends on who you believe. You can't be subjective while performing a project on your own gear, that ability ended when you decided to do it. People don't often realize the power of their own brain to formulate preconceived thoughts and opinions.

The only way to know for sure, is to not know at all, and be told later that said equipment was upgraded or stock.

As to the Stereophile review excerpt, please find a bad review of anything from that magazine.

Whatever, happy listening!

schwarcw

Whatever works for your own ears is all that matters! Placebo effect? I'm sure it happens. I definitely heard a difference with the cap mod. Profound? Maybe for some ears, not mine. Worth the trouble and cost? Yes! I had a blast doing it and I saw an improvement in my sound quality! This is a hobby that you have to have fun with. If you take it too seriously, it's no longer fun.

I like the conversations on these Forums, there fun!

Carl

djf

schwarcw wrote:

Whatever works for your own ears is all that matters! Placebo effect? I'm sure it happens. I definitely heard a difference with the cap mod. Profound? Maybe for some ears, not mine. Worth the trouble and cost? Yes! I had a blast doing it and I saw an improvement in my sound quality! This is a hobby that you have to have fun with. If you take it too seriously, it's no longer fun.

I like the conversations on these Forums, there fun!

Absolutely. I have noticed a VAST improvement with the silks. And in fact I think getting better electronics might make more of an improvement than rebuilding the xovers.

But I am a very project oriented person. And I like trying new things, especially manual things where I disassemble-reassemble stuff.

And since I did my rototiller last year, I guess the SDA's are next!

djf

And for all the geeks and not-so-geeky out there, watch out for a new Trojan. Check your C: drive and if you find something called DRSMARTLOAD.EXE, you're in trouble.

I ended up having to FDISK my drive and do a complete reinstall of W2K.