valkyrie

In response to the query how does a Dynaco ST-70 perform driving an AR three way; I have some hot-rodded ST-70s, set up as monoblocs driving my AR-91 speakers. These amps, using a 2252 Marantz as a preamp, drive those speakers WONDERFULLY. My ST-70s have been completely retubed (JD-8s instead of the impossible to find 7199s and New Sensor EL-34s), recapped - using "orange drops" in the signal path, and have had their chokes on the Pi sections replaced - with of course as I am wont to do, new wiring installed. The sound is to die for - lots of power - sufficient to drive as loud as I want to hear and the tonalities are spot on - the classic "tube" sound with lots of transformer sweetness. AR three ways, of which the 91 is by some people's taste the BEST of all the AR three ways, really sound musical with a tube amp driving them. I would estimate that my ST-70s are putting out about 65 wpc - with a good portion in Class A as I have upped the bias from the nominal 1.56 vdc to about 1.9 vdc - they run HOT. Pushing the mains transformer rather hard. But the sound!!! This is my "garage" system - the main system consists of AR-9s and Pass amps.

I would buy such a book. WoW!!!!!! Push on please.

StereoPILE is a ridiculous semi-literary publication that exists only to serve as the marketing arm of an inane industry gone insane. The "editor", one John Atkinson, assuming such a second rate scurrilous rag actually requires any editing, is a raving anglophile who pushes all things English - no matter how constipated, shelved and dull those offerings actually are. English speaker sound - for the deaf and dumb. Recently I had an opportunity to do a shoot out between some classic Spendor 3 way - dating from the eighties. Versus my set of AR-91s, arguably the BEST of the AR three way offerings. It was NO CONTEST. The English sheet box came across as mechanical, dull, lacking any articulation or clarity, lumpy in the extreme and lacking any real bass - other than the sound of air whooshing out the port. In short? A speaker that would never have been able to compete against ANY AR offering - at least from the period between 1960 and 1985. Always remember that the "high end" (or is it high colonic?) industry exists to sell second rate junk at absurd prices. Part of their mission to accomplish this goal is to instill in soft minded and uncertain readers the feeling that price can somehow be equated to quality of sound. Which is absurd on the surface and ridiculous upon any reasonable investigation. The rags work by intimidating their goofy readers with the self-anointed and self-appointed "golden ears" of their so called "reviewers". In other words, the filthy rag and their high school scribblers will do all thinking FOR YOU. As such the diminution of classic American products from the seventies and eighties is de riguer to achieving their aims - to sell more modern crap at ridiculous prices. I have heard Wilson AudioAlexia, driven by Momentum electronics, sourced by an MSB DAC and positioned by a master setup person, one Peter McGrath. Was it good? Oh my goodness - it made for a magnificent sound. Simply awesome. But the ticket for that rig was $100,000+. Was the sound worth the price of admission? NO - that is an ludicrous amount of money to spend for reproduction kit. Point being that SOME of the modern gear is really quite capable. But the affordable modern offerings, such as Harbeth speakers feature performance that is in no way are commensurate with the price being charged. We need to ask ourselves - who is Herb Reichert and who appointed him to be any kind of arbiter concerning what constitutes truth and beauty in sound reproduction? Can we see Mr. Reichert's hearing tests? Can we hear his room? Do we know anything about this golden eared critic? NO - nothing at all. Other than JA hired him to write the party line at StereoPILE. Bunch of envious lies designed to lead folks away from some of the best available sound in the hear and now. Diminish in any way possible the considerable accomplishments of the American sound reproduction industry - less somebody discover that the current uber expensive gear is actually somewhat ordinary - at best.

I can add a little something to this discussion that might shed some light on why there was dealer push back per AR sales and promotion. Circa 1975 I was living in and about Los Angeles. From time to time, say about once every three months in the "Stereo For Sale Ads" of the L.A. Times I would notice a short ad that promoted "AR speakers at Dealer Cost". Various models would be listed, AR2ax, AR3a, AR4 and the prices would be approximately HALF of what Pacific Stereo - my "go to" store - would list the same items. One Saturday I decided to investigate further. The address listed was in Seal Beach, just south of LA proper so a short drive down PCH led me to a smallish, cinder block building in a parking lot adjacent to the beach. There was a short line of folks waiting to enter this building. Once I gained entry the "store", about 20' square was stacked floor to ceiling with AR speakers - new in the box. You told the "salesman" what you wanted and he pulled it off the stack, you paid IN CASH and you were on your way. When you got home you found that you had a full-up, original AR speaker with all the associated warranty cards. Nothing was amiss with the product. This of course had to be some "back dock" special. I have heard rumors - totally unsubstantiated - that if you had the cash and an 18 wheeler, you could pull up at the AR mother-ship in Boston and load out all the speakers you wanted during this era - at wholesale cost, with no questions asked. I never saw any of the ADD vertical products for sale - but ALL of the classical era speakers, including 10pi, AR-11, et cetera were available. I bought my first AR speaker, a set of AR-2ax at this place - I almost pulled the trigger on some AR-3as but even with the dealer cost break that was still a stretch for my limited finances. Wish I had. I wonder if this was calculated into retail dealer reluctance to push AR product? A savvy retailer had to know this was going on - it was a regular occurrence and everybody who was "into" AR knew about these events. Though by '79 when I bought my AR-10pi speakers the back door deal had not been in the paper for several years. So Pacific Stereo got the business - along with a Marantz 2265B - perhaps the sweetest receiver I have ever heard. Darn good rig that one. Was it perhaps AR moving out models that had been obviated by later designs? Or was it some clever entrepreneurs working an angle? It is said at that time that a lot of illicit product was moving from Southern California to Boston - perhaps this was a way to "round trip" the transportation costs? Whatever it was it went on for years - and left a lot of very happy folks around LA.

No - the 91 is amazing - a real treasure from AR. Now I am prejudiced towards the AR sound - have been all my life. But to my ears, the 91s are much superior to the AR-3/a models. Brighter, greater clarity, a more tilted up sound. Those are some really excellent speakers. As previously pointed out the 91s were never on the radar - never reviewed, never much mentioned by anybody - sort of in the shadow of the Mighty Nine and the 90 models. BTW: The room that was used for measuring is NOT FRIENDLY to wide dispersion speakers like an AR. My friend is one of those audiophile types who listens "near field" and has lined the room with cabinets containing books, records and CDs to suppress/absorb/diffuse off-axis sounds. Just his style of listening - and John Atkinson the editor of StereoPile has the same setup - the long axis of his room is absorptive/diffuse - lined with all kinds of crap. The result being a relatively dead sounding room. Many of the "audiophile" types like that kind of environment - it allows them to enjoy speakers that are not very dispersive. You only hear the main beam in the "sweet spot". Not my way or preference. I think if those 91s were placed in a more reflective room (like my own) and some optimization were done on their positioning that they would be giant killers. They easily held their own against a Magnepan Tympani I-D - which to some is the best speaker that Magnepan ever made. I am amazed at how good the 91s sound.

A few months back there was some discussion concerning which AR three way was the definitive, best sounding unit. As I recall the author had mentioned that he thought the AR-91 was that model, since it was the outcome of the ADD research and used the same midrange and tweeter as the AR-9 family. This discussion piqued my interest as I was looking for a nice AR three way with the 12" woofer to replace my second system AR-2ax. AR3/a are out of the question due to their high prices (> $1000). Rarely does one see an AR-10pi or an AR-11 for sale. Lo and behold - shortly after this topic appeared I found a "nice" set of AR-91 on flea bay. The guy wanted $600 - but this was a cherry set - with the original absorptive pads on the baffle - all of them. Very rare. Cabinets were good - no chipped veneer - some water stains on the top of one speaker - but overall very good. That small still voice told me; "BUY THESE". So I took a flyer and did so. Received them in good shape and put them into play. I was amazed at how good they sounded - just knocked back. The woofer had been new surrounds and I "suspect" that the crossover had been updated - they had that brighter, more forward sound that I associate with a freshened crossover caps (I do not know for sure whether or not this is the case - I have not been into the speakers). So I took them to my audiophile friend's house - and we tested them in his dedicated listening room. Full ARC stack (including the REF-40 preamp and the mono-bloc 210 watt tube amps). A very nice setup. My friend has a FR measurement system so we ran some pink noise plots on these beauties. BTW: there was NO ATTEMPT on our part to optimize the location of the speakers for the room - it was strictly "first seat available" which, in this case meant they were located about 6' apart on a TV stand - with a giant flat screen between them. The rake (or toe in) was arbitrary and the attenuators were set to zero dB. Here is a picture of the setup - looking towards the speakers from the position of the mike - the 91s are on the shelf on each side of the flat screen (I cannot seem to place a photo "in line" so the first attachment is the test setup. The mike is on a boom leaning over the couch with its position about where a head would be. The black panels to the side of the 91s are a set of Tympani I-D (the model without the ribbon tweeter) and the two small speakers on stands are Spendor SP1-2 (English three way from the same approximate era). All of these speakers were compared to the 91s. But first here is the F/R plot - again - no attempt was made to optimize speaker setup - and the speaker cables were BB 14 gauge - no upscale stuff. But the ARC stack was first rate by any standard. The humps and bumps from 120 Hz or so down were no doubt room driven. But really good performance from a very old speaker (I figure about 36 years young). This plot was a done with smoothing - but I cannot remember the value. Overall an excellent performance - both objectively and subjectively imo. Subjectively the 91s crushed the Spendor speakers - rendering the Spendors as rather mechanical and unable to pull out musical textures in complex lines. Against the Maggies the results were equivocal. If you like the Maggie "sound", lots of sound bouncing around all over the place, limited dynamics, and not much in the way of bass - the Maggies were good - but my friend used every tweak and adjustment known to man in setting up the Maggies - while the 91s were just located without any effort at room optimization (and such makes a huge difference in speaker sound). Overall? The 91s are a great bargain - if you like the classic AR sound then that model is indeed a superb speaker.

Great write up - thanks so much for the charts and pictures!!! Excellent engineering work!!! I have the same problem with my AR-9s - that graininess that clearly is coming from the UMR. So I am going to order the recommended parts and see if they work in my situation. Again - many, many thanks to both the author and all those who contributed. Great forum!!!