Where to buy AR-9 Surround parts?

[Guest David in MA]

Hello all,

I am firsttime poster but I've been associated with this forum for a very longtime (I wrote the forum software, lol...). I actually never owned a decent pair of speakers so I didn't really read much, though. That changed couple of days of ago when my co-worker gave me his pair of AR-9's, which made his wife very happy (to get rid of it) and made my wife very unhappy ("they are too big!", she says)...so, here I am.

Anyways, although only one of the woofers show noticeble tear, these speakers do require reforming. I've been researching here and online where to get AR-9 surround parts. Could you please recommend? If possible, I'd like to hire someone to do it (within reasonable budget) if you're around Boston MA...

Thanks and I'll be waiting to hear from you.

David in MA

[ar_pro]

David -

Bill from Millersound in Lansdale, PA (215-412-7700) has refoamed several AR-9 woofers and 8" mids for me over the years. His work is absolutely first-rate, and his prices are excellent. He's also an expert on the AR-9, so you might just want to call and chat with him.

[Guest David in MA]

>David -

>Bill from Millersound in Lansdale, PA (215-412-7700) has

>refoamed several AR-9 woofers and 8" mids for me over the

>years. His work is absolutely first-rate, and his prices are

>excellent. He's also an expert on the AR-9, so you might just

>want to call and chat with him.

Thanks for your suggestion. I've read about Bill and I'm sure he is very very good. My only wish is that he was near where I am (Boston MA). I will give him a call and speak to him and see what sort of arrangement can be made...

Thanks.

[Pete B]

Hi David,

I was just wondering if you know the history behind these speakers or if you've listened to them as is. You might have noticed that we talk a lot about crossover capacitors here and noticed that electrolytics do not age well. There are many electrolytics in the 9s and if they've become leaky (many do) they could damage the hard to replace upper mid and tweeter drivers:

http://www.classicspeakerpages.net/dc/dcbo..._id=7195&page=3

http://www.classicspeakerpages.net/dc/dcbo..._id=7361&page=3

It would be good to determine if there is any serious damage other than needing edge replacement to any of the drivers. Do any of the woofers have voice coil or spider problems?

The cost of restoration will depend on these factors. I'd also plan on replacing all the smaller electrolytic caps with good quality low cost polys.

I'm interested in the 9s just because they're a legendary design.

Pete B.

>Hello all,

>

>I am firsttime poster but I've been associated with this forum

>for a very longtime (I wrote the forum software, lol...). I

>actually never owned a decent pair of speakers so I didn't

>really read much, though. That changed couple of days of ago

>when my co-worker gave me his pair of AR-9's, which made his

>wife very happy (to get rid of it) and made my wife very

>unhappy ("they are too big!", she says)...so, here I am.

>

>Anyways, although only one of the woofers show noticeble tear,

>these speakers do require reforming. I've been researching

>here and online where to get AR-9 surround parts. Could you

>please recommend? If possible, I'd like to hire someone to do

>it (within reasonable budget) if you're around Boston MA...

>

>Thanks and I'll be waiting to hear from you.

>

>David in MA

[soundminded]

>I'm interested in the 9s just because they're a legendary

>design.

Had any further thoughts/made any progress on designing a version of AR9 using currently available drivers?

[johnieo]

>good quality low cost polys.

It is my experience that the phrase when used to characterize polyproplyene capacitors, is an oxymoron. The quality of a finished pp capacitor depends on the crystalline structure of the starting film, as well as methods and other materials used to complete their construction. Personally, I consider of order a dollar a microfarad (say, ten microfarad size) to be good quality, but certainly do not consider that to be low cost.

[Pete B]

From what I've seen of your writing your comments about the sound of caps are the result of uncontrolled non A/B type tests and therefore your conclusions are unreliable. I've done the controlled experiment myself and offered a link to another group who's beliefs were changed by a similar experiment.

I'm not going to get into it with you, you have your beliefs, be careful when you make suggestions on a public forum. If your thinking of questioning my background please read my resume before jumping to conclusions. It is interesting that you will never see a boutique cap in precision instrumentation equipment from any of the reputable electronics companies. Certainly if they were better, improved performance could be obtained in precision analog instumentation gear. Nor will you find them in radar, computer, or any other non consumer electronics gear.

Here's an excellent quality poly cap at much less than a dollar a uF from a top manufacturing company:

http://madisound.com/gecaps.html

Often small boutique companies cannot afford the best manufacturing equipment that the billion dollar companies use, something to think about.

But again I seriously don't want to get into it.

Pete B.

>>good quality low cost polys.

>

>

>It is my experience that the phrase

>when used to characterize polyproplyene capacitors, is an

>oxymoron. The quality of a finished pp capacitor depends on

>the crystalline structure of the starting film, as well as

>methods and other materials used to complete their

>construction. Personally, I consider of order a dollar a

>microfarad (say, ten microfarad size) to be good quality, but

>certainly do not consider that to be low cost.

[soundminded]

>>good quality low cost polys.

>

>

>It is my experience that the phrase

>when used to characterize polyproplyene capacitors, is an

>oxymoron. The quality of a finished pp capacitor depends on

>the crystalline structure of the starting film, as well as

>methods and other materials used to complete their

>construction. Personally, I consider of order a dollar a

>microfarad (say, ten microfarad size) to be good quality, but

>certainly do not consider that to be low cost.

It seems to me plastics like polypropylene don't have a crystaline structure, by definition they are amorphous. What's more, plastics are made in vast batch quantities and the resulting economy of scale makes most of them very cheap. This includes polypropylene films. The technology for making this type of plastic is at least 40 years old. This is not rocket science. BTW, I agree with PeteB, there are no special expensive audiophile type capacitors used in even the most expensive and demanding laboratory electronic equipment I have seen. I've installed every conceivable kind of electronic equipment including some with very exotic and difficult requriements and nowhere in any of them have I ever seen the kind of absurd nonsense like special wires audiophiles routinely fall sucker to

[johnieo]

>It seems to me plastics like polypropylene don't have a

>crystaline structure, by definition they are amorphous.

Polypropylene can be fabricated in several forms. One of my experienced colleagues in our Materials Science Department explained that isotactic polypropylene is about 90% crystalline. The polymer molecules are much longer than the crystal diameter, which is always small, like microns--maybe up to a millimeter. The crystals are ordered regions where the parts of some polymer molecules line up. One polymer can fold on itself to form part of a crystal, and one molecule can also be in more than one crystallite at the same time. The intercrystalline regions, which constitute about 10% of the volume, are an amorphous tangle of polymer chains. Things can move around in polymers at room temperature, mostly in the regions between the grains. However, they do not exhibit grain-boundaries in the metallic sense. Variations in polymer quality, Al physical vapor deposition rate, and end connection techniques are some of the variables that distinguish quiet versus noisy capacitors that many of us on this Form have heard when using inexpensive pp caps in mid- and hi-range drivers. What I would call an exotic capacitor (Sn foil electrodes instead of deposited metal film electrodes) would undoubtedly be impossible to distinguish from a quality deposited-metal pp cap.

[soundminded]

>Variations in polymer

>quality, Al physical vapor deposition rate, and end connection

>techniques are some of the variables that distinguish quiet

>versus noisy capacitors that many of us on this Form have

>heard when using inexpensive pp caps in mid- and hi-range

>drivers. What I would call an exotic capacitor (Sn foil

>electrodes instead of deposited metal film electrodes) would

>undoubtedly be impossible to distinguish from a quality

>deposited-metal pp cap.

It seems to me that the "noise" in a capacitor might be significant in the front end stages of a very high gain amplifier, possibly one designed to be used at rf frequencies. Given the level of signal for loudspeakers, I'd expect the "noise" to be orders of magnitude lower in what you'd get out of any capacitor than would be audible. Do you have any data to support your contention of audible differences such as DBT results? How would you measure it on a test bench, DC leakage or non linear distortion increases? I'm sure the big manufacturers like CRC and Mallory would have a lot to say about it (I confess I am not much of a maven on capacitor performance) but I would take anything coming from small manufacturers who cater to audiophiles as pure baloney unless they have scientific tests to back up their claims.

[Guest Bret]

>I'm sure the big manufacturers like CRC and Mallory would have a lot to say about it (I confess I am not much of a maven on capacitor performance) but I would take anything coming from small manufacturers who cater to audiophiles as pure baloney unless they have scientific tests to back up their claims.<

The easiest way for you to come to terms with this is to try it. You don't need to be double-blinded, you don't need to measure it, and you don't even need to define it. "It" becomes obvious, whatever "it" is attributable to.

What you need is a good few good Solen capacitors, a few good North Creek capacitors, a speaker to mount each in, a little solder, a few hours (possibly much, much less) to listen, a willingness to hear, and then a fork, knife, and one very large appetite for crow.

Bret

[soundminded]

Bret;

Why should I waste my time and money repeating the capacitor DBT experiment PeteB cited?

"it seems like the switch isn't even hooked up."

"The bottom line on the whole day was that nobody did better than flipping a coin."

If I spent my life debunking every scam foisted off on audiophiles designed to steal their money, to my own satisfaction, I would have little room left for anything else. I'll sit up and take notice when someone comes up with something a lot more convincing than a litany of testimonials for snake oil. How about some THD or IM measurements?

BTW, I don't have to eat crow, I've saved enough money on not buying audiophile nonsense to eat fillet mignon every night if I want it.

[Guest David in MA]

I read all the messages in this thread w/ much interest since I started this thread. Thank you all for your comments.

I'm sort of confused now. When I read PeteB's comments, I should definitely replace the caps. Should I? What would happen if I don't? I was sort of hoping to just reform the surrounds and have it running for next 20 years...

Thanks again for a great discussion.

[Guest David in MA]

Hi Pete,

>I was just wondering if you know the history behind these

>speakers or if you've listened to them as is.

I just got them. They are my first "real" speakers.

> You might have

>noticed that we talk a lot about crossover capacitors here and

>noticed that electrolytics do not age well. There are many

>electrolytics in the 9s and if they've become leaky (many do)

>they could damage the hard to replace upper mid and tweeter

>drivers:

I see. So I guess I should take a look at the circuits and examine them for any signs of leakage. What should I look for?

>It would be good to determine if there is any serious damage

>other than needing edge replacement to any of the drivers. Do

>any of the woofers have voice coil or spider problems?

>The cost of restoration will depend on these factors. I'd

>also plan on replacing all the smaller electrolytic caps with

>good quality low cost polys.

What do I need to do this? Just soldering tool? Is this something simple to do myself?

Thanks for you input.

[soundminded]

>I read all the messages in this thread w/ much interest since

>I started this thread. Thank you all for your comments.

>

>I'm sort of confused now. When I read PeteB's comments, I

>should definitely replace the caps. Should I? What would

>happen if I don't? I was sort of hoping to just reform the

>surrounds and have it running for next 20 years...

>

>Thanks again for a great discussion.

It has been widely and correctly reported that electrolytic capacitors change value over time due to an almost inevitable chemical reaction which affects the dielectric. The capacitors of concern are specifically those in the crossover network. If they increase in value which is very possible, those in series with midranges and tweeters will allow lower than intended frequencies to reach the drivers increasing the likelihood of damage. Any change to any of them will also affect the sound. I've made my position on the value of expensive audiophile capacitors clear and I won't say anymore about it except that some audiophiles hold that using very expensive polypropylene capacitors makes everything sound clearer. One thing that's true is over a very long timespan, polypro caps will not likely change much in value, certainly not nearly to the extent of electrolytics so if you go to the trouble of changing them out, polys are definitely worth considering. If I had to change mine now, I'd probably use cheap polys. Do yours need to be changed now? The truth is that the only way to really know for sure is to remove them and check them with a capacitance meter to see if they have drifted from their original values significantly. BTW, I have a 21 year old pair of AR9s and I have no immediate intention of changing their capacitors. So far, only one lower midrange shows slight signs of foam deterioration and it hasn't affected the sound...yet. My motto, don't fix it if it ain't broke. (I've got enough problems in life with things that really are already broken to look for trouble where there isn't any.)

[Pete B]

Hi David,

You could try to test each component but generally electrolytic caps are only good for 10 to 20 years when not in continuous use or highly stressed. The leakage can actually be venting out of the cap, but it is also electrical when the oxide insulation layer breaks down. This can be seen when reforming the cap where the voltage rises very slowly as the oxide layer reforms. The safest thing is to just not take the risk of having one go bad down the road and replace them all on the mid and tweeter circuits. If I were in your shoes, I'd replace all the caps up to 100 uF.

The others are very large computer grade caps and are on the woofer circuit. There's a 2500 uF and a 470 uF if I remember correctly and they're computer grade caps which are higher quality and rather expensive. I'm not certain if you can even get these or a comparable replacement anymore.

We can discuss some solutions but first let me ask do you have any test equipment, DVM, signal generator, AC volt meter? Bench power supply?

Pete B.

>Hi Pete,

>

>>I was just wondering if you know the history behind these

>>speakers or if you've listened to them as is.

>

>I just got them. They are my first "real" speakers.

>

>> You might have

>>noticed that we talk a lot about crossover capacitors here

>and

>>noticed that electrolytics do not age well. There are many

>>electrolytics in the 9s and if they've become leaky (many

>do)

>>they could damage the hard to replace upper mid and tweeter

>>drivers:

>

>I see. So I guess I should take a look at the circuits and

>examine them for any signs of leakage. What should I look

>for?

>

>>It would be good to determine if there is any serious damage

>>other than needing edge replacement to any of the drivers.

>Do

>>any of the woofers have voice coil or spider problems?

>>The cost of restoration will depend on these factors. I'd

>>also plan on replacing all the smaller electrolytic caps

>with

>>good quality low cost polys.

>

>What do I need to do this? Just soldering tool? Is this

>something simple to do myself?

>

>Thanks for you input.

>

>

>

>

[Guest Bret]

>If I spent my life debunking every scam foisted off on audiophiles designed to steal their money, to my own satisfaction, I would have little room left for anything else.<

Nobody is asking you to spend your life or a lot of money being "The Amazing Randy" to golden-eared audiophiles.

Just try the North Creeks. They aren't even expensive as "audiophile" capacitors go.

Bret

[Pete B]

I should have mentioned to replace the electrolytics with a good quality film cap of equal value, 100V rating or more, try for 5% tolerance, 10% will do and is what the stock caps were. The GEs that I mentioned, Solens, Bennics, or mylar caps would be fine assuming you want to keep the cost down. The difference in cost between mylars and Solens is not that great so I usually go with Solens. Some suggest high end caps but we should keep in mind that the original parts were electrolytics.

The inductors should be fine, you could measure their DC resistance if you wanted to be extra cautious.

It would be wise to measure the resistors since their value can drift when excessive power is applied and replace as necessary.

It's suggested that you clean and reflow all the solder joints just in case any are aging or were cold joints from the factory.

Pete B.

[Guest Bret]

>When I read PeteB's comments, I should definitely replace the caps. Should I?<

Yes.

>What would happen if I don't?<

The speaker will not sound good due to peaks, overlap, or dead areas in the crossover - that's at best - and you could blow some difficult and expensive to replace drivers at worst.

>I was sort of hoping to just reform the surrounds and have it running for next 20 years...<

Yeah, well. . . "best laid plans" and all that stuff. Doing only a refoam-job may be possible with some older or newer models, but probably not with speakers of this era. The capacitors in these seem prone to failure.

On the bright side, you can be sure that the time, money, and effort you put-in now will be rewarded far into the future. For all its faults, a properly playing AR-9 is a majestic thing.

Bret

[Guest Bret]

>It would be wise to measure the resistors since their value can drift when excessive power is applied and replace as necessary<

Considering the low cost and light labor involved, would you recommend he just go-ahead and use a new low-inductance 1% resistor?

I would. It's easier than worrying with the old one which we know is improperly mounted.

Bret

[Guest David in MA]

>It has been widely and correctly reported that electrolytic

>capacitors change value over time due to an almost inevitable

>chemical reaction which affects the dielectric. The

>capacitors of concern are specifically those in the crossover

>network. If they increase in value which is very possible,

>those in series with midranges and tweeters will allow lower

>than intended frequencies to reach the drivers increasing the

>likelihood of damage.

Is this true even at low volumn where the power applied to the driver is small?

> Any change to any of them will also

>affect the sound.

Ok.

> Do yours need to be changed now?

I don't know. The speakers sound fantastic even w/ my cheap JVC receiver.

> So far, only one lower midrange

>shows slight signs of foam deterioration and it hasn't

>affected the sound...yet.

One of the woofer shows form deterloration. But you could tell I need to replace all of them (4 woodfer + 2 midrange) sometime in the near future.

> My motto, don't fix it if it ain't

>broke. (I've got enough problems in life with things that

>really are already broken to look for trouble where there

>isn't any.)

Good point. Am I correct to believe that the speakers will degrade gracefully over time?

Thanks again.

[Guest David in MA]

>

>>What would happen if I don't?<

>

>The speaker will not sound good due to peaks, overlap, or dead

>areas in the crossover - that's at best - and you could blow

>some difficult and expensive to replace drivers at worst.

I see. At some point I'll have to do this. Is the driver damage only at high volumn or at any power level?

>On the bright side, you can be sure that the time, money, and

>effort you put-in now will be rewarded far into the future.

>For all its faults, a properly playing AR-9 is a majestic

>thing.

I agree...I'm in heaven...

[Guest David in MA]

>You could try to test each component but generally

>electrolytic caps are only good for 10 to 20 years when not in

>continuous use or highly stressed. The leakage can actually

>be venting out of the cap, but it is also electrical when the

>oxide insulation layer breaks down. This can be seen when

>reforming the cap where the voltage rises very slowly as the

>oxide layer reforms. The safest thing is to just not take the

>risk of having one go bad down the road and replace them all

>on the mid and tweeter circuits. If I were in your shoes, I'd

>replace all the caps up to 100 uF.

Thanks for the information. I will most certainly do this sometime near future. I will most likely need to hire someone to do this?

>We can discuss some solutions but first let me ask do you have

>any test equipment, DVM, signal generator, AC volt meter?

>Bench power supply?

Nothing. I have no such equiptment. I'm just a casual music listener who was lucky enough to have a friend who's wife doesn't like big entertainment systems (form over function, I guess)...

Thanks for your thoughtful comments.

[Guest Bret]

>I see. At some point I'll have to do this. Is the driver damage only at high volumn or at any power level?<

I suppose it's possible at any power level. . . I wouldn't think likely. But "power level" can mean a lot of things. . . including "attempted power level." It's an involved discussion and you don't really need to get into that right now, if I understand your intentions. Just realize that the tweeter is built to tweet in specific frequency ranges and that playing bass through it will destroy it. A faulty crossover puts "bass" (okay, so midrange) through the tweeter.

It'd be a little like using the trunk of your car to carry the load meant for a dump-truck. Something's going to give.

There are several people here who have "been there / done that" with a pair of AR-9s. MY take, having done it piece-meal myself, is that the whole experience can be made much better and less painful by only doing it once.

All you need are wire cutters, a soldering iron, solder, either hot-melt (be careful) or silicone adhesive (still be careful), the new capacitors of the correct values, and an afternoon. You can break it up into multi-part steps, but there's no need, really. This is a fairly primitive operation and does not require outstanding electronics skills. If you can solder, at all, you can do this.

If you choose not to do it all right now, in my opinion, for your own good and safety and enjoyment and peace of mind, you should replace all of the capacitors 80uF and smaller. (I'd opt for all of them except the 2500uF, myself.)

Removing these and testing them is an unnecessary step in the process. Oh, it's interesting and all that, but ultimately it's academic. The caps are very old. They may be damaged. New ones won't be old or damaged. Don't sweat it, just replace them. (this coming from a guy that agonized for months about every detail - it was a waste of time and effort)

You do not have, nor are you likely to have access to, a capacitor tester that can do a competent broadband job and test for all possible modes of failure. I bought an "average" cap tester and found it to be of little value. You need a really good one. Such devices are extremely expensive. The time and cost of doing all that running-around, buying gear, and paying for tests greatly exceeds the cost of just replacing the caps and being done with it, then living happily ever after knowing that the crossover is in spec.

As you no-doubt have already read, I do have a favorite cap, but that's really another subject. What I'm most interested in is helping you get yours back to working "properly."

Bret

[Guest David in MA]

>All you need are wire cutters, a soldering iron, solder,

>either hot-melt (be careful) or silicone adhesive (still be

>careful), the new capacitors of the correct values, and an

>afternoon. You can break it up into multi-part steps, but

>there's no need, really. This is a fairly primitive operation

>and does not require outstanding electronics skills. If you

>can solder, at all, you can do this.

Got it. I guess I need to get a list of caps that I need to replace and do it all at once. Thank god for the archives in the library section. If you know a page that has a list of all caps I need to replace, that'd be great.

>If you choose not to do it all right now, in my opinion, for

>your own good and safety and enjoyment and peace of mind, you

>should replace all of the capacitors 80uF and smaller. (I'd

>opt for all of them except the 2500uF, myself.)

Ok.

>As you no-doubt have already read, I do have a favorite cap,

>but that's really another subject. What I'm most interested

>in is helping you get yours back to working "properly."

I'm sort of confused in this part. Should I go with high end caps or just some caps of proper capacitance from radio shock? Does it make any difference?