[AR-10 Pi Capacitor Question]

9 hours ago, Aadams said:

You have new caps in your AR9s.  Put on a favorite recording and compare to the 10pis.  They won't sound the same but if they sound equally distortion free you are good to go.  I wouldn't change them.

So I've now spent a couple of hours critical listening at moderately loud volumes, as well as a couple hours playing music in the background while I play with the kid. I can't hear any clear deficiency. I don't hear any unwanted distortion at all between the -10pi's and the -9's. . I'm going to take your advice and leave the Spragues in place. It's a treat to hear the original caps.

Thanks for the heads-up @DavidR. I may open these up again in the next few weeks. I'll take that cap out of circuit and test it if I do.

[AR-10 Pi Capacitor Question]

Would you replace Sprague capacitors in the AR-10 Pi?

I recently did some horsetrading with another hi-fi enthusiast and acquired a pair of -10 Pi's. Overall in good shape. No grills. Tonegen woofers from AR in the late-80's. A dimple on each tweeter but everything functioning. I went into it thinking I'd need to replace the caps. On my first test, there was distortion in the very low end during loud passages. Not much of an acoustic seal so I wasn't surprised.

Today I opened them up and this is the first pair of AR's that I've come across that have Sprague caps (for all but the 100mf cap which is silver and in a different typeface). I heard that Sprague caps are often still in spec, so I closed them back up, sealing the woofer using duct putty (anachronistic, but I get a good seal and they carry it at Lowe's). The woofer distortion is gone now after playing back the same material. The midrange and tweeter sound okay to me on initial retesting.

I'm sure the caps have drifted somewhat, but if everything is functioning and the drivers "sound" enough alike, would you still replace them seeing as they're almost 50 years old?

As for listening, I think these are one of my favorite ARs, behind the -9. The tone controls are interesting on this one.

[AR-9 First Restoration]

Thanks @Aadams! I’ll try adjusting angle as I keep testing. 

[AR-9 First Restoration]

My music room has recently changed. As I mentioned above, we live in an old house with mostly smaller rooms. We just finished an attic renovation and that’s where my listening space is now. 

I’ve been cycling through my collection of speakers in the new space…partly to get to experience them all there, but mostly to see what works best. I’ve tried the -9’s, -3a’s, (a new to me pair of) 10pi’s, and KLH Model Fives. 

Surprisingly, even though they’re the largest speakers, the -9’s to my ear still sound the best in that space. The bass goes low effortlessly but is clear and doesn’t boom. Granted, this is with the EQ recommendations mentioned in the manual. 

So my question is, what about the design of the -9’s allows them to work so well in less than optimum, smaller room settings? 

Picture is of the beauties in their new space. Distance between vertical arrays is just under 6ft. 

[Model Five Restoration and Some Questions]

Thanks for the offer and your prior advice, @genek. I know what I did wrong, I just need to practice more. I’ll post some pictures of that area when I’m ready to circle back around to working on these. For now I can hide the corner with the sand through against the wall and no one who comes in the room will be the wiser.

Frankly I’m just glad the grills and grill cloth came out so nicely. I think those being so neat helps hide some of my shortcomings. I’ve been avoiding working with grills because I had very limited experience working with cloth. But this weekend I did these, a pair of AR- 4x’s, and I redid my AR-6’s. I feel confident enough that I’m going to redo my Model Fourteens with the leftover cloth I had from this project. 
 

 

[Model Five Restoration and Some Questions]

Well it’s been a few months but I finished the Fives today (for now anyway). 
 

My attempted touch ups of the sanded through areas….didn’t go so great. After a few attempts I ended up with a result that almost highlights those areas. It is what it is (for now). In the future I may sand through the varnish and reattempt touch ups. Thankfully those areas are small. I’ve learned that this hobby (for me) is very recursive; I’ll go back and fix mistakes once my skills have improved.
 

As for the finish, I decided to use glossy spar varnish. It’s not true to what was on the veneers originally, but I think it makes the veneers pop. This was my first use of spar. 
 

I replaced all the caps and replaced the resistors with beefier 10w resistors as mentioned on this board. Resealed all the woofers and midrange drivers. 
 

The project concluded today when my wife and I made new grill frames and installed fabric. I haven’t wanted to play these speakers much because I’ve been afraid my toddler would push in dust caps without grills on. I used Guilford of Maine’s wheat colored acoustic fabric. It’s enough off white that it looks somewhat aged, but still very clean and bright.
 

I moved my AR9’s out of my main listening area to install these. They’re less than have the size of 9’s but they’re far from half the sound. I really love these after only a few hours of critical listening. I can understand why someone in the 60s or 70s would have chosen these over AR-3a’s between the great sound, lower cost, and higher impedance. Beautiful speakers. 

[Model Fourteen S]

Hung them up today. I’ll touch up and paint the new rails soon. 
 

These are really fantastic little speakers. Not much bass of course, but upping the bass on my receiver’s tone controls a couple clicks makes me feel like I’m not missing much. 

[Model Fourteen S]

Looked around. Here's that same stamp on a vintage Swedish credenza I found on Etsy. So maybe KLH outsourced production of the 14 to Sweden?

[Model Fourteen S]

[Model Fourteen S]

I recently purchased 4 Model Fourteen S speakers and I have a question.

tl;dr: How much of a benefit would there be to resealing the cloth surrounds on the Twelve Point Five drivers in the Model Fourteen S being that it's a ported speaker?

So I bought four of these to run in my quad setup. We recently finished a remodel of our attic and I've been putting a music room back together in the new space. Before these, the only speakers that I owned two pairs of were AR-3a's which I ran in room briefly. Those speakers were far too much for the quad space which is roughly 11.5' x 9.5'. I read about the Model Fourteen S and thought they'd be a more suitable substitute for the space.

I took them apart to recap them, and that's when I realized I would need to take off the grill cloth in order to get to the front of the drivers. Currently, all 8 Twelve Point Five drivers are working and the grill cloth on each speaker ranges from Good to Excellent. They sound very good as well...I hear no rattling or other noise and they all "sound" the same to me so far (although that could change as I get more time logged listening to them).

All of that considered, is there good reason I should go ahead and reseal them as the Service Bulletin indicates? I understand the seal needing to be excellent in an acoustic suspension design, but does it matter as much since the Fourteen S is ported?

Also, a couple of other things from taking these apart:

At some point KLH eliminated the Compensated Amp input and left only screw terminals. Three of my four have the CA RCA jack while the one with the latest serial number (in the 7000s) only has screw terminals.

Also, one each in the pairs I bought had a large stamp on the inside of the back plate which reads "Karlit Tempo" and "Made in Sweden." Was the back plate or its material made in Sweden? The whole speaker? The terminal plate of course says Cambridge, Mass.

I'll post photos in the replies.

Thanks in advance,

George

[Older AR's or, just buy new speakers?]

On 10/1/2023 at 6:37 PM, Aadams said:

Good write up. I see why the "44" is a test track.  I tried the Bolcom and couldn't make contact.   There is a lot of value in a properly working AR.  I am sure by now there must  be new speakers at least as good as an AR9 but I am skeptical they are $10,000 or $15,000 better. 

Thanks. The Bolcom isn’t for everyone for sure. But a lot of those 70s Nonesuch avant-grade albums are really well recorded and mastered by Bob Ludwig. The Bolcom (and the B-side piece by William Albright) in particular has a huge dynamic range. They also tend to be cheap. I got my copy for $5 and it looked unplayed, apparently the previous owner didn’t make contact with the music either. 

[Older AR's or, just buy new speakers?]

I've been enjoying AR speakers for two years now. I was born in the mid-80s and grew up listening to my dad's Bose 501's, mostly with CD's. When I was 15 I started collecting records, including new records at a time when that was near its nadir. I had an extremely basic system through college, a first career and grad school, but those records traveled with me across the country. Not long after moving to New England, I picked up a pretty busted up pair of 6s. I fixed those up and have been hooked on AR and other New England-manufactured speakers since. I've been fortunate to have some expendable funds the past couple years and have put some towards acquiring relatively cheap AR sets and mostly performing necessary repairs myself. My main system is a pair of AR-9's, but my most used system is in our living room where I've set up 91's. I'm a parent and this is where me and the kid listen to most of our music. I'll also have my quad system up and running again soon (quad is another weird, new obsession since I inherited my grandfather's receiver) which is composed of four 3a's. I've also heard some others, including the AR-2x, -4x, -8, -92, -303, and the Rock Partner.  

I'd rather spend the 10K on the AR-1's although I agree they'd be more of a collector's item rather than something I drove daily. I prefer AR's for a few reasons. First, I agree with ARSurround that most modern system demonstrations I've heard sound antiseptic, and I wouldn't describe any of the AR's I've heard that way.

Second, AR's and the -9's in particular, suit my musical tastes well. I often listen to music that punches close to 20hz. I love electronic music and many of those can go very low. The track "1st 44" by Aphex Twin is a system tester for me. And the 9's make each of those numerous bass punches feel authoritative. I've also heard some avant-garde organ music I love recently, "Black Host" by William Bolcom. Some of the notes in that you feel more than you hear it seems. I have eclectic tastes, and whatever I'm listening to, whether it's John Zorn or Harry Nilsson, my ears are referencing the 9's now. I want an all-in-one, full spectrum loudspeaker system and AR delivers.

Finally, I think I'll be sentimental about AR equipment because it's the first nice equipment I've ever had. It's not new, but I bought it, I fixed it, and I'm enjoying it. Beyond the sound of the speakers, I enjoy that they were designed and manufactured in the US and specifically New England. Almost all my equipment is older than I am (some significantly) and I feel like I'm in danger of being nostalgic about a time I never knew.

So give me 10K and I'll take the AR-1's. I want to hear what the best loudspeaker system in the 50's sounded like.

[Punctured cloth surround AR-4x]

29 minutes ago, JKent said:

Remember--the 4x doesn't have the kind of acoustic seal other ARs do. The dust cap is porous. I seem to recall Roy saying the 4x doesn't really need to be re-doped, usually. I'm thinking less is more in the case of the 4x.

I didn’t know that. Thank you @JKent. This pair definitely needed to be redoped at least once. When I got them, they appeared to have never been opened yet had no seal at all. 
 

I’ll hold off any redoping a second time. 

[Punctured cloth surround AR-4x]

I followed @Aadams advice. I picked up a high thread count color sample and a fabric adhesive called Unique Stitch from Jo-Ann’s. I tested the adhesive and it didn’t seem to add much stiffness to the fabric. Unique Stitch is also supposed to hold up under machine washing, so hopefully the patch will hold up with the movement of the woofer. 
 

I made a small circular patch, glued it in place, and applied the goo after the adhesive cured. It’s difficult to see the patch from these backlit photos, but you can see they puncture damage in one photo and not in the after photo. 
 

I’ve reinstalled the woofer into the cabinet and there is an OK acoustic seal (woofer fully bounces back after 3/4 sec or so). At this point I just need to drive them for awhile and hope the patch holds on. I’m also considering applying a second layer of the woofer sealant goo…much of the woofer doesn’t feel tacky, like the cloth absorbed it mostly. 

[Model Five Restoration and Some Questions]

@genekThanks so much for your thorough response. I’m going to ditch the Danish Oil and go your route. Hopefully I’ll have some results to post in the next couple of weeks. 

[Model Five Restoration and Some Questions]

Hi everyone,

When I went to Boston and bought my AR-91's, I also added a pretty beaten up pair of Model Fives to my collection. I only paid $50 for them which I figure is about right for the shape they were in. These photos are of the worst sides of the cabinets. Not sure what the black on the bottom of one is (mold?). Someone also definitely put a potted plant on top of one.

Between them, both tweeters and woofers are working, but both of the midrange drivers in one cabinet were out. I've ordered and received replacements for those, both made in the same year as my working midrange drivers (1969). I've also ordered npe caps from Dayton Audio and 15w resistors from Madisound. While I wait for parts, I figured I'd share my progress and ask a couple questions.

I spent a day this week working on the cabinets. I started by painting the baffles flat black. I first saw this in the excellent video series by @thr33p4c. In addition to this board, those videos have been a terrific resource. I got uneven results: one cabinet had a little more sheen. I flattened out the sheen using a some #1 steel wool.

Based on a thread I found here, I stripped the old finish using Blue Bear Paint and Urethane Stripper. I had the same experience mentioned in the previous thread: the old finish came off as a sludge using a putty knife. It seemed to me that a significant amount of the previous finish came off using the stripper. I hand-sanded the edges of the cabinets then used an orbital sander for the majority of the work.

There are some corner bashes and small bits of missing veneer on each cabinet. I'm going to try Kwikwood mixed with Mixol 22, again another decision based off the Novalux videos. After that has set, I'm going to apply dark walnut Danish oil. I plan on doing three coats over as many days while I work on the crossovers. While all that is going on, I'll seal the woofers and midrange drivers with The Goop™. Neither of my grills are in good shape, so I'm planning on making new ones, something that would be new for me.

Here's some questions:

- Despite best efforts, I still went through veneer on a couple edges. My plan is to use a small amount of paint on these spots before the danish oil. Does anyone have a recommendation for a paint brand and color for this touch-up work?

- What's a recommended grill cloth for these? Is it possible to find a comparable material at a store like Jo-Ann's?

- What is proper positioning for these? I saw the ad in the library said floor or shelf. If placed on the floor, is it better to use stands?

[AR-91 Provenance?]

Here’s some photos of the veneers including some scratches that blend in well. The beveled tops to match the grills makes enough of a difference that my spouse commented on how clean they look. 

[AR-91 Provenance?]

1 hour ago, Stimpy said:

My wife used to have TSW 410s.  A great speaker, with good dynamics.  A more lively sound, with a slightly hotter high end, than our AR 9 variants.

Well, the 100uF Solen film cap would run over $55 dollars each.  So, you'd spend quite a bit just to replace those 2 shunt caps.  NPE's are fine there.

I’ve been considering picking up a pair of TSW-115p’s that are near me. That’s the powered version of that line. I take a mini-system with me on vacations: a Sound Burger record player and a pair of powered speakers. I think having the powered TSW would be a hoot if the electronics are in good shape. 

I’ve paid for that Solen capacitor before. Can’t say I’m eager to buy them again so I’m good leaving it as is. 

[AR-91 Provenance?]

@DavidR I haven’t heard the 610’s (or any TSW speaker) but I imagine you’re right about the 91’s mid being better. The mids and tweeters from the 9 series are terrific. 

@Stimpy Thanks for the info about the capacitor. Some previous tech really took care of these so I assumed they were left in position because they were still within spec  

 

[AR-91 Provenance?]

Earlier this year I picked up a pair of 92’s that I recapped and fell in love with. I’ve been keeping my eye out for a pair of 91’s at a decent price because I wanted the 12” woofer and real veneers. Yesterday I bought a pair in Boston. 
 

The seller didn’t know about work done to them. He said his father-in-law had them “rewired” at some point. I figured that could be either very good or very bad. 
 

Well it was my lucky day. When I got home, I opened one up and found that it had been recapped. I’ve attached a photo of the work done. All capacitors replaced with Solen capacitors except for the 100uF cap which was left in place. Someone also went to the trouble of replacing the deteriorated acoustic blanket around the tweeters and mids. The veneers are also in great shape. There are some scratches in the veneer but they are well hidden, which makes me think they were possibly treated with RAF?
 

They sound phenomenal. I’ve only listened to them for a few hours but I’m so pleased. 
 

I’m wondering, does anyone know who did this work? Maybe it was you?

[Punctured cloth surround AR-4x]

24 minutes ago, Aadams said:

Can't recall seeing a repair like this in the forum. 

Oh god I've gone and done something novel

The more I look at this, the smaller it seems the puncture is. The sort of diagonal line in the blue area is not a full tear. The actual puncture is quite small.

26 minutes ago, Aadams said:

I would repair it on the back side with a narrow strip of high count cotton attached with the least amount of flexible fabric adhesive possible, then dope on the front side with RoyC goop.

I think that could work. And the puncture is so small, the patch would hopefully not (significantly) affect woofer performance.

[Punctured cloth surround AR-4x]

Neither. It’s in the blue circle 

[Punctured cloth surround AR-4x]

On second thought, here's a photo. It's a pretty minute tear I think.

[Punctured cloth surround AR-4x]

Well I went and made a real amateur screw-up. While screwing a woofer into the cabinet of a 4x I picked up, my screwdriver slipped and I punctured the cloth surround on one of the woofers. Very small screw driver puncture through the surround away from the cone. All the material is still there. Is there any way I can seal this surround? No picture included because it doesn't photograph well. Doing some tests with the speaker reassembled, that woofer is making a raspberry sound on low bass notes at higher volumes, I'm assuming since it's not sealing.

I have a small jar of the sealant Vintage AR sells (and maybe @RoyC formulated??) but I don't know if that would work in this situation, nor do I want to go globbing it on without checking.

Thanks

[AR-9 First Restoration]

@frankmarsi It's an old house and I don't have larger rooms to work with. The room size certainly isn't optimal, but after listening to these speakers for nearly a year in this spot, it's hard to imagine being more pleased. That being said, I do plan on upgrading amps in the next year or so. I want something that can do at least 400W into 4 ohms. Currently I have an 80's Luxman that was advertised as delivering 170W into 4 ohms. A Nakamichi PA-7 would fit in well with my other equipment so that's what I'm considering.

I actually purchased a second pair of AR-9s over the winter at I think a great price. I plan on gifting my current 9's to my dad and recapping this second pair as my set. And all of my equipment is moving into a room slightly larger than this one later this year. If you think a pair of 9's is too big for that space ... I'm putting those 9's as a stereo set and a separate quad setup of AR-3a's into the new space.

Oh, and I could detect some vibrations between the wood pedestal built into the 9's and the wood floor. I ended up putting felt furniture pads on the base and that solved the problem.