ra.ra
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Posts posted by ra.ra
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The tweeter should be part no. 200024, which was used in at least three two-way models: AR-15 and AR-16 with 8-inch woofer; and AR-14 with 10-inch woofer. In every case where this tweeter is used, the crossover is a more complex circuit than is typically found in a two-way speaker model. Since you already have the woofer pulled, can you provide pics of crossover innards?
JKent correctly identified the 027 driver - - it was used as the lower midrange in the AR-9- and AR-9, and possibly elsewhere. DCR for this driver should measure between 4.5 and 5.5 ohms, and it seems to share several characteristics with the 8-inch 037 woofer, so I would think these might be truly fine 8-inch speakers. Can you also offer the cabinet dimensions?
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This thread contains a great pic of a re-capped AR-15 crossover and also discusses some 8-inch AR woofers, but I don't see the 027 woofer mentioned. Looks like your cabinets have been completely skinned with a layer of 1/4" hardwood.
And welcome to the forum.
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Those are really beautiful speakers. It looks to me like someone installed AR-15 drivers (w/mirror-imaging) into a pair of non-AR cabinets, and the cabinets appear to be nearly the dimensions of an AR-4x and with a dark-stained oak? Also, grossly oversized dust caps installed during re-foam of woofer, but they don't look bad at all.
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Yep, genek is correct, these speakers are fully original. In later years, AR-2ax will typically have rear-wired tweeter and square magnet, four-screw, foam surround on woofer. The dark grille cloth is also original, and I have seen it also on AR-4x and AR-5 from Holland, but I don't know if it was ever an option on speakers in the U.S. Your woofers are dated from 1977.
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No amplifier expert here... but the minimal exterior presentation, robust terminal connections, and interior construction and layout remind me of several Adcom amps I've seen. Good-looking power amp! ....
....and despite ebay history, you got a real steal there.
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It seems I may have confused this issue by introducing mention of the third mid-driver - - - to reiterate, it is the 028 mid that is different from the other two, and it is only found in the larger four-way speaker models. The two mid-drivers used in the three-way models - - the 032 and the 044 - - are fully interchangeable and identical with the exception of the color(s) of the plastic face plate (semi-horn).
The dome mids found in the AR-10π and AR-11are indeed different drivers from the 032 used in the AR-91 and 92. I am not able to describe the differences, but I think this topic has been discussed in other threads in this forum.
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6 hours ago, DavidR said:
Not our $$$; not our gear, not our ears, not our concern.
David, your terse response to my comments and to suggest I was "aiming" at Larry makes me think you've missed my points, so perhaps I could have worded my earlier post better. There was no intended snark or criticism - - - in fact, I have great respect for what Larry has done here and his posts routinely remain among my very favorites to read in this forum.
Aside from praising his new crossover work, I was trying to bring up two issues that I felt might address some of the OP's initial questions and parameters. Issue One: I remain very curious to learn about Larry's personal audio evaluations resulting from the terrific circuits he has built for his AR-58s resto-mod project. Adapted boards, new switches, high quality caps and resistors, perhaps soon a subjective A-B test....... This appears to me to be one of the very core issues discussed in this forum, and therefore I think it is "our concern".
Because the OP very clearly stated an explicit budget for this project, the issue of cost is also very much a germane topic for this thread. My curiosity was purposely stated to not be so crass as to ask "How much did this cost?", but I feel that a statement to the OP such as "this solution can be purchased within your budget" could be very helpful, not only to him but to all readers. Three or four other prescriptions with excellent solutions for re-built crossovers have already been presented with great detail - - including rough costs - - and I was merely pointing out that this information was lacking in the one post and therefore left a more comprehensive comparison of the various suggestions unavailable to us.
On 11/1/2019 at 10:33 PM, Darren James said:Question, would you replace the caps on principal?
You've received a lot of great advice and experience in these responses, but this question remains the crux of the biscuit. Mostly from Stimpy, he has best tried to address your question with his own personal philosophy and tastes, and I think he offers some solid advice here when it comes to making value decisions about how to prioritize some component purchases. Darren, please follow up and show us how your project is progressing.
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1 hour ago, ar_pro said:
That's really nice work, Larry - I especially like your positioning & management of the new resistors and stacked caps.
I totally agree - - the physical layout of these resto-upgrade crossover projects on existing boards can sometimes be the biggest challenge and these look terrific, and using high quality components. Really great write-up, Larry, and very impressive circuit assembly, too.
1 hour ago, ar_pro said:Please let us know how you wind up setting the new level controls on the AR-58S, and if you decide to keep the Tonegen woofers, or the original drivers. I think the Tonegens might not get the respect that they deserve - they are excellent woofers.
More very good comments, ar_pro. A subjective evaluation of the level switches installed in the AR-58s is what I am curious about, too. And also, I think I agree about the Tonegen woofers - - despite my general preference for the originals, I've been unable to detect noticeable differences in AR speakers where I've encountered Tonegen drivers.
1 hour ago, Stimpy said:.....you should A/B them. You'll be shocked how much better the new board will sound.
Good point.... I agree - - with this amount of crossover replacement, an A/B comparison is essential. But still, I'd really like to hear Larry's own performance evaluation assessment of this transformation. With 22 new components installed on each crossover board, the cost of this installation enters the discussion relative to earlier posts, and the bang-for-buck debate deserves consideration in this evaluation.
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13 minutes ago, Giorgio AR said:
One of my doubts is also to invert the small identifying labels so as to make it indistinguishable from the original, but in this way I would make a fake!
What you've done with paint on the frontside seems perfectly fine for your intended purposes, but it was also a good decision to not make the change on the rear label. By doing so, you could have easily lost track of not only that driver's origin, but also its date of manufacture.
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1 hour ago, Darren James said:
They are ... black with red ends....
Yup, those caps gotta go ..... pic attached is from 1972 Smaller Advents with two caps paralleled to make 16uF - - - when I removed the tape to confirm the value, it could be seen that the 12uF cap had cracked and split lengthwise.
13 hours ago, Darren James said:I found a pair of correct woofers......What an ugly crossover!
You're getting some good advice on re-cap process. If you could, plz post a couple pics of new woofers and crossover.
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On 10/26/2019 at 11:04 AM, yoram611 said:
I just bought a pair of AR-3a ... hope someone can help me understand what was done and if I should leave it as is or make any changes ?
Hi Yoram, welcome to CSP. There are so many wires shown in your pics that it's difficult to see what is going on. You do not need to be an electronics wizard to work on these speakers, but you will need to backtrack a bit to begin to understand exactly what needs attention in order to get these speakers re-assembled properly. While you have not yet commented on their current performance, it does seem that with the exception of excess wiring, all of the other bits (caps, coils and pots) appear to be original components.
First things first: before you do anything further, you should take the time to read the invaluable AR-3a restoration manual that is found on this site. Some portions will not be applicable to your particular pair of speakers, but nonetheless you should review the entire document. Much of what you need to know can be found on page 10, which shows a crossover pic with the exact same caps as yours, but more importantly, a full wiring schematic for the entire speaker circuitry. Start there, and then feel free to ask for help - - this site is full of people with much experience restoring 3a's.
My suspicion is that, to some extent, eventually you will need to take these apart and re-build them. I would not advise eliminating (or "bypassing") the rotary controls (but they might require replacement) and it's even quite possible that your capacitors will not require replacement - - who knows yet?
So.... read up....dig in....and ask questions. And be sure to take pics along the way for your own documentation.
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Hi Giorgio, your work looks very good and is a simple and clever adaptation for cosmetic purposes. One small correction - - you seem to have the drivers mixed up - - the 032 midrange was used in the AR-92 while the 044 midrange was used in the AR-58s. More importantly, however, is that you have correctly noted that functionally, these two drivers are fully interchangeable among these 3-way speaker models.
The plastic face plate that you have painted is termed the "semi-horn" on all of AR's fabrication drawings. There is a third AR mid-driver from this family that is very closely related and nearly identical - - part no. 200028. The 028 mid is found in the AR-9 and AR-90 - - both 4-way speaker models - - and the only physical difference is the amount of ferrofluid which affects its lower limit crossover point.
A brief summary of these three mid-drivers:
- mid p/n 200044 - - model AR-58s - - above 700Hz - - horn p/n 204096 - - color: all black
- mid p/n 200032 - - model AR-91 and 92 - - above 700Hz - - horn p/n 204085 - - color: brown w/silver paint
- mid p/n 200028 - - model AR-9 and 90 - - above 1200Hz - - horn p/n 204079 - - color: black w/silver paint
For future reference, I'm pretty certain that the plastic semi-horn can be fairly easily removed from the robust metal parts of these drivers. I seem to recall seeing on these pages a very clever project where RoyC adapted one of these drivers for use in an AR-3a or AR-5 cabinet. In that instance, I believe he removed and abandoned the original plastic horn and - - for cosmetic purposes - - replaced it with a domed screen grille cage that is typically found on the mid drivers for the AR-3a and AR-5 speaker models.
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9 hours ago, prairieboy said:
A personal thank you to stickman from me....
Ditto from me.
That sounds just like the sort of information that stickman was generous enough to share with me, and I appreciate you both sharing it again here in such detail.
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Thx for response. Many of us understand this issue of having an abundance of speakers, and you are correct to note that the LST speakers really do deserve an environment and placement that takes advantage of their unique capabilities. Best of luck finding a proper home for them.
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Great-looking speakers, Giorgio.
Still, curious minds want to know: why are you selling? You'll almost never find another pair in such condition.
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Too much catnip?
Sorry to see that misfortune, Peter. I've had good success repairing small tears in paper cones, but that cone of yours appears beyond fixable. I suppose re-coning is always an option, but the cloth surround and mesh dust cap present unique conditions that will make that process a real challenge. Maybe Millersound is capable of the repair, but I suspect procuring a suitable replacement woofer would be less costly. BTW, is that woofer from the pair of 4x's you picked up at the spring fest?
16 hours ago, lARrybody said:I don't know what the differences may be...
Yeah, me neither....this is a good question. Despite the variations in appearance, I've always thought that the various 4x woofers had similar performance attributes. I know I've seen at least three types-colors-textures of 4x cones, and maybe some minor differences in basket profile or construction. At some point, the 4x switched from using a #4 to a #5 coil, but I don't know if this reflected a change in the magnet structure or some other concurrent adjustment to the woofer specs.
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Hey, I'm real pleased to hear that you made the effort to contact stickman, and I was pretty certain he could be helpful. If you have any additional information on these speakers that you wish to share, this is a great place to post it for posterity or further discussion.
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Oops....I have corrected a small but important mistake in my earlier post.
Re: patching solution, Glenn is an excellent restorer and a generous source of much information regarding various speaker models, but his suggestion was intended only for original cloth surrounds. Once a foam surround has degraded to this level, there is no "fix" that can restore its functionality short of a complete replacement.
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#1 - Don't worry about this - - if it needs to be moved, the site moderators will take care of it.
#2 - I don't know these Mission speakers at all, but none of my very limited reading suggested these were foam surrounds. With age, foam surrounds become dry and frail, and often crumble at just the slightest touch. A helpful tool to confirm surround material is a magnifier - - if cloth, you should be able to clearly see the weave of the fibers in the fabric, as in pic attached, which shows a small tear in the rolled portion of a 50-year old woofer.
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On 10/25/2019 at 2:30 PM, Eabos1 said:
The values were: 8uF, 5uF and 3 ohm...
Hi Eabos, and welcome to the Advent forum. I know I've never seen a 5uF cap used in a Smaller Advent crossover, but I think they were at least three known variations for this circuitry. Can you post a pic of the original crossover (or the removed caps)? And also, do your tweeters have red or green fronts, and what is dimension of tweeter magnet? Did your Solen re-cap result in any perceptible improvements?
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11 hours ago, brownrock said:
I am considering replacing the existing surrounds which are fabric (silk???) with foam surrounds...
Hi brownrock, and welcome to the CSP forum. (Just FYI in the future, threads such as this one should be posted in the "Other Speakers...." section rather than the Acoustic Research section.)
Your photo is pretty good, but are you certain this is a fabric surround? To me that certainly looks like a foam surround - - not cloth - - and it appears to have deteriorated on those circumference edges which is a very typical location for aged and brittle foams. And even if they are cloth, this would be an extremely challenging repair given the size of the driver and the complex configuration of the location of those splits.
New fabric surrounds are available, but they are not very common. My advice would be for new foams, as discussed in this thread.
https://audiokarma.org/forums/index.php?threads/interesting-speakers-incoming-mission-720.817658/
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2 hours ago, teknofossil said:
....the previous owner did a nice job modifying these......Modifications to the cabinet appear minor.....
I think I might tend to disagree with these two statements, but here are the schematics I've found. The Heathkit AS-2 was a kit version of the AR-2 that used authentic AR drivers. Also attached are pics of original AR-2 crossover components.
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On 8/13/2019 at 6:22 PM, Justin said:
I have a set of d-8 speakers myself. I am going to start restoring them soon....
10 hours ago, prairieboy said:Hard to find a lot of details on them...
Welcome to the forum, prairieboy, and am pleased to hear your favorable impressions of these speakers. The D-8's are pretty rare, and it is difficult to find much info on this model. My suggestion to both of you is to contact a member on the Audiokarma forum who goes by the name "stickman" - - he used to work in the original factory in Torrance, CA in the 70's and is the go-to source for information on the original DA lineup of speaker models. I have had some extensive correspondence with him regarding some DA D-4's, and he has always been very helpful and gracious.
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5 hours ago, MikeD2 said:
....and will likely use it on the 3a cones...
The dope is generally not intended for the cone surface - - it is meant for coating the fabric surrounds (and some KLH dust caps). Please see your recent 4x thread for further suggestions.
....and despite ebay history, you got a real steal there.
What model number are these speakers?
in Acoustic Research
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Are those AR-7 badges?
Yep, nearly identical to AR-4x cabinet.
Nice quality components and fine workmanship. It appears very different from the AR-15 crossover, but it looks like someone knew what they were doing.
And have you auditioned the AR-7's yet?