A pair of AR-MST Improved

[VintageMan]

I'm looking at a nice pair AR-MST Improved.

I cannot find much here on this forum other then the topic Kent pointed me to.

I'm curious what a decent price would be to offer, or what their value is?

Is it worth buying or should I wait for other models like the AR-LST?

Are they similar to the AR6?

They look really nice, and although I'm not in need of yet another set, they are: tempting

[owlsplace]

I think there are not many MST's out there. I would grab a pair if I saw them. Another attempt to solve the limited power handling capability of AR's tweeters? I solved that problem with three pairs of 6's. I imagine the mirror-imaged MST's would be great in a small room with proper placement. Prices are probably all over the place these days.

Here's a quote for you from http://www.vinylengine.com/turntable_forum/viewtopic.php?t=47644:

The MST was a poor-man's LST-2 and a destitute man's LST. Excellent for a small room, typically and disproportionately power-hungry (as with any AR of that vintage) and capable of an excellent, wide soundstage within the limited bass response.
The 6 is more-or-less a 4x after going through body-building. The MST is more-or-less a 4x on body-building with steroids if you want a point-to-point comparison. I would prefer the MST over the 6 at any time and day.
Peter Wieck
Melrose Park, PA
(AR3a/AR4x/AR14/ARM5/AR Athena/Maggie MGIII/Revox Piccolo)

SteveF liked them: http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=7385

Roger

[VintageMan]

Roger, thank your for all that info.

Interesting read!

I now have to think about the asking-price and if I can get away with it at home

[ra.ra]

The MST is a bit of a rare bird, but not one of AR's most whole-hearted efforts. I believe it may have been the final model to sport the popular walnut and linen look, but it was released concurrent with the onset of the ADD series, which had a very different appearance. I am pretty certain that the "Improved" version was also sometimes known as the "MST-1", each of which had the three tweeters, as opposed to the original "MST" which had four tweeters (and subsequent performance problems).

I happen to own a single MST that I enjoy tinkering with, after locating an empty cabinet sometime last year, but having a properly functioning pair could be a lot of fun. The 8" woofer and 1-1/4" tweeters are very much the same as the drivers from the AR-6, AR-7 and AR-4xa.

About prices - - - something like MST's does not come up for sale often enough to establish much of a data base - - so it really comes down to each unique transaction between seller and buyer. This 3-tweet pair in Bologna was seeking 450 Euros, while a 4-tweet pair in the U.S. is currently asking $300, while a recent thread in this forum noted a pair for sale in the US for $125.

[VintageMan]

Thanks ra.ra for the info.

The seller asks € 350,- , compared to the € 250,- I paid for the AR3a's and the same for the AR3a Improved I find it a lot.

I think they are a welcome add on, but I'll wait for another set.

[owlsplace]

...

I happen to own a single MST that I enjoy tinkering with, after locating an empty cabinet sometime last year, but having a properly functioning pair could be a lot of fun. The 8" woofer and 1-1/4" tweeters are very much the same as the drivers from the AR-6, AR-7 and AR-4xa.

...

The AR-4xa uses the vented woofer the same as the 4x which is quite a bit different from the woofer in the 6 and 7 models.

I haven't seen a crossover diagram for the MST/1 model and am curious what changes were made there.

[ra.ra]

Roger is correct that many early 4xa's used the cloth surround woofer from the 4x production run, but I was referring to the later 4xa models with the foam surround woofer, as shown it the two pics here. Timewise, these woofers more closely paralleled the production of the AR-7 and the MST. Also, I've included a brief statement where Roy summarized about the 8" universal woofer from another 4xa thread in these pages.

Re: MST schematics, I'm fairly certain both versions are included in one of the threads about this model. If unable to locate, I could furnish them again.

to VM: yes, the MST's would be a fun addition for a collector like yourself, but I agree, they should not be fetching higher prices than any model from the "3" series.

[owlsplace]

Interesting, RoyC's comment verifies what I would expect -- the voicing changed with the switch to the sealed foam universal woofer.

Collector value usually boils down to demand and availability. There are plenty of 3's out there and few MST's. Lack of demand keeps the MST's price down.

Yes, found the AR-MST and MST/1 schematics for reference:

Roger

[ra.ra]

Thx, Roger - - - yep, those look like the two schematics that I have seen. On the original four-tweeter version, what's interesting to me is that I don't see any depiction of the tweeter control switch, and presumably, its two associated resistors. IMHO, the MST-1 is more interesting, not only because it attempts to correct the interference performance problems associated with the original design, but because the tweeters now have two different crossover points - - sort of like creating one super-tweeter - - and it also establishes the first truly left-right mirrored pair of "classic" AR's since the AR-1 and AR-2.

The history and evolution of AR's 8" woofers is a long and interesting (and confusing) story, but after your comment about the "vented" 4x woofer and its mesh dust cap, I remembered that a similar situation exists on the 8" woofer (p/n 200050) that was used in the AR-28B (see pic).

About your market pricing comments, I think you are mostly correct, but regarding the MST, it can also be stated, in economic theory, that its limited supply should be responsible for keeping its price up. I won't debate the desirability comparison between the MST and any of the 3's, but the fact is that very many followers of vintage audio are familiar with the legendary AR-3 speakers while at the same time, very few have ever heard of the final hurrah in this original AR series.....the AR-MST.

The only AR literature I've ever seen about the AR-MST is attached, courtesy of one of our Euro experts - - either Robert_S or Klaus - - and of interest, it notes that the MST has significantly increased power handling capacity.

[tysontom]

Thx, Roger - - - yep, those look like the two schematics that I have seen. On the original four-tweeter version, what's interesting to me is that I don't see any depiction of the tweeter control switch, and presumably, its two associated resistors. IMHO, the MST-1 is more interesting, not only because it attempts to correct the interference performance problems associated with the original design, but because the tweeters now have two different crossover points - - sort of like creating one super-tweeter - - and it also establishes the first truly left-right mirrored pair of "classic" AR's since the AR-1 and AR-2.

The history and evolution of AR's 8" woofers is a long and interesting (and confusing) story, but after your comment about the "vented" 4x woofer and its mesh dust cap, I remembered that a similar situation exists on the 8" woofer (p/n 200050) that was used in the AR-28B (see pic).

About your market pricing comments, I think you are mostly correct, but regarding the MST, it can also be stated, in economic theory, that its limited supply should be responsible for keeping its price up. I won't debate the desirability comparison between the MST and any of the 3's, but the fact is that very many followers of vintage audio are familiar with the legendary AR-3 speakers while at the same time, very few have ever heard of the final hurrah in this original AR series.....the AR-MST.

The only AR literature I've ever seen about the AR-MST is attached, courtesy of one of our Euro experts - - either Robert_S or Klaus - - and of interest, it notes that the MST has significantly increased power handling capacity.

Additional information on the original AR-MST-1 is attached. AR printed color literature on this speaker as well as the black/white version.

--Tom Tyson

AR-MST-1 Color Literature_17March1975.pdf

[owlsplace]

TomT,

That clarifies the situation a bit. There must have been a bit of a void at AR after Roy Allison left judging by the first version of this model. If the second version had come out a year earlier I may have picked them over the AR-5.

If you were going to try to build one of these from scratch today you could expect to spend around $600-$800, maybe more, so that may be an indication of their value -- at least to someone wanting a pair.

Roger

[ar_pro]

Great color brochure, Tom.

Look what else is revealed in the photo - the AR amplifier with a headphone jack, and an XA turntable with some sort of arm lift mechanism.

[ra.ra]

Yes, thanks very much Tom, for providing both this brochure and the corresponding schematic in a prior thread - - I doubt many members have ever seen this literature before.

Very astute observations by ar-pro. We have discussed that rare headphone jack before, but what's up with that cueing device lurking behind the beer stein? Not particularly germane to the topic at hand, but I also note a couple of Hasselblad cameras, a Miles Davis album, and the proverbial bottle of wine (alas, empty ), suggesting the ethos of the sophisticated urban cool lifestyle. More to the point, I notice that the speakers on each page are sporting different grille badges.

The pic on page 2 is interesting to me for two other reasons. First, it cleverly places the cab w/grille in front of the unclothed cabinet in a way which largely shields the blank (driverless) angled face. More importantly, it shows that the preferred layout of the tweeters is for them all to be positioned along the same line of latitude, as opposed to some which were released still using the original MST cabinet and included the blank-off plate for the unused cut-out of the earlier four-tweet product (see pic).

In several regards, the text is well-written and somewhat revealing as well. Along with the descriptions of the various components and the speakers' variable room arrangements and settings noted on the first page, a number of specific revisions to the 1-1/4" tweeter are highlighted in some detail. Also, while not quite stating overtly, there is a not-so-benign reference made to the interference problems associated with the earlier four-tweeter design.

The second page nearly refers to the front-facing tweeters as mid drivers, which is essentially correct, and also features an interesting outline for beginning to understand some thinking behind recommended power requirements. And this is the first time I've seen the cabinet volume described accurately (which is the same as AR-4's and AR-6's), despite the cabinet depth noted here as 1-1/2" deeper than the Euro literature (attached).

[tysontom]

TomT,

That clarifies the situation a bit. There must have been a bit of a void at AR after Roy Allison left judging by the first version of this model. If the second version had come out a year earlier I may have picked them over the AR-5.

If you were going to try to build one of these from scratch today you could expect to spend around $600-$800, maybe more, so that may be an indication of their value -- at least to someone wanting a pair.

Roger

Roger,

Roy Allison left AR in 1972 after the Teledyne, Inc. "Five Year" employment agreement had expired. Edgar Villchur had arranged—as a part of the original 1967 purchase-agreement with Teledyne's CEO and founder, Henry Singleton—to give all senior executives a 5-year employment contract at AR. This included Roy, Abe Hoffman, Jerry Landau and perhaps a few other executives. After 1972, however, Roy left AR to work on his new Allison designs, and he therefore had nothing to do with the final implementation of the AR-MST; in fact, the MST was the work of several resident engineers at AR at the time, one's involved with the new Advanced Development Division speakers AR-10Pi and AR-11. Quite a bit of development was done in AR's United Kingdom facility as well. After the move to Norwood in 1973, AR did expand its engineering staff significantly.

—Tom Tyson

[ar_pro]

ra.ra,

I've seen Tom's brochure before, but it's been years & years.

The freshness of AR's advertising ethos left a mark; I'd mentally stored the look of that MST color ad, and about 25 years ago, my wife & I built the shelf system for our home office shown in the attached photo.

It's funny how some things stay with you!

[owlsplace]

Roger,

Roy Allison left AR in 1972 after the Teledyne, Inc. "Five Year" employment agreement had expired. Edgar Villchur had arranged—as a part of the original 1967 purchase-agreement with Teledyne's CEO and founder, Henry Singleton—to give all senior executives a 5-year employment contract at AR. This included Roy, Abe Hoffman, Jerry Landau and perhaps a few other executives. After 1972, however, Roy left AR to work on his new Allison designs, and he therefore had nothing to do with the final implementation of the AR-MST; in fact, the MST was the work of several resident engineers at AR at the time, one's involved with the new Advanced Development Division speakers AR-10Pi and AR-11. Quite a bit of development was done in AR's United Kingdom facility as well. After the move to Norwood in 1973, AR did expand its engineering staff significantly.

—Tom Tyson

I crafted a reply but it looks like it disappeared into the ether. Basically it reflected on RoyA's one-year "non-compete" clause and the timeframe of Allison Acoustics offerings of which I have never seen any in person. I did look at the 1978 Allison brochure in the archives.

Seems like AR screwed-up on the original MST offering for some reason, not that it would have been any competition with RoyA's towers. Not sure when Allison Acoustics actually fielded any speakers. Then came the "butt-ugly" AR-9's which apparently sounded great but I think I would have been looking hard at the Allison Ones if I had been a player at the time -- all conjecture, of course.

I wonder how the Allison drivers held up over time compared to the classic period AR drivers?

Roger

[iso]

Great color brochure, Tom.

Look what else is revealed in the photo - the AR amplifier with a headphone jack, and an XA turntable with some sort of arm lift mechanism.

Colton Varilift was used on many AR-XA`s here. As Colton lift was of UK origin, it may have been used mainly for european models.I do not remember if the lift was used as OEM or bolt on accesssory. Lift on the pic looks like Colton anyway.

Best Regards

Kimmo

[tysontom]

I crafted a reply but it looks like it disappeared into the ether. Basically it reflected on RoyA's one-year "non-compete" clause and the timeframe of Allison Acoustics offerings of which I have never seen any in person. I did look at the 1978 Allison brochure in the archives.

Seems like AR screwed-up on the original MST offering for some reason, not that it would have been any competition with RoyA's towers. Not sure when Allison Acoustics actually fielded any speakers. Then came the "butt-ugly" AR-9's which apparently sounded great but I think I would have been looking hard at the Allison Ones if I had been a player at the time -- all conjecture, of course.

I wonder how the Allison drivers held up over time compared to the classic period AR drivers?

Roger

I made a mistake about Roy Allison's tenure at AR: he actually left AR in 1973, not 1972.

The AR 5-year contract agreement ran from June 1967 through 1972, but Roy left AR soon after that in 1973, and he began to work on his Allison designs, based on the wall-dip phenomenon (long-established, but poorly described in earlier literature) to become known as the "Allison Effect." Roy completed his woofer designs, such as the first model Allison: One, Two and Three, which had acoustic-suspension woofers very close to the floor-wall intersection, thus alleviating the dip in bass response caused by reflected-wave cancellation, but he also developed his wide-dispersion mid-range and tweeter designs, pulling them all together in the new Allison models. This took over a year to complete after leaving AR, and Allison Acoustics was formed in 1974.

BTW, what 1-year non-compete clause are you referring to regarding Roy Allison?

The AR-MST/1 in no way was intended to compete with any of the Allison models, so there was no screw-up with regard to marketing the MST against the Allison brand. There might possibly have been vague competition against the Allison: Four, which was introduced in October 1976, but the MST was introduced a year earlier in 1975, so there is no competitive linkage there. The MST/1 was intended to bring "near" AR-LST levels of sound quality to discerning listeners, but at a much more entry-level price. It was also intended for recording studios and monitoring locations wanting the very wide-dispersion acoustic-power capability of this speaker.

Allison drivers have held up fairly well. The woofers are subject to the same oxidation process as AR woofers with urethane-polymer surrounds; the mids and tweeters suffer from drying-out Ferrofluid and silicone grease in the gap, but otherwise the drivers are fine. Crossovers usually need updating, too. The Allison 10-inch woofers used in the model One were no match for the 12-inch AR woofers used in the AR9, but then again, few other speakers can match the AR9 in any respect.

—Tom Tyson

[DavidDru]

Ahhhh, reading this great history lesson while listening to Allison Ones here in my office. Great stuff guys and thanks for contributing such.

[owlsplace]

I made a mistake about Roy Allison's tenure at AR: he actually left AR in 1973, not 1972. ...

BTW, what 1-year non-compete clause are you referring to regarding Roy Allison?...

—Tom Tyson

I read that somewhere. I'll keep a lookout for the reference.

Ahhhh, reading this great history lesson while listening to Allison Ones here in my office. Great stuff guys and thanks for contributing such....

Ah, a man with taste

Enjoy

[owlsplace]

.... The history and evolution of AR's 8" woofers is a long and interesting (and confusing) story, but after your comment about the "vented" 4x woofer and its mesh dust cap, I remembered that a similar situation exists on the 8" woofer (p/n 200050) that was used in the AR-28B (see pic). ...

050 woof.jpg MST p.1.jpg

Wasn't aware of the vented cap on the 28B woofer. Looks like it had its surround attached to the back of the cone also. The design looks a bit different from the 4x woofer which used an alnico magnet with vented covers allowing air-flow, or perhaps even pumping air through the voice coil.

Roger

[ra.ra]

Indeed, there are a wide variety of 8" drivers that were used in the many speaker models over the years, and it does get confusing when trying to conclude which drivers might serve as suitable replacements for a particular speaker project. About the 28B woofer (p/n .....050), you are correct about the cone-surround interface, as shown in the re-foamed pic attached, where you can also see the light glue line where I re-installed the mesh dust cap after shimming.

In the parts list for this woofer, the cap is described as "dust cap, appearance". (This same cap p/n and identical description show up in the parts list for 8" LMR p/n 200045 which is employed in AR-9LS and AR-98LS speakers, models unfamiliar to me.) This description is different from the one which says "cosmetic dust cap" and shows up as a second domed cap installed over a primary flat cap. I know the double dust cap shows up on at least two 8" drivers: p/n 200027, which is LMR for AR-9, AR-90 and AR-94; and p/n 200001, which served several smaller models and may have become the "universal" woofer.

The other odd thing about this 050 woofer is the basket shape, which has a second level of pressed metal where it abuts the magnet. This layer is about 9/16" deep, but I've not seen this particular basket profile on other AR woofers.