Stimpy
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Posts posted by Stimpy
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2 hours ago, briodo said:
I purchased the replacement capacitors for 2 pairs of 91's. I'm doing a two for one so to speak, having a pair of AR91's requiring woofer surrounds and recap. Cabinets are 9 out of 10. It's clear from others work in this area that NPE's from that era may need to be replaced, but mylar ones are likely to be good. I have a meter with capacitance reading, and will verify before replacing.
Four woofers have been refoamed. I use shims after carefully cutting around the outside of dust cap leaving a small hinge so I can reglue. Aileen's tacky glue works perfectly for all aspects of the job. AND drys clear. The cut lines are barely noticeable.
Also took a picture of the crossover board still inside one of the AR91's. It has the NPE's throughout. AR91 also has a brace from front to back placed between the woofer and midrange drivers, assuming to reduce cabinet flex from the woofer?? I'm thinking that may be an easy add to the AR58S. Any opinions on value of that brace?
Going to work on the crossover board removal next.
Beautiful work on the refoam. Well done.
Also, I just looked again at those 58 woofers. I didn't realize they were that horrible. It looks like someone glued a partial woofer on top of the AR woofer? What were they thinking? Brutal to see good woofers treated like that. I'm glad you had the back-up spares! And hopefully, you can pop out that UMR dome too?
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Yep those are 91 boards. And I didn't know that AR used T.I. caps. I believe those are Mylar. The Unicon caps were nice too. Both brands better than the black/red Callins capacitors in my AR90's.
Are you planning on a recap, prior to the swap?
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3 hours ago, lARrybody said:
Stimpy is right about the AR 91 and AR 92 boards sharing the same blank. The AR 91 crossover has 6 resisters compared to 5 resistors on the AR 92 crossover. Yes the AR 92 uses a 80uf cap on the woofer as opposed to the 100uf cap used on the AR 91. The AR 91 40uf cap is missing altogether. The 4uf, 8uf and 24 uf cap appear to be the same. I would not be surprised if the inductor coils have different values also. Just count the resisters (5 instead of 6) and Capacitors (4 instead of 5) to identify AR 92 boards. Identifying the inductor values will take more investigation. As others have said, my AR58s speakers never cease to amaze me.
Thanks! I occasionally know what I'm talking about. Just don't ask my wife for confirmation.
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There was a recent thread, about un-built LST cabinets, being found in a warehouse. But, this was in Italy, so not an easy proposition to get a pair here...!
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Make sure that you have the correct AR91 crossover boards. Those same "blanks" were used for both the AR91's and AR92's, which have different crossovers. The correct 91 board, has 5 capacitors, with the woofer cap being 100uF. The 92 board has 4 capacitors, with the woofer cap being an 80uF value. Some different inductors too.
As to the rest, that looks like a fair amount of work. Lots to fix. The woofers look usable to me, but will need to be well cleaned. Some huge surrounds on them too, which don't look correct. So, I'm glad they're being properly restored. Those are great speakers, and worth saving.
Good luck.
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Infinity RS4.5's or AR LST's? What a problem to have...! Congratulations.
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1 minute ago, ar_pro said:
Stimpy -
How does the side veneer look without the paint? Is it close to the color of the unpainted section?
Your idea for the stands is really interesting. I prefer the sound of the AR-91 with its tweeter at the same height as the AR-9.
Here's what Forum member Tom Tyson had to say about the Acoustic Blanket back in 2005:
They may not sound quite as good, but the acoustic-blanket stuff is 80% marketing, 20% functional, in my view at least.
I tend to agree. I'm completely biased about the appearance of the blanket and the vinyl stickers on the front panel, but listening to AR-9's in the far field - maybe 15-20 feet - I never missed the blanket. ☺️
Hey ar_pro,
The veneer completely matches. It's one solid piece, on the sides. I just need to finish the stripping process, to completely lift the black paint, and I think it'll look nice.
As to the blanket, I'd like to remove it, mainly due to the fact that would make the refinish process much easier. Nothing in the way then. But, I'd have to repaint again, after. Though, I guess I could try and veneer the fronts too?
I've been thinking about stands for a while. It's something I will definitely try, as the 90's look a bit squat, since to me they have a Napoleon Complex, compared to the 9's.
Oh, my listening room is 14x16'. Maybe not large enough? Another reason I guess I should leave the blanket? Though, Tom's comments are very interesting...
Stimpy
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2 hours ago, ka7niq said:
Stock, and do not remove the acoustic blanket, and if you already did, be thinking about how to make a new one.
Nothing too drastic yet, as the acoustic blanket is still in place. The only thing I've done to the cabinets, is to strip the polyurethane, that my brother applied (for whatever reason), along with the black paint. So, while I'll keep the stock design, for the front, I will not be repainting the black woofer trim on the sides. There's walnut veneer under that paint, and I do want to leave it exposed. With the side grills in place, the look will still appear stock, and no harm done.
One other variation I'm considering, is to make a short set of stands for my 90's. Something 6-sided, completely enclosed, and maybe filled, that the 90's can set on. The stands will bring the height of the 90's to the 9's. Or at least, match the height of the tweeters between the 2 models. Just for looks. Though, in my listening room, the extra height should improve treble response.
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3 hours ago, AmA732MX1 said:
The older Studio Reference towers were a tad bright, but over about 10 years and 5 revisions they dialed them in nicely. They have never had the bass energy though. An M & K sub works pretty well in my system. Glad to hear you are getting enjoyment out of your 90’s. I would love to spend some time listening to a properly restored pair. They are a very nice speaker for sure. I longed for a set of those like nothing else when they were new and for many years later. Who knows, I may still end up with a pair. ?
I've been doing exactly that, to my 90s. Or at least, trying to restore them. I recapped the crossovers, with Mundorf poly's and added new Mills resistors. I've replaced all driver surrounds, and added Dynamat to the baskets. I also added a couple of extra cross braces internally. The LMR tube enclosure has been reglued. I'm now working on the cabinets, stripping them down. Though, I'm not sure if I want to refinish them back to stock, or create a pair of Naked 90s? The only question is how to refinish the front, as the 90s aren't veneered on front. It's plywood.
(Thanks ar_pro)
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Back on topic. All this CES talk, reminds me of a speaker brand that might fit into our AR vs Paradigm discussion. Alon. Or Nola, whichever you find. Now there is a speaker line that sounds both vintage and new. Warm, relaxed, yet dynamic and detailed. I've heard Alon's at dealers, and Nola's at shows, and I've always been impressed with their sound. Plus, they sound good on solid state, but love tubes. A win-win.
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On 12/17/2019 at 9:34 AM, ka7niq said:
Bongo is dead too
Yes, I was too inexperienced as an audiophile, back when I had the widerange ribbons, and even lacked an amp to properly drive them. I WISH I had them now !
I met Brian, Jim Thiel, and Arnie Nudell at that CES. All 3 gone now...!
A funny thing though. I was in the Genesis Tech room, listening to their new speakers. Sounding very good, even in surround. But, over in the corner, was this diminutive, quiet man. He smiled at me, and asked if he could help, and how I liked the speakers? It was then that I realized it was Arnie! I got so flustered and tongue-tied, I couldn't answer...! I still regret that.
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17 minutes ago, ka7niq said:
Absolutely ! I met Brian way back in 1982, when I flew down from Seattle, to go to his shop in the Frisco Bay area. I owned the VMPS Widerange Ribbons back then, and returned them to Brian. He gave me my money back, and a pair of VMPS Supertowers. He just asked me to fly down and hear the Widerange Ribbons properly set up and powered. LOL, I was in my 20's, back in the 80's, and the big VMPS Supertowers were great for me back then. Big, forgiving speakers with stunning bass the VMPS Supertowers were. Just the thing for the Hard Rock I listened to back then.
I met Brian and Shirley, along with John Casler, and the great James Bongiorno (Zoot Suit and all), at CES 2004. Brian was demoing the RM30's and 215 sub, along with Jim's amps. A stunning system.
Widerange Ribbons! Wow. A truly rare creature. I wonder if you'd appreciate them more now?
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3 minutes ago, ka7niq said:
Yes, Brian and I have had our disagreements, but many agreements too
I miss Brian, really I do.
Me too. Very much so. A talented designer, than never got the respect that he was due.
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2 minutes ago, ka7niq said:
Cool !
I was just reading a thread by Carlspeak, where he tested some new ERSE Mylar Caps, and found fairly high ESR. On a recent order from ERSE, I needed to meet the minimum order requirement, so I ordered some ERSE Mylars I really did not need.
I just got an ESR Meter, so just for the hell of it, I measured the ESR of the new ERSE Mylar Caps. I was surprised how high it was, especially since they were right on the money as far as measured value goes.
As Carlspeak mentioned, this high ESR makes them an excellent choice for NPE replacement !
Higher than typical ESR, was why I tried the ClarityCaps. For poly's, they measure very similar to NPE's.
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4 minutes ago, ka7niq said:
Both, as long as the speakers "disappear". Actually, few speakers can "get out of their own way".
Hey ka7niq,
Off Topic. Didn't you used to hang out over at the VMPS Forum? I seem to remember you there? A RM40 owner? I remember you and Brian used to go to war at times.
Good stuff.
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3 minutes ago, ka7niq said:
Cool, and a great find ! I have never owned those, but have heard them, way back when. Do you plan to update their crossovers ?
Yes, I've already refreshed the crossovers. I used ClarityCap CSA polys on the dome tweeters, and ClarityCap ESA's on the dome mids. The parallel shunts were Bennic NPE's. I added Dayton foil bypass caps on all caps too.
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26 minutes ago, ka7niq said:
Very true! I found that they needed to be toed in, and they did need to be out from the back wall, before I got image depth. However, they lost too much Bass to leave them that way. I wound up with them toed in, but the corner of the speakers right against the back wall. I still lost a little bass, compared to them being all against the wall, but the improvement in imaging was worth it, to me. Still, I never gould get that "spooky" imaging out of them. I have been a "speaker junkie" since the 80's. I always seem to have between 3 and 5 pairs hanging around. I seem to remember that back when I had the old AR's, I also had B&W Matrix 801's and Vandersteen 2C Speakers, maybe I still had my old Celestion SL 6's ? All 3 of the speakers I just listed are capable of "Spooky Imaging". IOW, the speakers "Disappear" in the room. I was never able to get the AR's to image like that, in my room. YMMV
However, I remember the AR 9 and the AR 90 as big, pleasant sounding speakers, with room rattling bass.
I've had similar experiences to you. AR Vertical speakers can be hard to position, to get a good blend of frequency response and soundstage balance. But, AR's are more resolving than I think they're sometimes given credit for. The better their associated gear, the more their sound improves, including image width and depth.
I found this out by accident. I had just purchased a new-used preamp. I wasn't expecting anything drastic sound wise. But when I did a quick and dirty set up, for the new pre, and switched everything on, I was floored by the improvements I heard. Especially imaging. That quick session produced the best, most palpable imaging that my AR90's had ever produced, to that point. Very realistic. Holographic. I never knew the speakers had been capable of that type of performance. I've been chasing my tail, ever since, trying to improve that experience, when I should have left well-enough alone...!
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I recently found a pair of AR58S speakers, via Craigslist, at a very good price. The young millennial I bought the speakers from, was replacing them with Paradigm Studio 40 V2's. Unfortunately, the Paradigms were not hooked up, so I didn't get the opportunity to hear them. And hopefully, not unfortunately for the new owner, he hadn't heard his new speakers either. A friend had recommended them, and said they were better than his AR's. The millennial took him for his word, which allowed me to be the happy new owner of the 58S's...!
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6 hours ago, ka7niq said:
Yes, a pair of either the AR 9's, or the AR 90's , with enough power, will literally rattle the room !
But you need a powerful amp, and one that will not crap out, into 4 ohms.
The Paradigm's are designed for uniform off axis dispersion. The AR 90's not so much. Their dome midrange driver plays down to 200 hz, and clear up to 7000 hz, before the big dome hands off to the small tweeter. This wreaks havoc with the off axis dispersion. The guy I sold my old AR 90's to re designed his crossovers, to cut that big dome off sooner by dropping the crossover point from 7000 hz down to 3000 hz. This greatly improved the off axis dispersion, and the tweeter had no problem going down to 3000 hz either.
Perhaps stay with the Paradigm's, and satisfy your craving for Bass with a good Subwoofer ? SVS, Hsu, Velodyne, and Outlaw all make fine affordable subwoofers, to name a few.
Th AR90 and AR9 both ran the UMR dome from 1200Hz to 7KHz. Only the LMR driver responded to the woofer crossover frequency of 200Hz.
Specifications
Type: 4 way, 5 driver loudspeaker system
Frequency Response: 23Hz to 30kHz
Power Handling: 250W
Recommended Amplifier: 50 to 300W
Crossover Frequency: 200, 1200, 7000Hz
Impedance: 4Ω
Sensitivity: 87dB
Bass: 2 x 250mm acoustic suspension
Midbass: 1 x 200mm acoustic suspension
Midrange: 1 x 38mm hemispherical dome
Tweeter: 1 x 19mm hemispherical dome
Dimensions: 1102 x 368 x 386mm
Weight: 37kg
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Larry and I mentioned several different AR speakers, which could be used in your 9's. Also, there are 4 AR94Si woofer-midrange drivers (none mine) on eBay. They would probably work too. But, I'd first email the seller, and confirm the impedance is the correct 4.5 Ohms.
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2 hours ago, lARrybody said:
The only 8 in. AR woofers with 8 mounting holes I have ever ran across are the 200001-1 woofer used in the AR 18, 17, 15 and 25. They all have smooth cones and foam surrounds.
The 200027 LMR, for the 9's, 90's, and 94's, had 8 mounting holes as well. That makes me wonder if all these woofers were built on a common frame, with like parts? Even the impedance of my 90 and 18 drivers match. Which makes me think that these various woofers can substitute for one another, in a pinch?
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It looks as if the drivers were rebuilt by a decent shop. Even though they didn't rebuild to stock. So, if the speakers work, and you like the way they currently sound, I'd leave the speakers as-is. It would cost close to $600 or more, to source the correct woofers. So, I'd enjoy them, without any guilt, because you still have a fine set of speakers.
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I always thought the MGC-1's used the AR48, AR58, AR-1MS 4" midwoofer? At least from pictures, they look the same.
I miss Brian, really I do. 
8" LMR for AR-9 and AR-90 - 200027 - Availability/Substitutes
in Acoustic Research
Posted
Did you find a nice improvement in sound, with the correct LMR driver? Care to share details about what differences were heard? Also, was the 210045 poly cone better in any area? Just curious.
Thanks.