Issues with AR9

[Guest]

I have two issues with trying to approximate the sound I had in the by-gone days of hifi heaven.

Issue #1:

I’m trying to be careful. I have a pair of AR9s I bought in late ‘78 or early ‘79. The tweeters were replaced after “The Infamous Drunk Roommate Finds the Tape Monitor Switch Incident of 1979.” My memory is that the original tweeters were not ferrofluid filled, but the replacements ordered later that same day were. These speakers were retired in 1993 when the baby arrived and the foam gave-up. They have been in climate-controlled storage since 1994.

I have spoken to Mr. Tidwell at Layne and have read everything I can here. There is no reason for me to doubt anything I have learned, but I’m reading things that are either contradictory or beyond my comprehension.

I believe it was Mr. Kantor, if not I apologize, who wrote that replacing the electrolytic capacitors with polypropylene or others might have the effect of changing the speaker system’s voice. Then I read with interest the article about refurbishing the AR94 reproduced from TNT Audio. And Layne is recommending that I replace the 8" AR driver with a polypropylene driver.

My concern is that anything I do to my 9s other than restore them exactly the way they were is going to change the speakers’ designed voice. I apologize to anyone whose toes I am stepping on, but I’m not sure I want my speakers to sound better. As I recall them, the 9LS model used polypropylene drivers and, well, I never thought they sounded as good as my plain-ol’ 9s. My best recollection is that the 9LSs had a very “up-front” sound compared to a, what?, mellow?, deep?, sound from the 9s.

I don’t have an audio signal generator at all, much less one that would produce a square wave, so trial and error combinations of caps is probably not in my future. Do I go back to electrolytic caps or upgrade? Do I use polypropylene drivers for the 8" or re-foam the originals?

Issue #2:

Since another time of infamy, “The Great Procreation Episodes of 1993-1994" and a semi-reprise in 1996, I have lost considerable clout in my own home. No longer am I free to stack electronics everywhere and run wires across doorways and fill multiple open-faced cabinets and light the room with LED displays and VU meters. Therefore, I have to ask a stupid question borne of a desire to avoid divorce court.

What receiver would anyone suggest, preferably not esoteric, preferably vintage, preferably not the size or weight of a Pioneer SX-1980? It has to “fit in the cabinet.” I know. . . Anathema. Stereo, no home theater. I like analog FM dials. I need current and obviously it would have to be low-impedance tolerant. The room is large (31' x 22') and the speakers have to be placed on the long wall. I don’t get to listen to Led Zeppelin IV at ear-bleed volumes anymore (while anyone’s home, anyhow) but Saint-Sean’s Symphony #3 can’t be listened to except at some volume. I used to like my Kenwood KR-9600 but have read unappealing things about them as they age. I might be able to fudge a pair of slim power-amps “hidden” here and there but pure separates are almost certainly out.

Thanks for any and all comments, suggestions, or inputs of any sort.

Bret

[ar_pro]

Bret, I believe that you're correct regarding the sound of the 9LS, which was to my ears, inferior in every way to the original Model 9. The plastic 8" driver was certainly an important factor in the voice of this design, and I'll bet that substituting it for your 9's original driver could be a mistake. I'm biased in favor of restoring vintage loudspeakers to original condition, without "improving" them, although I think that practical aspects of construction (like the replacement of friction-fit connections with soldered joints) definitely has a place. Also, I'm pretty sure that the 9 used ferro-fluid tweeters from the beginning (it's in the lit)...when I read about the delicate nature of the AR tweeter, or how easy they are to burn out, I have to wonder why I've never lost one! I'm going to chalk it up to amplifier power...LOTS of amplifier power. My speakers have always had plenty of clean juice available (a variety of models from McIntosh, Crown, & Adcom), and have never driven an amplifier into clipping or overload, resulting in (I believe) long-lived tweeters. If you check out some of the many posts, you'll find that Mac & Adcom (and Hafler & Dyna) are real favorites...very stable & reliable, and in the case of the Adcom 555II, a LOT of power for not too much money. I'll bet that you could latch onto an Adcom preamp (they made an excellent passive preamp that sells on ebay for about 100 bucks) & power amplifier that wouldn't take up much more space than those big Japanese receivers...it would be a great match for your classic speakers!

[Guest]

>inferior in every way to the original Model 9.<

Thanks for that comment. I didn't think I was imagining things.

>that substituting it for your 9's original driver could be a

mistake.<

That settles it. I guess all I needed was for someone to confirm I wasn't being too sentimental.

>I'm pretty sure that the 9 used ferro-fluid tweeters

from the beginning (it's in the lit)<

I understand. I don't *know* this, but I'm guessing mine were very early production models. I was selling audio equipment at the time and got a pair the rep for our area had at one of his accounts. They couldn't sell them so I bought them for 50% of retail on an employee-purchase plan. My memory could be playing tricks on me, but I'm almost certain that the ones I replaced were not ferro-fluid. Maybe they had been replaced with some out of 11s?

>delicate nature of the AR tweeter<

I agree with you. They really aren't delicate. These were lost to an idiocy. The roommate had the SX-1980 turned all the way up on FM, then flipped the tape monitor switch. It startled him badly enough (nearly brought the ceiling in) that he fumbled trying to find the volume control. So at a rated 270 watts driven nearly to DC for probably close to 15 seconds, they just couldn't take the heat. The crossovers seemed to have survived.

>LOTS of amplifier<

A friend of mine brought over a BIG Threshold amplifier one time and we ran that amp out of power. I think that amp was rated at something like 400 or 450 watts/channel into 8 Ohms. We shook an apartment building. No damage to the speakers. Our hearing on the other hand. . . I can see how 1kw/channel might "open them up" at volume.

I had been using a 250watt/channel ESS amplifier (which looks suspiciously Phase Linear-ish inside and out) with an SAE 2900 preamp, but the ESS died dramatically completely destroying a pair of AR2ax systems I had replaced the woofers and pots in. I've never seen the aftermath of a speaker "explosion" before. The crossovers were shreds and the speakers were "welded" in full-out throw and there were bits of surround literally feet from the cabinets.

I keep seeing the references to ADCOM gear. I've never played with any of it. I thought about trying to pick-up some Dynakit tube amps on ebay, but decided they didn't have enough umph for these speakers and they surely wouldn't fit where the boss wants them to go. I'll look for some ADCOM equipment and see if I think I can "sneak" it into the cabinet.

Thank you, again, for your response.

Bret

[Guest]

I recently purchased an AR9 in extremely good condition except of course for all the foam surrounds. I replaced the surrounds ( PartsExpress ) but left everything else as is. The only other thing that needs replacing is the square foam around the upper midrange and I am looking for something suitable. I want the speakers to be as original as possible. The only other item is the wood veneer and that looks like it needs some lemon oil because the areas that where covered by the grills look darker and less faded. Maybe someone has some ideas on restoring the veneer to original like condition.

I am using an NAD 2200 power amp with the soft clipping circuit turned on. The NAD produces up to 675 watt peaks into 4 ohms but is normally a 100 watt/8 ohms, 200 watt/4 ohms amp. I have never as yet turned it on full power as it might wake the neighborhood and frighten the cats.

Julian

[ar_pro]

Faded color is a very common occurrence, Julian...the majority of original owners seem to have kept at least the woofer grilles in place, and usually the front, too. I've never had any luck in getting faded areas to match the darker, unfaded veneer with oiling, so I went ahead and fine-sanded the cabinets, and then re-stained and sealed the finish. The result is a very close color match between areas that were miles apart before refinishing. I run the 9s without their grilles now (I also got rid of the cheesey vinyl appliques that surround the level control switches), and they look very sharp - most uninformed visitors assume that they're current-model loudspeakers.

[Guest]

>so I went ahead and fine-sanded the cabinets<

When you did this, did you fine sand them until there essentially was no finish left or did you just do that very lightly to prepare the surface to take stain?

I've been very reluctant to even try this. I tried refinishing some old furniture a long time ago and it didn't work-out very well. (read: I ended-up giving it away to someone so they could repair my damage) My 9 cabinets are okay, but a friend's 10pi cabinets could use some serious work.

Bret

[tysontom]

>I have two issues with trying to approximate the sound I had

>in the by-gone days of hifi heaven.

>

>Issue #1:

>

>I’m trying to be careful. I have a pair of AR9s I bought in

>late ‘78 or early ‘79. The tweeters were replaced after

>“The Infamous Drunk Roommate Finds the Tape Monitor Switch

>Incident of 1979.” My memory is that the original tweeters

>were not ferrofluid filled, but the replacements ordered

>later that same day were. These speakers were retired in

>1993 when the baby arrived and the foam gave-up. They have

>been in climate-controlled storage since 1994.

Both the upper-midrange driver (1-1/2" dome that covered the range of 1200 to 7000 Hz.) and the 3/4" tweeter (covered the range above 7000 Hz.) were ferrofluid-cooled drivers. "The Infamous Drunk Roommate" caused the reveiver to go into gross clipping, and no tweeter -- regardless of its design -- can handle gross amplifier clipping for more than a second or two.

>

>I have spoken to Mr. Tidwell at Layne and have read

>everything I can here. There is no reason for me to doubt

>anything I have learned, but I’m reading things that are

>either contradictory or beyond my comprehension.

You should treat everything you have read or heard regarding this subject with a certain amount of caution and doubt. Use various forums and sources to validate any claims or assertions about improving the quality of your AR-9s by substituting original-stock components with after-market components.

>I believe it was Mr. Kantor, if not I apologize, who wrote

>that replacing the electrolytic capacitors with

>polypropylene or others might have the effect of changing

>the speaker system’s voice. Then I read with interest the

>article about refurbishing the AR94 reproduced from TNT

>Audio. And Layne is recommending that I replace the 8" AR

>driver with a polypropylene driver.

I suspect that Mr. Kantor is being polite, and trying not to step on toes. I would not be not be so diplomatic; and in my opinion, there is absolutely nothing wrong with electrolytic capacitors -- "computer-grade, bipolar electrolytic" capacitors -- that AR used in all its big speakers after about 1974. They do what they were intended to do. Why change them? And will the change to polypropylene caps "improve" the sound? I doubt it, but to verify any improvement, you would either have to measure the results in an anechoic chamber or perhaps take two AR-9s, one with the stock crossover and another with a modified crossover, and perform double-blind A-B tests on them using a panel of different listeners. The differences would be subtle -- perhaps barely audible -- and the results might be worse. Also, replacing the 8-inch paper cone midrange with polypropylene 8-inch driver should be approached with caution. The stock 8-inch driver has a specific sensitivity, resonance, response curve, etc., that directly affects the smoothness and accuracy of that speaker. Changing that driver with another eight-inch driver would almost definitely affect the sound quality of the speaker, perhaps making it worse. Remember, too, that lowly 'ole paper -- as formulated for speaker cones with the vacuum process and felting -- is simply one of the best materials ever found for resonance-free response in its operating range.

>

>My concern is that anything I do to my 9s other than restore

>them exactly the way they were is going to change the

>speakers’ designed voice. I apologize to anyone whose toes

>I am stepping on, but I’m not sure I want my speakers to

>sound better. As I recall them, the 9LS model used

>polypropylene drivers and, well, I never thought they

>sounded as good as my plain-ol’ 9s. My best recollection is

>that the 9LSs had a very “up-front” sound compared to a,

>what?, mellow?, deep?, sound from the 9s.

Well, you hit the "nail on the head." If you want the AR-9s to sound the way they originally did, don't modify them. Restore them to their original design. Tim Holl, designer of the AR-9, spent a long time with many engineers, designing the AR-9, 90 and other AR speakers in the late-70s, early-80s period. The full resources of AR's engineering facilities, including anechoic chambers, semi-reverberant chambers and such were used to design this speaker. It is one of the most documented design efforts in the history of high fidelity. There is probably no way to know how many thousands of engineering manhours were spent designing and refining this loudspeaker, so why should someone's snap judgement that by simply substituting polypropolene for the midrange or changing the type caps in the crossover be a valid reason for improvement? The AR-9 stands on its own merits as one of the finest speakers ever.

>

>What receiver would anyone suggest, preferably not esoteric,

>preferably vintage, preferably not the size or weight of a

>Pioneer SX-1980? It has to “fit in the cabinet.” I know. .

>. Anathema. Stereo, no home theater. I like analog FM

>dials. I need current and obviously it would have to be

>low-impedance tolerant. The room is large (31' x 22') and

>the speakers have to be placed on the long wall. I don’t

>get to listen to Led Zeppelin IV at ear-bleed volumes

>anymore (while anyone’s home, anyhow) but Saint-Sean’s

>Symphony #3 can’t be listened to except at some volume. I

>used to like my Kenwood KR-9600 but have read unappealing

>things about them as they age. I might be able to fudge a

>pair of slim power-amps “hidden” here and there but pure

>separates are almost certainly out.

>

Remember that the AR-9 needs, and can absorb, large amounts of power. It is a low-impedance speaker, so an amplifier with lots of high-current capability is a must to extract the most from those speakers. Someone mentioned Adcom amps, and I have also had great success with these excellent amplifiers. The 5500 or 5800 series will work extremely well with AR-9s, and will not be affected by the demands of current into the 4-ohm impedance. Anything in the 150-300 watts-per-channel into low impedances will work pretty well with the difficult load such as the AR-9. The amp should also have good headroom, 1.5-to-3.0 dB, in order to handle peaks well, but most of these amplifiers have adequate headroom. Some of the NAD amps and high-power receivers will drive the AR-9s quite well. I used to drive my AR-9s with an over-kill MacIntosh MC2500 amplifier, and I saw 1000+ watt peaks (pegging the needles and bringing on the red-lights) on several occasions with no adverse affects on the speakers. I once threw a dedicated, 20-amp breaker doing this, but with ears "ringing," I soon learned that bringing the house down with these very loud SPL levels was simply not necessary for realistic sound reproduction.

--Tom Tyson

[ar_pro]

It's a pretty straightforward procedure, Bret...assuming no water-stains or gross veneer damage, it comes down to four steps:

1.) Remove two decade's worth of Pledge, polish & furniture oil with a diluted cleaner like Formby's.

2.) Carefully hand-sand (do NOT use a palm sander!!) with a good sanding block, following the grain from the top of the speaker to the bottom - repeat this procedure as you work your way across the surface to the speaker's other edge. Repeat all of your sanding using progressively lighter grades of sandpaper...I believe that I started with #150 or #200, and wound up with #400 paper (if in doubt, always use a lighter grade to start). You may have to sand the unfaded areas a bit more, to approximate the faded veneer's shade. Bear in mind that your speakers have already received a final-finish when they were new...it won't be like sanding rough wood, so you'll need to go easy, and sand slowly! Thoroughly remove all of the dust with a tack rag.

3.) The surface can be stained to the desired color at this point - I used a combination mix of Minwax Walnut, Special Walnut, Maple, & Golden Oak to get a VERY close match to the original AR color. A little goes a long way! Wipe the surface with clean, lint-free rags until it's almost dry (this previously-stained veneer will NOT need much additional color!), and then park your speakers in a dry & dust free environment for several days. If you need to, you can "adjust" the color by spot-staining any areas that seem too light, but go easy - it's a project that'll take time, because you will need to let the surface dry in order to properly evaluate the color.

4.) Finish - I chose to use a semi-matte poly spray coat that will never need oil or polish. In order to get as smooth a surface as the AR original (three coats of poly were applied), I used paper towels to rub down the surface between applications - very smooth!

That's all pretty simple, but refinishing the AR-9 presents a number of additional considerations:

1.) All of the drivers will need to be removed, and the speaker holes properly sealed for the duration of the project.

2.) The Acoustic Blanket is a tough work-around - it cannot be removed and replaced, so you'll have to sand & stain right up to it's edge. Removing dust is not pleasant, so you might want to mask it off.

4.) Does anyone like the look of that cheap vinyl applique around the level-control switches? Not me, so I peeled it off.

3.) Now would be a good time to re-paint the back of the cabinet (matte black looks nice) and the front edges - you'll need to mask the newly-finished surfaces.

4.) Also a good time to install floor spikes and better speaker posts!

[Guest]

>don't modify them. Restore them to their original design.<

I appreciate your take and respect your perspective. I was "fighting" the advice I'd been given. Both intellectually and on a gut-level I knew better than to give my beloved speakers a "new" sound. I just needed to be told I wasn't being "silly."

They go-back together just the way they come apart. That's the final, irrevocable conclusion I've drawn.

I've been looking at ebay for adcom amps. Even the used ones look like budget-busters to me. The first receiver I used with these was a Yamaha R7. It was only 60 or 65w/channel, but it was low impedience tolerant. Obviously I couldn't shake the house, but at moderated levels the sound didn't stink.

Just for funsies I've looked for Accuphase and Threshold equipment, too. Adcom is the most reasonably priced of those, so maybe I'll raid the penny jar.

Bret

[Guest]

>Why change them?<

I apologize for making this a two-part reply, but in thinking about your comments I wanted to be certain that I understood you perfectly.

I was thinking of replacing these capacitors because of age - with new ones like those I remove. Surely any electrolytic twwenty-four years old is going to have changed value, right? I would suspect they have, particularly since they haven't had any current through them in nine years.

And while we are on the subject of crossover components, there is no reason for me to think my chokes are bad, but how would one test or measure a value on a choke? I'm sure it is beyond my doing, but how is it done?

Bret

[Guest]

I'm not sure that I'm going to try to refinish my 9s. They're in pretty okay shape, but I have printed-off your instructions and filed them away for a time I might need to do that.

Don't you worry that one day you'll want to get back to the stain and can't with polyurethane on top? Like I said, I know nothing about refinishing furniture.

Bret

[ar_pro]

Actually, the poly is easy to remove with lacquer thinner, should you ever need to do so. Unsealed finishes can look nice, if they're oiled regularly...their downside is accumulated gunk, and susceptibility to water stains. I'd like to have a dollar for every AR speaker that I've seen with a glass ring, or water stain from a potted plant!

[ToastedAlmond]

If space is really an issue, and it precludes separates, I have had great luck driving the 9's with a Carver "150" Receiver. Also called the Carver Receiver, it does about 160 wpc into 8 ohms. There is no 4 ohm info, but it is doing a credible job to my ears. Prior to these 9's, this receiver drove 3ohm and less rigs. I used 4 Polk RTA 11TL speakers (6 ohms) with an original Dynaco Quadaptor. Receiver never even got warm.

I have some space issues myself. I have an Onkyo M-504 power amp, that I am going to use to drive the 9's woofs, and take some load off that Carver.

Toasted Almond

[Guest Nigel]

>how would one test or measure a value on a choke? I'm sure

>it is beyond my doing, but how is it done?

>

Hi Bret;

With a piece of equipment called an LCR meter, or impedance meter. They will measure inductance, capacitance and resistance.

I have two pairs of AR9s, one set purchased refoamed, and the other set waiting for refoaming. And that is probably all that they will get. Someday they will be part of a home theatre & audio system.

I am using an Onkyo TX-8500 receiver (1976/77 vintage) to drive the 9s. Works well, will wake the neighbors. It is a BIG receiver, and heavy ~65lbs. The TX-8500 is comparable to an Adcom 545 II.

If you can afford it, an Adcom 5802 or a pair is the way to go. If not, starting with an Adcom 545 II (or 545 or 5400) is a low budget way to start, then later get a second one to vertically bi-amp the 9's. In the middle are the 555, 555 II and 5500.

Nigel

[Guest]

>If you can afford it, an Adcom 5802 or a pair

I'm afraid this is going to be a "in my dreams" goal to shoot-at - notice I didn't say "for." :-)

I'v been putting-off the restoration of the 9s for a few reasons, money is one minor consideration, the yelling I expected when I bring them into the "living room" was going to be another.

Then, strangely, the spouse said, "You can have your big speakers if you want them."

Uh oh.

Bret - waiting for the other shoe to drop.

[Guest]

>If space is really an issue, and it precludes separates, I have had great luck driving the 9's with a Carver "150" Receiver.<

I know it can be done. I've listened to them on receivers as "small" as a Heathkit AR-15 and they were still respectable. I suppose when I start thinking about it, they've usually been driven by a receiver. Either a Yamaha at about 65w/channel into 8Ohms, a Kenwood KR-9600 (I remember it as being 160w/channel @ 8Ohms), the Pioneer SX-1980 at 270w/channel, and then that ESS amp.

My Dad's Carver. . .2000? 2600? receiver is off being repaired . . . I offered to buy it for $10 and pay the repair costs, but he wouldn't go for it! I think his is about 125w/channel.

I'm intrigued by the idea of Adcom. . . probably because it's something I've never owned or listened-to. I've been thinking about what could come OUT of the cabinet so I could sneak separates in there. I don't think the VCR in there has ever been used, so who'd miss it? And if I dumped the Pioneer LaserDisk/CD player and got a little bitty Sony CD/DVD player. . .

I guess you see I'm talking myself into trouble.

Bret

[ToastedAlmond]

If your Dad's Carver is the "Receiver 2000", that was rated at 200wpc @ 8 ohms, and was basically the big brother to the Receiver 150, and Receiver 900 (90wpc). I would get him something nice for his birthday. Something like a nice, NEW, Pioneer Dolby Digital receiver. Then try for that Carver again.

Toasted Almond

[Guest Sean]

I would stick with the original paper 8" mid-woofer and avoid the poly unit. It tends to sound harsher and much more forward in my opinion.

As to changing the innards of the speaker, have at it. I would replace all of the internal wiring, caps and get rid of those HORRIBLE binding posts. While one could change the inductors ( coils ), this "upgrade" would offer the least bang for the buck out of those already mentioned. While you are at it, solder all of the connections. Adding a small amount of damping material ( fiberglass preferred but Acousta-Stuf will work ) is also beneficial. As to changing the sound of the speaker, you better believe it will. I have done all of the above and would do the same thing all over again with no hesitation what so ever. The sound is FAR more transparent with better detail. For the "unbelievers", caps ain't caps and wire ain't wire.

As far as amplification goes, i see people tossing out the name of Adcom. I would avoid the 5800, 555, 5500, etc... If you really want to go with an Adcom sometime down the road, i would suggest the 5802. It is miles ahead of the other amps in every aspect. I say this having owned 5 different Adcom products.

As far as Carver products go, i would avoid the mass majority of these also. The exception to this "rule" would be the Sunfire or Lightstar amps. Either of these would be a very solid match for the 9's. As you'll find out, 9's really need a GOB of power to sound their best and i do mean a GOB. 400 wpc @ 4 ohms is not nearly enough. I will say that the "baby" Sunfire ( 300 @ 8 / 600 @ 4 ) does a credible job but lacks bass "slam" with the 9's. Given the high efficiency / low bias design of the Sunfire / Lightstar amps, they do sound best with a little bit of gain cranked into them. They are not the most refined amps in terms of low level detail but are easily on par ( actually well above ) with the other amps being mentioned here. I make these comments based on the past experience that i've had owning over a dozen different Bob Carver built / designed products. Sean

>

[Guest]

>Bret, I believe that you're correct regarding the sound of

>the 9LS, which was to my ears, inferior in every way to the

>original Model 9. The plastic 8" driver was certainly an

>important factor in the voice of this design, and I'll bet

>that substituting it for your 9's original driver could be a

>mistake. I'm biased in favor of restoring vintage

>loudspeakers to original condition, without "improving"

>them, although I think that practical aspects of

>construction (like the replacement of friction-fit

>connections with soldered joints) definitely has a place.

>Also, I'm pretty sure that the 9 used ferro-fluid tweeters

>from the beginning (it's in the lit)...when I read about the

>delicate nature of the AR tweeter, or how easy they are to

>burn out, I have to wonder why I've never lost one! I'm

>going to chalk it up to amplifier power...LOTS of amplifier

>power. My speakers have always had plenty of clean juice

>available (a variety of models from McIntosh, Crown, &

>Adcom), and have never driven an amplifier into clipping or

>overload, resulting in (I believe) long-lived tweeters. If

>you check out some of the many posts, you'll find that Mac &

>Adcom (and Hafler & Dyna) are real favorites...very stable &

>reliable, and in the case of the Adcom 555II, a LOT of power

>for not too much money. I'll bet that you could latch onto

>an Adcom preamp (they made an excellent passive preamp that

>sells on ebay for about 100 bucks) & power amplifier that

>wouldn't take up much more space than those big Japanese

>receivers...it would be a great match for your classic

>speakers!