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rl1856

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  1. I am referring to the tweeter shown in picture #28 on page 33 of the AR3a restoration guide. Thank you.
  2. I do not have a supply, but know of a pair that is available.
  3. I understand the 211003-1 tweeter is from the KK designed AR303 series. However I find few references to this tweeter in forum archives, and one reference on the last page of the AR3a restoration guide. I re-read the Stereophile review of the AR303. Overall FR sloped downward, with treble response noticeably less than MR response. However, treble dispersion was reasonable, holding up well to 10khz at 45-50' off access. Subjective comments noted that in room dispersion somewhat compensated for the declining on-axis response slope. I would like to find the electrical characteristics of this tweeter; sensitivity, impedance, FR, dispersion characteristics and of course opinions from those who have experience with this tweeter. Thank you !
  4. A single Dynaco MK-2 or MK-3 would be a near perfect pairing for your speaker and intended use. MAC 60 or EICO HF50/60 may be better, but are considerably more expensive. A Dynaco MK-2 or 3 is relatively cheap, and easy to restore. It will deliver 50-60w of clean power, and is the amp used by AR for demonstration of the AR1, AR1W and AR3. One of these days Ill get around to restoring my Janszen Z400 and Z350 speakers....Each is a 10inch woofers with a pr of electrostatic panels. Good Luck.
  5. OK then- a drop in for the AR9-10-11-12 series, but requires a coil to match an AR3a (and presumably an AR5). Has anyone measured on axis and off axis response ? Has anyone determined sensitivity ? Has anyone determined what size coil is needed for this tweeter to match the AR crossover ? Thank you.
  6. Is this dome tweeter truly a drop in replacement ? I searched the archives and saw references, but nothing definitive. Seller advertises the dome as a replacement for the 8ohm tweeter in the AR2ax, 5 and LST. https://www.ebay.com/itm/AR-Acoustic-Research-Replacement-8-ohm-Tweeter-AR-2ax-AR5-LST-2-MT-4121-8-/162689351715?hash=item25e10a8023 Is it drop in, or are crossover modifications required ? Thank you.
  7. I have read AD's content since the days of Listener Magazine. He has a specific preference window for audio equipment and reproduction: Class A SET driving horn loaded, or very efficient reflex loaded speakers. He also seems to be of independent spirit- he deliberately arrives at his conclusions. Over the years he has gained a reputation for being "vintage" friendly. I think many people have suggested he review this or that component, or investigate this or that technology. When he feels pushed in one direction, he often pushes back. A few years ago he wrote about his (limited) experience with a Marantz 8B. The unit was freshened by a few new caps, but was largely stock, meaning 55+yrs old. His comments were very much a case of damning with faint praise. Other times he brings up vintage alternatives that are outside his narrow window, and again his disdain is palpable. He often mentions issues/questions brought up by listeners, but are contrary to his opinions- again mostly damning with faint praise. Consider that Acoustic Suspension speakers represent a 180' shift from his beloved Altecs or Devore high efficiency speakers and require something completely different than a SET amp to drive them. In that light, his comments are almost predictable. AD is a senior editor of a high profile publication (within a niche hobby) thus it is regrettable that he sometimes reacts in this way. One would think he would either refrain from commenting, or have someone more open minded address the issues. It think it is unreasonable to expect a full suite of Pollyanna reviews, but is an open minded reviewer too much to ask for ?
  8. AD's opinions did not surprise me. He is opinionated, and has a specific preference when it comes to equipment. He just doesn't like anything that challenges his paradigm. What was troubling were the factual errors included in his prose. He stated that as efficiency goes down, distortion goes up and uses this "fact" to denigrate AS designs. Yet he does not address the crucial fact that AR (and most AS) designs have been universally praised for their low distortion deep bass. Distortion being notably lower than what is delivered by reflex designs, and bass which is deeper and cleaner than what a Khorn can deliver at equivalent frequencies. AD states that AR speakers were introduced at the dawn of high power transistor amps...forgetting that the AR 1 was introduced in 1954, about 10yrs before SS amps were market viable. He advances the notion that the science behind AS designs does not work. He then uses the fact that there are few true AS designs in the current marketplace as proof that the concept is flawed. Ken Kantor posted in this forum (in 2008 ?) that it was more expensive to produce a good AS speaker compared to a ported design, and that technology had advanced enough that ported designs could deliver similar performance from a smaller box. I posted about the inaccuracies to another forum that is frequented by SP authors. The editor's response was that AD has opinions and can say what he wants.
  9. I have direct experience in this area. I have a restored Fisher 400 and have used it for several years with AR speakers. A Fisher 400 will deliver about 20-22wpc throughout most of the audio band, slightly less in the deep bass. I have used the following speakers with my 400: Dynaco A25, Polk Monitor 7, Acoustic Energy Aegis One, ADS L410, AR 92. The best sounding speakers were the Polk Monitor 7 and the AR92. The AR92 is an updated version of the AR5....10 inch woofer, dome midrange and tweeter, 8ohm impedance, and somewhat greater sensitivity than the 2ax/5. I used this combo in the family room of our summer vacation house in a moderately large space. I completely enjoyed the sound. Great bass (as expected), clean and clear midrange and treble. I enjoyed the imaging when in the sweet spot. However- maximum volume was just above moderate. Anything more and the combo sounded compressed and harsh. Within limits, the AR92 sounded the best of all of the speakers I used, there was a synergy that was not present with other combinations and the sound always brought a smile to my face. My recommendation would depend on how you will use the combination. If for low to moderate level listening then you should enjoy the sound. If you expect this to be your "only" system, or if you expect high volume levels you will be disappointed. Make sure your Fisher 400 has been restored...new power supply, coupling capacitors and rectifier at least. Note that you or your tech will likely have to adjust resistor values around the rectifier to be sure the new rectifier does not provide too much voltage. You can purchase a restoration kit from Ebay, and it shouldn't take more than about 3hrs for a qualified tech to install and test all new parts. Expect to pay more if you also want the tuner section aligned, and the phono section checked to ensure that it provides correct RIAA compensation. If you are lucky your 400 includes original Fisher branded Telefunken 12ax7 tubes ! 7868 output tubes are easy to find and relatively inexpensive. Good Luck and keep us posted.
  10. Pair of AR9LS For Sale on a Facebook forum. $750 In Iowa, about 5hrs from Chicago. https://www.facebook.com/groups/1742722662620198/permalink/2542620959297027/?sale_post_id=2542620959297027 Not mine, and I have no relation to the seller.
  11. Article on the venerable and iconic AR-XA Turntable. But using a photo of a radically modified deck......
  12. I found the Sept 70 issue of Electronics World. Thank you. The AR3a was reviewed in by JH in the Jan 69 issue of the same publication. I have attached the relevant graph. Notice anything different between this curve, and the AR3a curve included in the graph at the top of this thread ?
  13. Another overpaid hack......irony of ironies is one of his reference speakers is a later version of the BBC LS3/5a....probably one of the most famous "box speakers with a dome tweeter".
  14. What if the issue was from the original curves JH created for the 3a ? Looking at the curves at the top of this post, both the 3a and 5 have about a 3db decrease centered at 2khz. What if his original measurement of the 3a did not have this dip, or if this dip was not as apparent ? A perfectly functioning 5 would in comparison exhibit the dip he described.... "These curves were made by Julian for EW magazine and published, although it’s not clear if these are the actual curves made for the test reports or whether these are additional curves made at some later date, just for interest’s sake." Different curves, recorded at different times *could* account for the differences cited. Note that JH said he measured 2 sets of "5", and found an identical dip. He did not specify having retested a 3a to verify previous measurements. Could be key. in what issue of EW did this graph appear ? Thanks !
  15. Compared to AR 3a/2ax/5, the original large Advent was cheaper. Had almost the same deep bass response. Sounded better with rock music. Could handle more power when playing rock music. Marketing was designed to appeal to a younger buyer. Advent hit a home run with their first product.
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