Chris1this1

How about a tried and tested active driver for one of these? One that fits the depth and clearance constraints of the box and amp board, as well as the correct super low impedance to harness the full power out of the amp . I have repaired more than a few amps on the mk2’s, mk4’s and super juniors, but by now, many of their active driver surrounds and spiders are very tired. Would be nice to find a reasonably priced drop in replacement.

I just picked up a Model 15 turntable/amp unit, unfortunately sans speakers. My research shows a ported dual 4” driver design for the speakers, but no luck finding the info of system impedance. Would like to harness the maximum power output of this thing by using the proper impedance speakers, so that is the question. Thanks!

Hey guys, bringing this up again. I have a few AR restorations in queue that will be needing grill cloth. Has anyone had any luck with the 18 count or even the 20 count fabric lately?

Hello, has anyone had any luck finding suitable grille fabric? I just checked 123 stitch again, still sold out…or maybe not carrying the 18 ct lambswool anymore.

Sounding amazing and rocking the party, this restored pair of AR6’s, donated from a fellow CSP member. These modern class D Bluetooth amps can take the place of components and sound great, at 40wpc. Residing in a friend of my’s basement bar, just want is needed.

All right Harry, I’ll state what my current status would be. Right now, the AR3’s are back to location, after some minor tweaking of the 9’s UMR resistor (when in LSI mode.) that UMR was just too hot I’m my room, so I added a total of 4 ohms to attenuate it, which did balance it to my liking, but the tweeter seemed to overwhelm, so when I get back to it, I want to attenuate that now. Taking a step back, I thought why not just add a set of 10 ohm pots to the UMR and tweeter? easily allowing room tuning. But again, I strongly think, it’s just MY room and listening position not lending themselves to these huge speakers. All that considered, I will most likely go back to the 2.5 ohm UMR resistor, activated by the LSI switch to keep all crossover points and output the same as intended, since I don’t really want to mess with the design. I do miss the thunderous bass of the 9, but the 3’s still put it out strong. I’ve taken measures to isolate my turntable and with the 3’s in use, I have no feedback issues. Not only do the 9’s make my whole room shake, they do not permit me to listen to the turntable at volumes I am able to with the 3’s. Again, all issues with my listening space lol. The 9’s will probably “stay on ice” for a bit until I find somewhere to set them up to really hear what they can do.

From a few more days of listening, I can say they are voiced very differently than what I’m used to hearing out of my AR3’s and LST’s. Even bypassing the preamp and having my DAC directly into the power amp as ar_pro Suggested, their voicing is still apparent. I’m not saying this is a bad thing, it’s just different than what I have been used to for a long time. Sometimes change is good, sometimes it’s good for a short period. We will see. For the dented mid domes. When the assembly was removed from the speaker, the sides of it were sealed with aluminum tape. I just poked a hole in the aluminum tape and blew compressed air in that hole in a very controlled manor and popped the domes out like that. I also used a hairdryer to get the domes nice and pliable to try to get the ripples out as much as I could, but some still remain. My only comment on capacitors is, the big white film caps are high quality industrial caps by Electronic Concepts out of Eatontown New Jersey, which I always have certain values on hand, but for the values I did not have, are used the Dayton polys. Many vintage AR’s came with Chicago Industrial caps, which fit the form and function and allow the speakers to perform as intended. I have no doubt that these ECI’s and Dayton’s won’t fall short of that.

Roy, I’m using a calibrated Fluke 87v meter. Why I suspect degradation would be from prior experiences recapping older electronics. I’ve noticed the older caps tend to show higher values on this meter as they age. More importantly, on this meter, the new caps, both NPE and film varieties tend to measure very close to their specified values. Granted, Fluke isn’t specifying their test frequency, but I have made comparative measurements with another bench top meter at work, with selectable 1,10, and 100KHz frequencies and this fluke tends to match up with the 10K measurements. Note that I have not commented on any differences of the NPE/Film cap switch. I will not go down that rabbit hole any time soon LOL.

Mission accomplished. Each speaker has an LS/LSi switch, as well as an NPE/poly film cap switch. I’m still waiting on the foam for the bass chambers to arrive as well as one last quad of NPE’s. The speakers are up and running though. The original NPE’s mostly tested higher but still within their tolerance, but to me that is an early sign of degradation. Also there was a mix of three different brands, and also different brands in each speaker in similar locations. i’m pretty sure the speakers are too big for my room, but I must say the bass is extremely impressive, so clean and precise. I have been preferring the LSi position. However I am missing the more polite but still forward midrange presentation of the AR3’s previously in their location. (Edit- I am pretty confident the mid range presentation is a product of my preamp, and it’s suits the 3’s well, I would like to try a different preamp with these speakers) I’m going to get acquainted with these for a little while, but probably going to switch back to the 3’s, mainly due to their smaller stature, being less intrusive to the room. Here are some pictures

OK, revisiting with some clearer thoughts. I have 4 pole switches coming to use as an LS/LSi selector. Poles used as follows: one pole to switch in or out the 1.5 ohm LMR resistor, one pole to switch in or out the 2.5 ohm UMR resistor, and the the last two poles to reverse the tweeter polarity as well as bypass the 5uF cap when LSi is selected.

I had a similar issue with a pair of AR91's. On those, the switches needed to be cleaned with contact cleaner spray and then I was able to hear differences when switched.

Resurrecting this thread, since I am working 9LS speakers. I have some questions for the crossover experts. On the woofer and LMR shunt caps, there is a 0.5 ohm resistor. That small value in the scheme of things seems almost negligible, so what is its purpose? The next question, is not only are 1.5 ohm and 2.5 ohm resistors added in to attenuate the LMR and UMR, but the polarity of the tweeter is reversed, as well as the 5uF cap right before the tweeter + terminal (ls crossover) is eliminated. Why reverse the polarity on the improved, and why get rid of that cap? Im interested in finding out these answers, because I am planning on implementing a LS/LSI switch, to accomplish adding or the 1.5ohm and 2.5 ohm resistors, and also shorting the 5uF tweeter cap when LSi is selected, and of course the opposite when LS is selected. Easily implemented with a 3 pole single throw switch. However, reversing the tweeter polarity wouldn't be possible without another two poles or an additional switch, which id like to avoid. Do you folks think reversing the tweeter polarity would be necessary when using the LSi circuit?

Stimpy, That is a really interesting observation about the new NPE's not sounding as good as the originals. So I was going to add a non-invasive switch to enable or disable the LSi mod, but now I'll add another switch, to switch between the series NPE's or series poly's. Both switches will be added to the connection cutout, over the input binding posts. I'll measure the values of the original caps when this work happens, and if they are still within tolerance, i'll leave the Unicons in place, and just have the pollys as switched option B. Harry, Currently in the room is a pair of AR3's and I absolutely love the forward midrange on those..as dialed in with the pots. These 9ls's will be swapped with the 3's when they are done and hopefully the room won't be too restrictive to their potential. Its essentially an 11'x14' room, with the speakers to be along the 14' wall. In my opinion, the LST's were oversized in that room but still sounded great, only swapped out for the 3's for a more modest look. The soundstage performance of the LST's vs. the 9ls would be very room dependent/restrictive in my situation, but soon to find out.

Well gentlemen, this is my first Teledyne era AR full venture, other than repairs on later drivers etc. Being tipped off down at least a three link chain of CSP folks, I didn’t want to miss out on this opportunity. When they arrived home, my first impressions, is that the woodwork is stunning. Very minor raised spots on the tops, which should be able to be ironed out flat, as well as those water rings should wipe right off with a good cleaner. it’s evident the veneer has been protected with a satin poly from the factory. I’m not too familiar with different wood types, so I wouldn’t really know what type of veneer this is, but I can say the care taken to matchbook the speaker panels is nothing less than impressive. Electronically, well I could’ve done better but at the moment, I am at where the best case scenario would’ve taken me, i.e. just foam replacements. When initially tested, I noted that both 8 inch LMR drivers were dead, as well as both tweeters, along with one UMR sounding surprisingly like a tweeter. First things first, I removed the dome assemblies and noted both were wired very differently to each other, and they were also factory service replacements. referencing the schematic I noted that one of them had the tweeter and the mid domes wires crossed with each other, that would explain the one mid sounding funny. Disassembling the units, I noted that both tweeter leads were separated from the terminals, and only one had continuity at the leads. In my parts stash, I had a pair of spare tweeter diaphragms from a salvaged set of AR58 mid/tweeter plates. I pulled the old diaphragms out and noted lots of crusty ferrofluid, So naturally I cleaned it all out, added new ferrofluid as well as the transplant diaphragms. While I was in there, I was able to blow some compressed air through the sides of the assembly to pop out the mid domes. Next course of action was to figure out why the 8” LMR’s were both dead. Open circuit at the terminals, so A full disassembly was necessary. What a mess, the cone was separating from the voice coil, and I suppose that fatigue stressed the coil leads from the voice coil to the cone causing them to open. Luckily this was repairable, so that is what I did. In the interim, before I investigated this I was browsing the bay, and on a whim purchased a pair of these drivers just in case the repair effort would be unsuccessful, so now I have spares. So now, just dealing with refoams. Having the 8 inchers completely disassembled simplified a rear of the cone attached foam effort. The 10 inchers were a different story. The spiders had some sagging due to the inverted mounting position and probably no foam for a long time. The simple solution was to adhere the new foam to the front of the cone, this very minor modification now allows the normal position of the coil to be in its intended location. Lastly, awaiting a set of foams for the 12’s. Next is to source new foam for the bass box. Also on order, or a full set of NPE’s, and for experimentation, poly films for the mids/ tweeter circuits as well as resistors for the LSi mod. At first everything will be factory configuration with NPE’s, as originally loaded. and then I could toy with the pollys and resistors. and now, some photos!

Hello all, My personal experience with these mids has only been with the potted versions, and they all had a fiberglass disc under the grill, over the dome. I just purchased a large magnet AR3 mid, and this one did not have this fiberglass disk under the grill. The only issue with this, is the grill had fallen off at some point, and was taped on, so that means there’s a chance if there was fiberglass there, it could have been lost. The question is, are these larger magnet style mids supposed to have the fiberglass disc under the grill, or were they produced without it?