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ra.ra

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About ra.ra

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  1. 3a, LST & LST-2 tweeters

    Thanks for the pic and brief summary, Glenn and Chris. Those LST's look fantastic and that whole test rig looks like a fun experience. I think I spy some nice EPI's on the floor there, too.
  2. Filled Fillet Foam on AR-9 8" LMW

    Thanks, David, for digging up the correct part drawing - - interesting to note that this is one of those double dust cap woofers. I recall that we discussed this issue not too long ago - - I've been curious about this, too - - and there are several 6" and 8" woofers that include this "treatment". Attached pic shows this bead of goo on an 8" Tonegen replacement woofer from an AR-7. In the previous thread, I initially described this substance as feeling like silicone, but David more correctly likened it to rubber cement, and it does feel very much like that. And, only on the driver parts drawings that include this treatment can the note be found which requires minimum 16 hours cure time prior to testing, so I suppose this does specifically refer to this rubberized treatment. However, as soon as you begin to assume that this substance was applied at the interface between the cone and the foam roll to create similar effects that the filled fillet achieves, just then a very different application appears. The 8" woofer part no. 200037, found in the AR-18s and 28s and 18B models (see detail attached), shows this substance (process spec. #104010) applied to the underside of this same cone-surround interface. Now its purpose becomes something of a mystery - - to me, at least. Stimpy, in the drawing you commented on for the 027 woofer, note 11 does refer to this treatment, but in the section drawing, item 11 simply refers to the inner dust cap mentioned in the parts list. The nomenclature may be a bit confusing, but these items are not related.
  3. 1965 High Fidelity AR-4 review

    Am just posting this again for posterity. While the existence of reviews and advertisements for the AR-4 has already been documented, this might just be the first time I have ever seen any company-produced product literature for this particular speaker model. I have seen earlier AR lit from prior to the AR-4's introduction, and also subsequent similar-looking pages for the brand new AR-4x, circa ±1965. Many of you, I'm sure, have probably seen this brochure, but I suspect it is rare simply because the AR-4 was only in the product line-up for about one year or so. I particularly like the part that says "...the highest quality per dollar." Also noteworthy is the advice for unfinished pine cabinets: "not suitable for staining".
  4. AR-18s speakers

    Yeah, this seems to work fine for keeping these tinsel wires "protected" along the surface of the baffle board, but the tape wouldn't be practical on the cone surface. I may just try something that I have on hand that can be applied with precision - - maybe simple water-based white glue (Aleene's) that dries clear will be sufficient here.
  5. Intro

    This is mostly a matter of the non-comparable number of loudspeaker units produced by the two companies, I would say. Many of those Allison models are absolutely terrific audio speakers, and tho' I have yet to own a pair, I enjoy learning from those members like yourself that have deep knowledge and passion for this line of products.
  6. AR3/AR3a guidance needed

    That grille does appear to be in exceptional condition, and like yourself, I very much like the linen and walnut combination look of the classic AR's. However, the weave and texture of the AR-3 fabric really does account for its unique appearance, and over time, I think you may begin to appreciate its distinctive visual characteristics, particularly if you have the correct badges to give it the "full Cleveland". Not a bad price at all, but since I also acquired my first AR's while living in Indiana in the early 70's, I would have tried to talk the guy down to $75 to cash in on a friendly Hoosier discount. This is such an important point that you might even want to begin long-term planning to eventually replace the original mid in speaker #2 as its performance continues to diminish. This process, of course, would require the addition of the 6uF cap and 0.4 mh coil into speaker 2 at that point. Regarding new cap, there's no reason a locally purchased 6uF NPE won't work fine, but since you're already using new poly types, it might be nice to complete the mid circuit with poly caps. But yes, paying add't shipping for a single cap order is ridiculous , so perhaps someone here has an unused spare cap in their parts bin that could be mailed in a simple envelope. I'll try to look through my stash in the next day or so.
  7. AR3/AR3a guidance needed

    HI Bruce, those look like fantastic speakers. My guess at what's going on is pretty much explained by this document which outlines the history of the AR-3 crossover. Based on your serial numbers, I suspect both speakers originally had the single coil x-o shown in Part C. At some point the midrange in speaker 1 went bad and was replaced with an AR-3a midrange (due to lack of original AR-3 mids) and the two crossover revisions shown in Part D: addition of 6uF cap and a second coil, as confirmed by your pics. Looking at the variety of drivers shown in the 3a restoration manual, I think your speaker #2 mid is the A.9 version; and the mid in #1 appears to be the A.13 or A.14 variety. Replacing caps is probably a very good idea, but you should not neglect making the effort to examine, evaluate, and restore or replace the variable level controls for the mids and tweeters. This is every bit as important as having accurate caps for the proper HF performance. One thing of interest is the addition of the triangular corner panels and the Velcro tabs, to facilitate future grille removal, I presume. It is quite possible that this was done at the same time that the mid in speaker 1 was replaced, since these corner pieces were not original features. They appear to have been installed very well, but I am curious whether this results in the grille fabric sitting further forward than originally intended?
  8. Smaller Advent woofer

    If I am able to furnish any of this, I will try. Let me try to find that over-baked woofer first.
  9. Smaller Advent woofer

    That's about as far as I can go, so anything more specific regarding voltage and I am clearly unqualified, and I suspect most of the weekend hobbyists like myself are in the same boat. I like this statement, too. Pete. We know there are always varying degrees of quality in most any sort of goods produced at any time, and as soon as I wrote my not-fully-informed defense on behalf of more modern caps, I thought to myself, "but I so often prefer the quality of older things over their contemporary replacements". Compulytics I am willing to try to salvage - - - black/red Callins-Temples maybe not so much - - in fact, never.
  10. Where to find 10" Bass Drivers for AR9LS

    Wow, what a great point, how did we omit that crucial part of this discussion? On axis?..... not applicable. Off axis?....not really applicable either. It seems to me that the sound emitted from this 10" driver rumbles around in a tight padded chamber before it leaks out near the floor line to somehow fill in the spectrum with its assigned frequencies. This is by no means a suggestion that this driver is of marginal importance - - in fact, it is vital - - but it appears to perform more like a typical subwoofer than any other front-facing LF driver more normally seen in AR speakers up to this date of manufacture.
  11. Smaller Advent woofer

    Thanks, Pete, great advice, and despite my devil's advocate position that one does not always need to automatically replace NPE's with film capacitors, I will most likely follow the practice you have outlined: when replacing low uF value caps, use some variety of film cap. I am surely not enough of an engineer to comprehend or challenge your comment about sustained voltage , but it certainly sounds like a well-informed conviction based on substantial experience. However, I am unprepared to buy into the popular notion that all NPE's have a very limited lifespan - - caps are surely manufactured to higher standards these days, yet many of us have documented 45 year-old Sprague Compulytics that measure and perform just fine, and they also have an obvious robust build quality to enhance this confidence. I have no doubt whatsoever that some electrolytics are showing their age, drifting from spec value, and affecting the speaker performance after little more than a decade of use, but I do tend to recoil a bit in disagreement when blanket statements are blindly stated over and over and......well, you get my point.....which enhance the oversimplified and oft-repeated line which suggests: 'lytics are bad, films are good.
  12. Where to find 10" Bass Drivers for AR9LS

    Apologies for overlooking this earlier comment, but I'd agree that you are correct with this statement, and Robert_S is always on top of these details. The AR-925 is identical to the AR-92, but revised for the Euro market, and does not include the MF and HF switches. Similarly, the AR-915 (Euro) and AR-91 (U.S.). I'd say that any variety of the 033 woofer is probably suitable here.
  13. Where to find 10" Bass Drivers for AR9LS

    Roy, I was curious about this, too, and while I found some online discussion that the 9LS used the same 10" woofer found in the AR-14 and AR-48, I am pretty sure that statement is incorrect - - those models use the XXX040 woofer. At least one other model that used the 033 woofer, I believe, is the AR-92. I just wanted to comment on the interesting style of this cabinet construction. Not only is that bottom void chamber for the down-facing 10" woofer rather unique (it was lined with foam, yes?), but the "look" of a front box sliding inside a slightly larger rear box was a very conscious visual decision that definitely had cost implications. And while the 9LS had the black front with red text, I think the 9LSi (improved) presented a veneered front face without the graphics.
  14. Where to find 10" Bass Drivers for AR9LS

    Stimpy's post shows the "improved" schematic. The schematic of the original 9LS differs in a few areas, but also has woofers wired in parallel within the same chamber. The only driver with its own separate chamber is the lower midrange. The full AR drawing has additional dimensional info.
  15. AR-18s speakers

    Just wanted to include these images along with this thread - - these online pics show the AR-18LS, which I believe is Euro version identical to AR-18B, except for exterior cosmetics: cabinet styling, grille detail, rear terminals, etc. What I would expect to see is shown in first pic: square edge cabinet, vinyl wrapper, tweeter 034 with screen cover (shown next to little AR-8LS). Second pic shows a mild variation, with what appears to be the uncovered 038 tweeter and possibly a curious black stained pine cabinet? But I wanted to ask about the close-up tweeter pic that was part of this web link. It appears that the tiny tinsel wire leads are still connected to provide continuity, but clearly they have been dislodged from their original positions, as shown by the S-shape glue shadows. It is not at all uncommon to find these wires askew in an unintended position, but they are so fragile that they really should be affixed to the paper cone. Original documents show this adhesive named as Hapco 549-D - - - what would be a suitable type of glue to re-attach any loose wires on this type of tweeter?
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