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AR55

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  1. The culprit may simply be a dirty switch. Try cleaning the switch with DeoxIT, and see that clears it up. My daughter's vintage Pioneer integrated amp was occasionally producing a crackling sound, and it turned out it was a dirty toggle switch. Sorry, I missed that Aadams already gave this advice,
  2. AR55

    AR98ls

    In addition to reversing the tweeter polarity and adding 1.5 ohm & 2.5 ohm resisters, I believe that the 98Lsi crossover also deleted a 5uF capacitor that the 98Ls crossover had between the tweeter and the 3uF capacitor & 0.080mH coil. Attached are copies of the 98Ls crossover schematic, the 98Lsi crossover schematic and a markup of the conversion of the 98Ls crossover to a 98Lsi crossover (note that the yellow & blue wires were reversed between the 98Ls & 98Lsi):
  3. They may very well be stapled. I have my wife's uncle's AR2 and the grill on that speaker was glued in place like the 2ax he also left with us. My nephew happens to have my dad's AR2's. I just checked with him, and he tells me that his grills are held in place with small staples. It looks like your best bet is to check for staples first.
  4. They are probably glued. Paragraph 2.3 Removing the Grill in the "Restoring the AR-3a" writeup describes a couple of options for removing the grills. I used the drywall screw option and was able to pop the grills off without damaging them. See link below or get to it from Featured Items on the Classic Speaker Pages homepage. www.classicspeakerpages.net/library/acoustic_research/original_models_1954-1974/original_models_schematicss/restoring_the_ar-3a/restoring_the_ar-3a_full_pd.pdf
  5. AR55

    ar38s woofer

    The 200040, 10" woofer used in the 38s, 48s, 48b, 30, 48bx & 48bxi has a voice coil DC resistance rating of 6.5 ohms +/- 10%. The 200004, 10" woofer used in the 2ax (later version), 8 (ADD version),12 & 14 has the same 6.5 ohm resistance, so I think that this would be a better match for the 200040 then the 200033. In addition to checking eBay & other sources for the woofers by the 200040 and 200004 driver numbers, I would suggest that you also search by the speaker model number. Many times when speakers are parted out, the listing will only state the speaker model number and not include the driver number.
  6. The 9Lsi's retailed for $1,950 a pair in 1986, which is less than $7500 in today's money. I have never auditioned a pair of speakers that retail for less than $10k that I felt were better than my 9Lsi's. The Martin Logan Renaissance ESL 15A and the Revel Ultima Salon 2 retail for $20k to $25K. When I listened to them, I felt that they both had a comparable bass response to my 9Lsi's and more detailed, particularly in the midrange. Did I compare them side-by-side with my 9Lsi's? No, I didn't. If I had, I may not have reached the same conclusion.
  7. I attended a guest lecture given by Paul Klipsch back when I was in college. He was in his seventies by then. He started out his lecture with an impressive discussion of the engineering principles of the folded horn in the Klipschhorn. Then after a brief discussion of the design of Klipsch’s other speakers, his lecture took a bizarre turn. He went into a near tirade bashing acoustic suspension, Edgar Villchur, AR and Advent. He came across as a bitter old man that was envious of AR’s and Advent’s success. His and others inference that Edgar Villchur was unqualified because he did not have an engineering degree is ludicrous. Many significant inventions have been created by individuals who lacked a college degree in their chosen field. Let’s not forget that a couple brothers with no formal engineering training went from manufacturing bicycles to inventing the airplane. Villchur, like the Wright Brothers, was not only extremely creative, but he was obsessed with solving something that alluded others. He researched their work, attended pertinent engineering lectures and experimented religiously until he perfected his inventions. Now, are there speakers that have surpassed my AR-11’s? My AR-98Lsi’s? My AR-9Lsi’s? Of course there are. I have auditioned a few of them, but I can guarantee that the Harbeth Monitor 30.2 and many of the other extremely overpriced speakers praised by Stereophile are not in that group.
  8. I own the 9Lsi, but I never had the opportunity to listen to the 9LS. I can say with some certainty, though, that the 9LSi is the better speaker. This is based on comparative listening of the 98LS and 98LSi, which has the same crossover upgrade as the 9LSi. You can hear a slight harshness/brightness in the upper midrange of the 98LS that is not present in the 98LSi or the 9LSi. Now the bigger question. Is the 9LSi a better speaker than the 9? Hard to say. I’ve never directly compared the two. I listened to the 9 in a dealer’s showroom years ago and felt at that time it was the best speaker on the market. Of course I wanted it, but I was a college kid and naturally I couldn’t afford it. Years later I luckily acquired a pair of 9LSi’s from a guy’s uncle that was downsizing. To me its sound is on par with my memories of the 9 and is more forgiving in its placement. I have never felt that my 9LSi’s needed tweeter or midrange controls. My listening room seems to be well suited for the speakers. That said, even though my hearing still reaches 12,000 hertz it’s down more than a few db at the high end, so last year I did what some would deem sacrilege. I boosted the treble control on my preamp 4db. It sounds right to me, but my 32 year old daughter, who owns my original 98LS’, thinks that they are way too bright now. I probably would when I was 32 also.
  9. Pascal, If you can't find an original pair, you may want to consider having a small steel fabricator make a set for you. Below are a couple of pdf's of sketches that I prepared for the fabricator based on the original frames. In the picture below the stand in the middle is original and the ones on the right and left are custom made. I paid the fab shop $125 US to make the pair about 5 years ago, which isn't too bad considering I paid $40/pair for the originals back in 1979. AR-11 Stands Dimensions.pdf AR-11 Stands Isometric.pdf
  10. I not sure opening up the dual dome assembly is a good idea. The lead wires from the tweeter are not just soldered to the tabs that are screwed into the face plate. They are also glued in place. Removing the cover plate could easily break the leads.
  11. I have never found an answer to that question. I replaced the foam in my 9Lsi's base chamber about 10 years ago. The porosity of the foam that I used is definitely not fine - probably close to 30 PPI. I feel that my speakers' base response is deep and clean, so I think that I guessed correctly. If you are interested, Vintage-AR (eBay) sells a foam chamber precut kit for a rather pricey $100. I don't know, however, if their foam is any closer to the original AR spec then what I used.
  12. Attached is the booklet that came with my AR-98Ls'. Recommendations for speaker placement are provided on page 3. I have listened to them placed on the floor and on 12" tall stands. Personally I think that they sound best when placed on the stands. AR-98Ls_Instructions_for_Installation_and_Use.pdf
  13. The 8" lower midrange (200045/210045) for the AR-9Ls, 9Lsi, 98Ls & 98Lsi may also be worth considering as a substitution for the 200001. The spec for the 200001 calls for a measured DC resistance of 5.0 ohms +/- 10%. I measured the resistance of spares I have of both 200045 and the 210045 and they all fell between 4.6 ohms and 4.8 ohms, which falls within the 200001 spec.
  14. Something else to keep in mind when storing drivers is moisture. Excess moisture can be a big contributor to the deterioration of spiders, cones, surrounds, etc. I live in North Florida where during much of the year the outside humidity is over 80%. Even though I store my spare drivers in a conditioned room and have the HVAC system set to keep the inside humidity below 60%, I still place a small silica gel pack in the box.
  15. AR advertising booklet with excerpts of reviews of the AR-10pi, 11, 12, 14, 15, 17 & 18. AR_ADD_Series_The_Critics_Choice_Around_the_World.pdf
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