refoaming "Classic" AR9

[Guest]

Hello,

I have a pair of AR9 "classics" from ~1980.

Many of the drivers are in need of refoaming,

and the tweeters are not original, (nor are they

AR brand) I'm in search of either how to refoam

them myself, or the name of a reputable repair operation.

(in my part of the country, southwest Ohio)

Also, I'm looking for original tweeters, or ideas

on upgrading them. Any other "refurbishment"

ideas for these dynamos is most welcome.

Thanks!

John Timmel

Cincinnati, Ohio

[Guest]

Hi John;

Please see my replies to the AR90 question a couple notes down.

I have a pair of classic AR9 speakers, they are fantastic !

What are you using/planning to use for an amplifier? I currently using an Onkyo TX8500 (ca. 1977) receiver, good for around 150W into 4ohms. The system is in a room that is really far too small.

Nigel

[Guest]

Hi John,

>Hello,

>I have a pair of AR9 "classics" from ~1980.

>Many of the drivers are in need of refoaming,

>and the tweeters are not original, (nor are they

>AR brand) I'm in search of either how to refoam

>them myself, or the name of a reputable repair operation.

Refoaming yourself isn't that hard at all if you have any kind of aptitude for "handyman stuff" and get the proper tools (Exact-o knives and a couple of wood chisels). To see a good tutorial on the process, check out the photo spread here: http://www.decware.com/surround.htm.

If you think you can do all this, you can certainly refoam yourself. Step 10 is by far the most critical and the place you can get yourself in the most trouble. I, personally, have done several pairs of AR speakers and found the process a non-issue. On a personal note, if one of these replacement surround companies tells you that it's possible to refoam without shimming, IMHO that's a bunch of bunk. Spend the extra $5 and replace the dust caps and do it right (and the safest).

>(in my part of the country, southwest Ohio)

>Also, I'm looking for original tweeters, or ideas

>on upgrading them. Any other "refurbishment"

>ideas for these dynamos is most welcome.

Replacement tweeters should be available at Layne Audio (http://www.speakersupply.com). They're in Nashville. As far as repair shops in OH, I don't know...if you're close enough to Cincy I gotta think there'd be someone reputable.

>Thanks!

No problem, that's what we're here for!

Keith

[Guest]

Thanks!

I am using a Hafler DH-220 amp with excellent results.

I did blow the tweeters years ago, and replaced them

with non AR tweeters. (They sound good, but then again,

without doing an A/B comparison it is tough to tell)

Anyway, dry rot in the low midrange and woofers.

I'm looking forward to getting their original sound back!!

The room they are currently in is 15'x20', an 8' ceiling, hardwood floor, with a large area rug, upholstered and non upholstered furniture. (pretty reflective)

John

[Guest]

Hi John;

After you get your drivers re-foamed, you may want to consider increasing your amplifier power. Based on your room size, and blown tweeters, there is a probablitiy that your amp is going into clipping a significant amount time.

A second DH-220 would make a world of difference. See your AR9 manual for comments on bi-amping (or the one on this site). AR specifically recommends against using a crossover in front of the amplifiers. So all you need is the second amp and a couple of RCA Y cables. There is alot to be said for "vertical" bi-amping, that using one stereo amp for each speaker.

Nigel

[Guest]

Thanks Guys.

I was much younger and played music much much louder 15-20 years ago. Didn't the next version,(I think the AR90s) use magnetic fluid for the tweeters for cooling purposes?

Anyway, the Hafler DH220 is a great amp. Clean and lots of headroom, and has never given me problems in 20 years!!

Another option (besides splitting the woofers from the rest of the speakers on the AR9) with the Haflers is they can be Bridged.

I'll be watching for a reasonable price on another amp. Any suggestions when amping only the woofers?

I ordered the tweeters from Layne Audio and

the refoaming kit from another place that he suggested. The fellow at Layne's (don't have his name with me at this time) was

very informative, as was the on line "how to refoam" at decware.com

He brought up a few points.

1) You do not want to use a water based glue that is included with some refoaming kits. I think the drying time was the reason for this.

2) He suggested cutting off the dust cover and reusing it if not damaged, (could affect voice coil cooling, material for ventilation, etc) and shimming the coil. It makes total sense to me to imobilize the coil while everything dries.

3) Use of car headliner material for the missing thin "foam" around the upper midrange. (this is NOT the acoustic blanket)

4) Take a peak at the Crossover and think about replacing the caps.

The fellow I ordered the refoaming kit from said the kit did not include shims to immobilize the coil. When I questioned him, he gave some other technique. Anyone familiar with what he might be talking about? I'll find out soon enough, but will likely use shims.

The decware.com gives instructions to "renew" the cone with a watered down glue to help them break in quicker and protect them.

I wonder about this.

Anyway, I'll start with the 8" mids before tackling the woofers.

If I muck them up, I can replace/upgrade them relatively cheaply

with the poly cone types from AR.

Again, Thanks!!

I'll keep you all posted on my progress.

.

[Guest]

>He brought up a few points.

>1) You do not want to use a water based glue that is

>included with some refoaming kits. I think the drying

>time was the reason for this.

Too long or too short?

If you are shimming the voice coils then a long drying time is irrelevant. The people who want fast drying adhesives are those who aren't shimming so that once they get everything "aligned", it doesn't have a chance to shift on them. A water-based adhesive on a paper cone would be a good thing I would think. There'd be slight expansion of the pulp and capillary action of the glue into the paper for a better bond. That would be a good thing in my estimation.

>2) He suggested cutting off the dust cover and reusing

>it if not damaged, (could affect voice coil cooling,

> material for ventilation, etc) and shimming the coil.

> It makes total sense to me to imobilize the coil while

> everything dries.

That's fine but be aware there will be a visible glue line where it was cut. Also, most of the felt caps don't cut clean at all, even with a new x-acto blade...they're very fibrous. That makes it hard to get them glued back on nicely. Unless the cap is made of screen, any pressed felt cap *should* do. Though I wouldn't use poly caps if the originals weren't. To me, shimming the coil is the single most important thing to do, aside from not cutting the lead wires or the cone :-)

>3) Use of car headliner material for the missing thin "foam"

>around the upper midrange. (this is NOT the acoustic blanket)

Interesting idea, let us know if you find a source.

> The fellow I ordered the refoaming kit from said the kit

> did not include shims to immobilize the coil. When I

> questioned him, he gave some other technique. Anyone

> familiar with what he might be talking about? I'll find out

>soon enough, but will likely use shims.

Basically, they get at all glued up and just "mush" it around until it doesn't seem to rub anywhere...I wonder how that is really possible. Also, manila folder material seems to be a good shim thickness for most drivers.

>The decware.com gives instructions to "renew" the cone with

>a watered down glue to help them break in quicker and protect

>them. I wonder about this.

I did it on my 38s and 48s woofers...worked fine, or at least, didn't seem to be a detriment. The cones did look newer when done and I have to think they are protected more from humidity as they say. I think it was worthwhile.

>Again, Thanks!!

>I'll keep you all posted on

>my progress.

Please do, we like hearing it!

Keith

[Guest]

Re amp for the woofers. I would suggest you get another DH220. In the AR9 manual, AR suggested using the same amp for both. DH220s show up on ebay every so often, and at other used audio places, like:

http://www.audioclassics.com/

http://www.audioreview.com/market/

DH220 on ebay:

http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?V...item=1286362426

and there are several DH200s.

Have fun.

Nigel

[Guest]

Hello John,

I also own AR9's, basically have the same questions you do, own the same amp (Hafler 220) and live very near you in Northern KY. What a coincidence!

Like you I need to get them back up to speed. I'm very interested to find out if you're having luck refoaming these. I can be reached at: ukwebfan@yahoo.com and will be checking this thread often.

Please let me know.

Thanks,

Randy Glenn

[Guest]

Everything went very well and they sound great once again!!

Thanks for the help everyone!!

It is comparable to having bad eye sight, and not

realizing it until getting glasses. Holy COW!

From my new found experience:

Visit the web site earlier in this note. They do a good job

explaining things. The big difference on my job and theirs

was the glue type I used.

Use a couple good new xacto knife blades, one straight, and

another curved (a bit like a spoon)

You'll only need to do the lower midrange and woofers.

Start with the lower mids, because if you mess them up,

they're cheaper to replace, and the replacements are

apparently much better quality.

The type of glue I used was not water based, and dried very quickly.

NOTE:

This makes CENTERING the foam on the first try

very important!!

also

I don't think that attempting to refoam them

without using shims (I used business cards cut up,

these worked perfectly) would be a very good idea, especially

when using a quicker drying glue.

Either way, I'd spend the time to carefully remove the dust caps and put shims between the bobin and voice coil while doing the job. I do recommend the quicker drying glue, It was easy to get a goodbond quickly, without having the hassle of the foam detaching from the cone or the frame while it dried.

No ripples, and a very good quick bond!

I can post where I got my refoaming "kit" later...it was

recommended to me by the fellow at Layne Audio because of their use of the "correct" material and getting you the correct size foam.

The most difficult part for me was doing a good job of removing the dust cap(s) for reuse (I reused mine) without making an ugly mess of them.

Were I to do this again, I'd get new "outer" dust covers for the

lower midranges instead of reusing them. (purely cosmetic)

Note: On the lower midrange,

the outer "dust cap" covers up the real dust cover. The real dust cover

was a thicker piece of flat cardboard like material that was actually

easy to remove and glue back in place when done. Just make sure

to cut it out at an angle, so that it lays back in place easily.

Like so:

top

___________/ side

bottom

It was easier to remove and reuse the dust covers on the woofers because of their shape and they were a bit stiffer, but it took some care.

I also put back in new AR replacement tweeters (they seem to be better quality than the originals)

When I blew out the old ones in my younger days, I put in some

ribbon tweeters (relatively inexpensive from Radio Shack a long time ago)

I'm not sure that the ribbon tweeters didn't sound better, a bit more "airy".

I may do some comparisons with them back in, but for now,

the AR tweeters stay.

Bye now!

:-) :-) :-) :-) :-) :-)

[Guest]

Hi John, consider that you have the foam. 1. Clean the old foam and glue off the spkr. 2. Apply glue to both sides of the parts to be glued,the metal rim and the foam. Then the foam and the cone.(I used silicone,don't use rubber cement because it might melt the foam). 3. Getting to be a little tricky here but not difficult. Before you apply the foam to the metal rim use a heavy glass (cup)to weight down the cone so that the cone is kept away from the foam while you are gluing it onto the rim. 4. When you have glued the foam to the metal rim, slowly remove the glass from the centre of the cone, then carefully turn the whole spkr over onto the table and allow the cone to centre itself to the foam. You might have to give the cone a very slow and careful push downwards towards the foam. 5. Turn the spkr over, and use your fingers to squeeze tight the joint. Bingo! You got your AR repaired. I did six spkrs and only missed one. The cost of the foam was $3 Canadian each. Best wishes, Ron.

[Guest David in MA]

>Note: On the lower midrange,

>the outer "dust cap" covers up the real dust cover. The real

>dust cover

>was a thicker piece of flat cardboard like material that was

>actually

>easy to remove and glue back in place when done. Just make

>sure

>to cut it out at an angle, so that it lays back in place

>easily.

>

>Like so:

> top

>

>___________/ side

>

>

> bottom

>

Just wanted to mention that this note was a life-saver. I cut away the dust cap of the midrange on my AR9 and there was another dust cap. I wasn't sure what to do until I read this note.

Thanks.