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Mexicomike

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About Mexicomike

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    Mexico City/Chester, MD
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    Too many to list but include...<br />Audiophile since I was around 14 - first amp was an Eico 4WPC kit!<br />Build Harpsichords<br />Photography<br />Play Flamenco Guitar/piano/started learning violin 2 years ago.<br />Built/owned/operated small recording studio for 10 years <br />Motorcycles - raced in my 20's; still own a Norton Commando I raced...<br />Built auto high performance and competition engines; still do it for friends<br /><br />

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  1. Mexicomike

    who?

    I used microstatics with my 3As and liked them quite a bit back in the day. I can't see much use for them with LSTs but have to admit I've never tried them...
  2. Mexicomike

    Driving AR-303a speakers

    " do recall some of the design info on the 303 indicating that it was a few dB less efficient than the 3a." I didn't realize ANYTHING was less efficient than a 3a!
  3. Mexicomike

    AR 9 Power ?

    When I said a Sansui rated at 120WPC that was tested as around 50 RMS, the 120 WPC rating was listed as IHF. I don't think that they listed RMS at all but perhaps they did and I don't recall it. This was in 1970. As you noted, for sure they did later, as required by US law. In fact, the legislation requiring an RMS spec was a direct result of the influx of Japanese equipment during the Vietnam era using the IHF rating which made those amps appear more powerful - and therefore a better cost per watt deal - than US amps. Prior to that time, the only separate amplifiers around in the US were from fairly well-known US manufacturers and "Continuous power" ratings were part of their specs so there really wasn't an issue. Typically, the wording was something like "100 WPC IHF music power or 50WPC continuous." What used to be called "continuous" evolved into "RMS" though personally I think "continuous power" is actually a more meaningful term in real life.
  4. Mexicomike

    AR3a Guidance/Advice

    Just curious, what is the purpose of the pair of wire-wound resistors? Their are (were) none in my AR3As which had all the original Xover parts/caps in place when I disassembled them.
  5. Mexicomike

    AR3a Guidance/Advice

  6. Mexicomike

    AR 9 Power ?

    In reality it's probably not much of an issue because I suspect that most folks don't drive these 40+ year old speakers the way we (or at least some of us) did when they were new. For one thing, most folks don't listen to music in the same way we did back then. We used to get together JUST to crank up the volume to "realistic" levels and sit and listen to a new album (or two) by whoever. I don't think that happens much now. And, of course, I'm sure some folks don't care to drive them to those levels just because of their age. 99% of the time they are on, my LSTs are probably hardly aware they are producing any sound - they mostly just get the input from the computer and Itunes and provide background music. On rare occasions I'll put a CD on the CD player and crank it up a bit and on even rarer occasions, I'll put on some vinyl and listen like we used to. On those days, the LSTs and the McIntosh power amp get to do what they really can do but I'll bet I don't do that 10 times a year. My 3A's are now the TV's external speakers, powered by an AR amp. So, they don't get worked very hard at all either.
  7. Mexicomike

    AR 9 Power ?

    I did not suggest they were unstable; they were fine if used within their limits. It's just that in general their actual RMS power limits (as opposed to their advertised IHF ratings) were well below what AR3As were (are) at their best with. I still recall testing one of the Sansui's - I can't recall the model number - that was rated at 120WPC but when tested at Bill Case Sound in San Antonio, TX, it was putting out around 50WPC RMS. OTOH, I would assume that if they had amps in the 300wpc IHF category, one would assume they could manage at least 100 WPC RMS and they would probably be fine with 3As. But it's important to remember that 3As (and 2Axs) were well known for tweeters burning out when driven hard. We thought they were fragile but we learned later that the bigger the amp, the less likely you were to damage a tweeter because there was sufficient power to avoid going into clipping and clipping is what burnt out the tweeters. IMO, if you want to drive an AR3A to the kind of listening levels it was designed to produce in a decent sized listening room, 200WPC RMS (or more) is a good place to be. But if you are just going to listen to it for general pop music at background or slightly higher levels, you could probably get by with 20WPC. As I said earlier, the power meters on my McIntosh amp seldom got above 3WPC with the 3As when used that way.
  8. Mexicomike

    AR 9 Power ?

    As I said earlier, a LOT of them were sold - frequently bundled with speakers of the same brand. They were fine for what they were but they were nowhere near the capability or the stability of the US-made amplifiers in the 100+WPC range AT THAT TIME. I blew out tweeters on AR 2AXs and AR3As back in the day with amps like the Sansui and Pioneer amps due to insufficient RMS power (all totally covered by AR's superb 5 year warranty). Never blew another tweeter after switching to a PL400 in 1972. Obviously, if you listen at moderate levels it's not really an issue. My 3As at comfortable background music level drew around 3 WPC. BUT if you put a recording like the Telarc 1812 Overture recording and set the volume at the beginning at a comfortable listening level, the cannon shots at the end will cause my 270WPC McIntosh amp to activate it's "Powerguard" anti-clipping circuit. And the cannon shots are not ALL THAT LOUD. Once an amp goes into clipping, it can fry tweeters quite quickly.
  9. Mexicomike

    AR3a Guidance/Advice

    Replace all the caps. There is no reason to fool around with leaving any of the originals in the circuit. I thought my 3As sounded fine with the original caps but when I recapped one of them and A/Bd the two speakers, there was an obvious difference in clarity and realism. Cap testers do not simulate the load in the circuit and therefore, especially with an old cap, what the meter says the capacitance is and what actually happens in the circuit can be quite different. I would retain the original pots. The pitting wont hurt anything and if you use dielectric grease, as others have advised, they will work perfectly with no issue at all. Same is true of the speaker connectors - also as others have advised, leave them as is and put an appropriate connector on the speaker cable. After all that it's just a matter of hooking up a good amp and off you go!
  10. Mexicomike

    AR 9 Power ?

    I know this may annoy folks but as an audiophile of that era...Japanese amplifiers/receivers were not considered particularly good. They were widely available and used because of the large number of servicemen/women who served in Vietnam era and the PXs (here and overseas) carried mostly japanese products of that type and the few American products carried were considerably more expensive. A suitable amp for LSTs from back then would have been something like one of the Phase Linears, a McIntosh, Crown, etc. The serious AR crowd (of which I was one) would never have powered a 3A or an LST with a Japanese amp. Tests from back in the day repeatedly demonstrated their lack of capability compared to the (more expensive) US amps and the common use of IHF power ratings instead of RMS. I am referring to amps made in the AR era - call it from around 1960 to say 1980 - I am not referring to Japanese amps that came later.
  11. Mexicomike

    Acoustic Research LST-2 Speakers

    Since you have to go in there anyway, I'd replace the caps. I thought my 3As sounded fine as well when I got them. I didn't plan on replacing the caps but I decided to do so and the new ones made a quite obvious difference in clarity. I suspect if you recap one of the speakers and a/b it to the other, before you recap it, you will be surprised at the difference.
  12. Mexicomike

    AR5 new cabinets

    "A Prince among speakers. " Indeed!
  13. Mexicomike

    AR5 new cabinets

    So...are you trying to find speaker badges that say "Speaker Formerly Known as AR5?"
  14. Mexicomike

    AR 2ax serial numbers

    As far as I know, no 3-way/3-driver AR speakers of the classic era (up to/including the LST) were book-matched. The LST was the first 3-way AR speaker that might be said to be bookmatched though there was never a performance or benefit claim re that for the speaker. I think it is "bookmatched" just because it was logical to build it that way, not because there is any real sonic advantage to it.
  15. Mexicomike

    AR3a - pushed in speaker cone nightmare!

    A dust cap is meaningless from a performance point of view. If that's what you are talking about on the woofer, sure, I'd try to "fix" it but it actually doesn't matter. And since these drivers were never intended to be seen, I wouldn't worry too much about it. If a tweeter dome has been dented - that might be a different story. Though I have read opinions that it actually doesn't really affect the sound. Seems to me it would have to at least affect dispersion though whether anyone could really hear it, I don't know.
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