Giorgio AR

Wonderful speakers, greath photos...

Roy I love them both, certainly they don't sound the same, to my ears perhaps the 3/4 tweeter is more discreet, but well defined in the high harmonics (it almost disappears when listening, but does its job excellently), the early one is more "visible" , but defines the high harmonics similarly...what can I say? They are masterpieces born from brilliant minds, innovative in the 50s and then developed without changing the original philosophy.

Aah, good 12" floor AR speaker...I also own one pair!

I can't figure out if the lower speakers are AR92 or AR91... P.S. congratulations for the original foam grilles of the AR10 MK2

In this case, however, the measurements concern the next tweeter with a paper dome and greater dispersion, different efficiency compared to the previous tweeter Certainly the Pots allow a fine regulation of the mid and tw emission, allowing to find the best (or subjectively preferred) sound balance. Anyway Bill I have to offer you my sincere compliments on the work done, on the attached photo shoot, on your dexterity and technical ability... I love the old AR tweeters too and knowing that they can be brought back to optimum efficiency is wonderful news.

I also follow you on AK, I've seen your "works" (perhaps saying "masterpieces" is better) I appreciate your passion, dexterity and attention to detail...the attached photos are very useful, helpful and very demonstrative for us enthusiasts. My compliments on your wonderful restorations of our beloved Acoustic Research.

David, I also own the AR2ax, these from '72 (therefore woofer with foam surround and 3/4 tw), they don't give me the same listening pleasure... the mid is too present and difficult to adjust to balance it, moreover the older AR2a are more efficient and easily adjustable precisely in the double cone mids to obtain a balanced sound (again from my impressions). Currently the AR2a are stacked with a pair of Heathkit AS-2a (previously with a pair of AR2 and the stacking was already optimal with only the super tweeter of the AR2a!), the result is excellent. On the left the current combination, on the right the previous...

David If you want pre Teledyne speakers, you need to look for a pair of AR3...AR3a was born under Teledyne ownership! If you are patient I would recommend a pair of less expensive AR2a (full Alnico), I have a pair of '63's which I have been listening to for many years, they have been in daily use ever since!! In my opinion (I currently have 28 pairs of ARs and 10 are always available for listening) they are probably the AR speakers I am most fond of.

Hi Carl, happy to have given you the correct input, it's really a pity to throw away a tweeter for a "small" problem, I personally fixed 3 of them, 2 of which from the AR6...all working well for the next few years, but above all they are the originals, the next best thing to our beloved AR speakers. I'm posting the photos of the last AR6 tweeter that I saved... there are four good welds and the restoration of the connection cables to the contacts... the protective tape repositioned as originally; the tweeter is like new throughout. The glue used has yet to dry and become translucent... then the repair becomes indistinguishable!

Posted December 19, 2019 On left original AS-2a masonite panel This is what can be done with good will, a piece of grooves, an alternative saw!

Splendid cellar, and splendid content ... thanks for the advice on the photos, I have already removed attachments where old or unnecessary, but many photos must remain, they are part of the narrative and illustrate the steps described as integration well. I will remove others where not needed.

Good morning Tom, splendid "warehouse", from the number of cardboard boxes I feel a "slight envy", but an enormous pleasure for the conservation of a piece of history. I circled this instrument of yours which I think is used to produce energy (human propulsion) to air-condition and properly store part of your collection!! With this photo I have exhausted my quota of attachments!

Beautiful pair, complete with cardboard box and documentation! Congratulations on your "loot"...but I have to tell you that the tw with the small central dent can patiently be straightened and from the unfortunately blurry photos, I seem to see replacement Tonegen woofers (the detail that makes me think of replacement woofers is the dark ring on the outside of the suspension and the color of the paper of the cones). To find out which woofer you have you have to remove a woofer, the two woofers (AR and TNG) are easily recognizable...you can also find my thread on the subject of my speech.

Hello, before stating that your tweeters have failed, if I were you I would check first (with the help of a good magnifying glass) carefully the wires that carry the signal to the coil: it often causes oxidation, visible for a greenish color , these may have an interruption along the course of the cone (you have not specified the type of tweeter of your AR6) and flange... with a lot of patience and dexterity, they can be repaired by replacing the interrupted and oxidized section of cable. If the cables are ok, check the Aetna pots which always cause corrosion they can interrupt the signal (most of the time they are easily recoverable and here you can find the recovery solutions) or if they cannot be recovered you can find the correct NOS replacements at an enthusiast's price by great JKent. Finally check and if it is the case, replace the capacitors. If the tws are definitely dead, post a picture of yours to help you find the perfect pair!

The plates in question are the rectangular ones, followed by the first square ones, thin with only the AR inc logo painted (not to be treated with this method) I have seen numerous brass plates damaged due to inadequate treatment... the writings of these labels are deeply engraved in the brass with special red paint in various shades, different over the years and producing countries. Small tip for repainting if writing is needed: the first job to be done is in sequence, the brass can still remain oxidized, use a few drops of paint remover, after the reaction remove the residues, clean the area with "anti-fog" thinner, take a bottle of lady's nail polish of an appropriate shade, use of a brush of adequate size with soft bristles, subsequent brushstroke on the writing (you can easily overflow without worrying about it) ... after hardening and complete drying of the lacquer we move on to the brass surface, the writings return at the end... My solution is very simple: I use a perfectly smooth base (in my case a piece of a flat marble), a piece of water-based sandpaper of a suitable size is placed on top (600 grit, not less, but if needed you can use grit 400, followed by 600), a Teflon guide that facilitates sliding, two or three fingers pressing the plate and then we start with an oscillatory movement, sliding on the guide until we obtain the desired result, then rinsing with distilled water ... we return on the previous writings. lacquered, after the passages with the abrasive paper all the excess lacquer is removed leaving the underlying perfectly written. renewed... if minimal defects remain, place a cotton rag (single or double layer) under the abrasive paper, go over again with less pressure and finish as above. Personally I don't varnish the surface, but it is feasible, originally the plates could only be in brushed brass but also lacquered ... as desired. Under the usual explanatory photographic kit. Pair of AR3a plates before (they weren't the worst, but they are the only ones I can insert)... below others: the AR2ax, the 2AR4xa are untreated, good and remain so, the single AR7 below retains the protective nylon veil and remains thus together with its sister (it belongs to the pair of late AR7s that will not be restored and kept like this!) ... ...so I renewed the plates...with makeshift means at no cost

From my experience and from the photo you posted, the brass under the protective cover did its job well, except for the small top corner... I'd leave it at that. If you remove the cover, the writings are not damaged, but (they are painted, but the engraving of the same prevents damage) residues and opacity of the adhesive on the cover remain... difficult to remove except physically* or chemically (with this alternative, easily alter or melt the paint of the lettering). To help you, I am attaching a link to an Italian site of which I am a member (use Google translate to translate the explanatory text on my badge renewal technique!), if you want to skip the irrelevant one the part dealing with badges is almost at the end However, I am attaching only one photo (I have almost exhausted the possibility of inserting photos here where you can see some renewed badges with others preserved: AR2ax and pair of ARxa, and one in particular of AR7 below which I voluntarily leave original with plastic cover!. Link... https://melius.club/topic/11755-acoustic-research-facciamo-chiarezza/page/2/#comments * Physically...the satin finish of the badges is horizontal!!, with my simple advice, the final aesthetic effect is like new, also like the final surface processing!

Hi Lars, dear Swedish friend, congratulations on your purchase of the AR LST pair, you were right to follow your instincts...and many kilometers traveled by car to take them to their new home. From the photos, nothing serious: the woofer on the left seems to have an incorrect but efficient foam (this speaker can therefore be tested for functioning), the one on the right presents to my view an original foam that has now deteriorated (well, it means that this will be the first refoaming it receives). The tweeters seem to be replacements made years ago, probably by an AR laboratory: the one in the photo (and I suppose the others too has n° 200013-2 and should be original late spare parts at 8 ohms, adapted with the resistance and further capacitor to operate at 4 ohms of the AR LST. You don't have the wax and paper capacitors inside the cabinets that always fail, so if these AR LSTs were mine with only the change of the foams, check of the contacts only and seal tightening of all 18 speakers, and following listening session ... then if something doesn't satisfy you (but I doubt it!) you can do a job after the crossover by replacing any capacitors out of tolerance. I wish you good listening, you will also be able to make a report on the behavior of the tweeters, thanks to the "spectral balance" you can intervene on the emission of the tw and mid and adjust the medium/high range according to the environment and personal taste. You will see that Frankmarsi will also emerge who has a lot of experience with AR LST replacement and replacement tweeters, and it will also be interesting to know the pair sound of AR LST with 8 tweeters of the 200013 series! Attached a photo of my AR LST just arrived home... all good, but the woofers had a lot of glue and other material on top of the foam, masonite and cone, it was hard work, but the final effect is perfect, then I replaced only the paper and wax capacitors in my pair's cabinets... now I've been enjoying them for almost two years, perfect!

You Need a spectral switch for a AR LST speaker...? You have a AR-3f speaker...? Photo? A specific answer...

Kent, you are a great, great man, Always available in advice ( you have a great experience) and always attentive ti the needs of US fans, a big hug, Giorgio

I usually use a Ming Da MC-7R with AR91... perfect sound, but very great in clarity all low frequences, same in use with AR3a and AR LST. Tubes top in preamp.: 2 x 12AX7 Telefunken, 2 x 12AU7 Philips, 1 x 5AR4 Mullard, makes greath upgraded!

Hi Luxman, the upper or lower wiring shouldn't change anything in the sound between the two versions, basically apart from the electrical connection (and clearly the modification of the flange for the lower passage of the contacts) the two tweeters are the same, interesting the link introduced by AR55 with the link below: Regarding the woofer as declared by Acoustic Research, the 200001-1 one is called "universal" and offered as a replacement after the mid-70s as 8" woofer, it should maintain the family feeling therefore very similar to the previous ones with Alnico magnet, light paper cone and suspension in treated canvas, perhaps slightly different in sensitivity (here people more technically competent than me will be able to intervene), the problem may be finding the correct foam for compliance, roll diameter and other measures (no China !!), I rely on Larry, of "Vintage AR", but in the USA you will find and will be able to recommend other sellers with equally good foam. Finally, the AR4xa early woofers are often found on sale in the USA so with a little patience you can find a replacement for a better coupling of the two speakers ... to date if I remember correctly I had seen three at auction. Below you have several photos of 8" woofers and comments

Bravo Kent! You have successfully restored your original pair of AR4x over fifty years now ... and you have an additional pair of cabinets that enhances the Avid components, you could also stack them, maybe horizontally and tell us the final result (I think great). I really like the rear label identifying the model, components and modifications, all of which allows the eventual restoration of another pair of AR4x. Giorgio.

Giovanni I ask you if by eliminating the 1 ohm and 22 watt resistance on the woofer (already performed by an Italian technical laboratory on the AR78LS with excellent results, also confirmed by instrumental measurements), the low frequency performance, which many have declared lower precisely in AR91 and AR58S, I am attaching the link of the restoration and crossover modifications of the AR78LS. http://www.fletcherandmunson.it/wp-content/uploads/AR_mod_78_LS.pdf I'm sorry for the text in Italian, but the diagrams (with changes) and measurements taken should also be understood by fans of different languages !! Personally, among my pairs of AR speakers I have a pair of AR58S that have been working for years now and I will replace the crossover with that of AR91, a pair of AR91s and a pair of AR98LS, to all these AR speakers I would remove the aforementioned resistance and change the crossover of AR78LS as shown in the PDF. Thanks for your opinion. Giorgio

Hi Luxman, your AR4xa have different cabinets in the front baffle (in the second, it is recognized late due to the lack of the masonite supporting the external contacts for the tweeter) ... it can happen in the combinations of the cabinets made by AR. From information gathered over the years, it is certain the white paint on request in the 70s, certainly also in the AR3a, as well as the black paint job, also on request (the immaculate rear label and the masonite of the crossover without paint burrs pushes you to think about an original painting). In the late models of AR4xa, the woofer was with ceramic magnet and foam suspension, therefore compatible with the 200001-1 woofer (referred to in the price lists as "universal 8" woofer and offered as a spare for AR4xa) ... I hope you also have 4 original screws for fix the woofer 200001-1 correctly, otherwise you have to find 4 on the web! Finally, the frames of the grilles are original, but not the canvas, offered in classic linen, various versions and textures slightly different over the years and in the states where assembled or a thicker wire material in brown color optional, your pair should be made in Holland, as seen from the abbreviation HFX (the letter H indicates Holland). Finally, it would be nice to buy a couple of brass labels indicating the model to be placed on the bottom right of the grilles (currently there are some for sale on the famous auction site). Giorgio.

Bravo Giovanni, you have correctly disassembled the cone and its spider and you have brought back a 200003 woofer in perfect conditions of use ... really a great job, the owner of these AR10 / 11s that you have brought back in full working order will be satisfied!