I had a pair of 1+1 with medallion xformers. I worked at an Acoustat dealer and got them on the dealer discount. Man I loved those speakers. For some reason, that is still beyond me to this day, I sold them to a coworker. He just pushed too much money in my face.
Any way . . . . . I am curious if you had anything to do with the electronics side of Acoustat. In the 80's Acoustat offered a power amplifier.
What was different was the output stage. It was mosfets in a push -pull configuration. The sources are tied together is what looks like a conventional sources (or emitters) tied together to make the +, red, hot, not the ground, output terminal.
Instead, acoustat GROUND the source to source, junction. (aka positive speaker terminal of most other amps) You would think that nothing will come put of the amplifier, after all ground to ground. But they somehow let what would be the ground (aka black, ground, negative) speaker terminal, that swings up and down the rails. That is the point in the amp the goes up to positive, then swings back towards the negative.
This is the only example of this type of output stage that I have ever seen used.
Is there a story behind this design.
Any way . . . . . I am curious if you had anything to do with the electronics side of Acoustat. In the 80's Acoustat offered a power amplifier.
What was different was the output stage. It was mosfets in a push -pull configuration. The sources are tied together is what looks like a conventional sources (or emitters) tied together to make the +, red, hot, not the ground, output terminal.
Instead, acoustat GROUND the source to source, junction. (aka positive speaker terminal of most other amps) You would think that nothing will come put of the amplifier, after all ground to ground. But they somehow let what would be the ground (aka black, ground, negative) speaker terminal, that swings up and down the rails. That is the point in the amp the goes up to positive, then swings back towards the negative.
This is the only example of this type of output stage that I have ever seen used.
Is there a story behind this design.
There was an Acoustat Transnova whitepaper, but in a brief search I was not able to find it. However, I did find this explanation of the Transnova concept, which I believe is based (or perhaps even copied from) the original whitepaper. Note that some later Hafler amplifiers, also designed by Jim Strickland, used the Transnova design. That's all I have to say on the subject. See https://www.tubecad.com/2024/02/blog0597.htm
Chuck - when I have more time, I will offer some suggestions for upgrading your Spectra 1100s. The good news is you should NOT have to spend anywhere near $500-600.
Edit - have you noticed any degradation in performance, or are you just looking for possible upgrades?
Edit - have you noticed any degradation in performance, or are you just looking for possible upgrades?
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Hi Mr. Acoustat, I would like to have a friend who does woodwork make me bases for my 1+1's and 2+2's. The 2+2's are the small cube. Can you (or anyone feel free to chime in!) reply with dimensions and measurement , also for drill holes and what diameter. What thickness (or type wood) is suggested to prevent warping? Your pictures of bases are just beautiful...
Good evening, jumpright:
Mr. Acoustat, Andre Sevigny, passed away back on April 15, 2015(?). He had started an couple of Acoustat threads on Canuck Audio Mart (plus others on different audio sites/forums)., titled "Acoustat's proud owners" and "Show Off Your 2 Channel Installation". The thread is still ongoing (evolving/revolving?) and is a legacy to his contribution and his fervour for Acoustat loudspeakers in general and his beloved modified 1+1s. I think the person behind the mods is(/was?) a fellow Quebecois and a friend of his, named Jocelyn. Jocelyn (Jeanson (?)) had the only highly modified Spectra 8800s. (If ones performs an Internet search, there should be remnants of Jocelyn's work here and there on Acoustat loudspeakers.) Only communicaated with Jocelyn regarding the approximate pricing of his mods/work. Not sure if Jocelyn has also passed (December 1, 2023?) or is still alive and active.
Thanks.
Sincerely,
Kingsley.
Mr. Acoustat, Andre Sevigny, passed away back on April 15, 2015(?). He had started an couple of Acoustat threads on Canuck Audio Mart (plus others on different audio sites/forums)., titled "Acoustat's proud owners" and "Show Off Your 2 Channel Installation". The thread is still ongoing (evolving/revolving?) and is a legacy to his contribution and his fervour for Acoustat loudspeakers in general and his beloved modified 1+1s. I think the person behind the mods is(/was?) a fellow Quebecois and a friend of his, named Jocelyn. Jocelyn (Jeanson (?)) had the only highly modified Spectra 8800s. (If ones performs an Internet search, there should be remnants of Jocelyn's work here and there on Acoustat loudspeakers.) Only communicaated with Jocelyn regarding the approximate pricing of his mods/work. Not sure if Jocelyn has also passed (December 1, 2023?) or is still alive and active.
Thanks.
Sincerely,
Kingsley.
Hi guys,
Wanted to ask for an opinion on the Aragon 4004 (not the MK II) for use with our Acoustats. I have never run my 2+2's on anything else so no comparison experiences. I also have a pair of 1+1's, also with the red medallion upgrade. Can I expect the Aragon to handle those? I have always wanted to get an informed opinion on this, please fire away! Any info on your experiences and if you think the amp is sufficient is very appreciated.
Wanted to ask for an opinion on the Aragon 4004 (not the MK II) for use with our Acoustats. I have never run my 2+2's on anything else so no comparison experiences. I also have a pair of 1+1's, also with the red medallion upgrade. Can I expect the Aragon to handle those? I have always wanted to get an informed opinion on this, please fire away! Any info on your experiences and if you think the amp is sufficient is very appreciated.
Hi,
My question has to do with the 3 and 3M models.
Which came first? Which is the “better” model?
What might be a reasonable price for each on the used market?
I have both to choose from in my area.
Thanks!
My question has to do with the 3 and 3M models.
Which came first? Which is the “better” model?
What might be a reasonable price for each on the used market?
I have both to choose from in my area.
Thanks!
The Acoustat Model 3 came first, and actually existed in several different variations, some of which may have been introduced after the Acoustat Model 3M. The Model 3 (in all its variations) is a full range ESL. The Model 3M could be built as a full-range ESL, or as a limited-range ESL with a woofer system for the low-end, in which case it was known as the 3 MH. There's nothing wrong with the 3M compared to the 3, they are essentially the same speaker inside. It's just the idea of being offered in two different configurations that didn't last long. The bigger question is what upgrades may have been done (including the factory Medallion transformer upgrade) that will affect sonics and price. There is also cosmetic condition and possible degradation in performance that may have occurred over time. Acoustats are extraordinarily reliable and long-lived, but nothing lasts forever. You really need to evaluate each speaker in its present state. I won't attempt to give you a price range, as it is affected by so many factors. It all depends on whether you want it bad enough and what's worth it to you, which can be said of any used purchase.
Thanks much for your thorough response. I haven’t seen any upgrades to the speakers in question, but I’ll ask. I’ve heard Acoustats over the years. Stereo Studio, a Chicago store back in the 80’s and 90’s which I visited often had them. On one occasion I started off listening to KEF 105.2’s which I consider nice and laid back for a box speaker. Then the sales person played the same music on either the 1+1’s or 2+2’s. No hash in the treble this time. Sublime!
Mr. answer man. I'm looking to upgrade the Spectra 1100 as they are pretty old and have gotten a lot of use since I bought them new. I still love the way they sound but wonder if I an missing some. I also have Polk LSiM 707's which are excellent as well as some JosephAudion RM25si MK2 for jazz.
@AcoustatAnswerMan:
Just in case you can comment on this question....
I reads through a bunch of Jim Strickland's notes & schematics on the early Acoustat TNT Transnova amps (TNT-200, TNT-120) while comparing to the later Hafler Transnova versions (9500/9300, 9505/9303 - I just care about the Hafler Transnova designs that use Lateral MOSFETs). Some of Jim's earlier Transnova papers describe "complementary" feedback, which looks to be essentially positive feedback being applied to perform some error correction/cancellation. It looks like that aspect of the unique feedback arrangement was phased out of the Hafler designs. It is R26 in the TNT schematic snippet (blue) attached. A similarly located resistor is not present in the Hafler version (yellow attached schematic snippet).
Although both driver circuits are able to pump quite a bit of current into the MOSFETs (at least 40mA), I have read that Hafler front end was supposed to be more linear than the Acoustat front end. So, was the complementary feedback dropped because it was viewed as unnecessary with the new driver circuit or were there other reasons?
I'm just curious ... I've heard the Hafler versions and liked them but have never heard the Acoustat versions ...
Sorry if this forum is ONLY about Acoustat speakers. I guess the moderators will spank me and move this ...
Just in case you can comment on this question....
I reads through a bunch of Jim Strickland's notes & schematics on the early Acoustat TNT Transnova amps (TNT-200, TNT-120) while comparing to the later Hafler Transnova versions (9500/9300, 9505/9303 - I just care about the Hafler Transnova designs that use Lateral MOSFETs). Some of Jim's earlier Transnova papers describe "complementary" feedback, which looks to be essentially positive feedback being applied to perform some error correction/cancellation. It looks like that aspect of the unique feedback arrangement was phased out of the Hafler designs. It is R26 in the TNT schematic snippet (blue) attached. A similarly located resistor is not present in the Hafler version (yellow attached schematic snippet).
Although both driver circuits are able to pump quite a bit of current into the MOSFETs (at least 40mA), I have read that Hafler front end was supposed to be more linear than the Acoustat front end. So, was the complementary feedback dropped because it was viewed as unnecessary with the new driver circuit or were there other reasons?
I'm just curious ... I've heard the Hafler versions and liked them but have never heard the Acoustat versions ...
Sorry if this forum is ONLY about Acoustat speakers. I guess the moderators will spank me and move this ...
mlloyd1 - I can't give you an answer. Both the Acoustat Transnova and Hafler Transnova were designed by Jim Strickland, who unfortunately is no longer with us to provide insight about the design decisions he made. The Hafler Transnova was certainly an outgrowth of the original Acoustat models, and in fact, was originally intended as a "next generation" for the Acoustat line. When the decision was made not to continue the Acoustat electronics line, the work was transferred and completed under the Hafer banner.
Thanks, I knew it was a stab in the dark. i'll be playing around prototyping in my free time, anyways.
I will probably poke this question around in the solid state amp forum here and see what bites I get. Just wanted to see if you might have heard any hallway chatter or seen anybody's whiteboard scribblings, etc. on Transnova circuits.
👍
I will probably poke this question around in the solid state amp forum here and see what bites I get. Just wanted to see if you might have heard any hallway chatter or seen anybody's whiteboard scribblings, etc. on Transnova circuits.
👍
just wanted to share a couple of papers I've found over the years. there are also the Transnova patents to read through as well.
Thanks for posting those documents. Both were published after I left the company, so I never saw them. FYI, I drew both of the schematics you presented above. The Acoustat schematic was hand-drawn on vellum sometime after the introduction of the line, as a publishable schematic didn't exist before then. The Hafler schematic was done in AutoCad, illustrating the change in technology available to engineers during the late 80s - early 90s. I still have a fondness for hand-drawn schematics. And yes, I heard plenty of "hallway chatter", as Jim had a real penchant for "trapping" unsuspecting coworkers into long discussions about his current work. I think explaining things helped Jim to better understand what he was doing. But unfortunately, that was over 35 years ago, and very little of it "stuck" in my head. I also remember Jim having hours-long telephone conversations with Ed Meitner and Bill Conrad.
Hi all,
I am looking into new base platforms for my 2+2's (smaller interface). The original owner replaced the originals with a thin plexiglass. I am exploring black walnut wood and have found a lumberyard that can supply plates that are solid, not glued, pieces of 22.5 x 17 x 7/8". I was told that the wood could misshape over time from humidity and to have something under them to allow air flow to prevent that.
What are your opinions or experiences? Is the 7/8" thick enough? I would think so.. I wouldn't want to do a spike as I am sure I will want to freely move them to experiment with placement. They are currently not setup, the interfaces are with Russ Knotts for inspection as I have not run them since the early 2000's.
I am looking into new base platforms for my 2+2's (smaller interface). The original owner replaced the originals with a thin plexiglass. I am exploring black walnut wood and have found a lumberyard that can supply plates that are solid, not glued, pieces of 22.5 x 17 x 7/8". I was told that the wood could misshape over time from humidity and to have something under them to allow air flow to prevent that.
What are your opinions or experiences? Is the 7/8" thick enough? I would think so.. I wouldn't want to do a spike as I am sure I will want to freely move them to experiment with placement. They are currently not setup, the interfaces are with Russ Knotts for inspection as I have not run them since the early 2000's.
The original bases were 3/4" MDF, with a plastic laminate veneer, in a variety of colors. A solid wood base could be problematic, due to the potential for warping (with most of the weight being in the center), and no doubt very expensive for a slab that big. I would explore using MDF or a high-ply plywood, with a real wood veneer if you want it to look spiffy. You can make it as thick as you want, provided you have the ceiling height! Hint: a plastic laminate on the bottom surface will make for easy sliding and good durability.