teknofossil

Hello everyone. For quite a few years I purchased my surrounds with reliable and very good results from Msound. Unf91 woofersortunately he has disappeared, hopefully it is retireent and not something darker. My Allison woofer surrounds prior were pretty variable. Even though sold as the correct surround often times the dimension of the surrund roll was wrong and/or the foam was too thick. Thickness issue resulting in higher fs. Perhaps with enough break in time they would settle out but my "clients" generally do not want to hear/deal with that. So my question is has anyone a recommended supplier for the 10 inch drivers as used in the AL 1,3 and 9 (I haven't had anyone approach me with IC20 woofer issues) and the 8inch drivers used in the 2, 4, 7 and 8? I don't do a lot of driver rebuilds anymore now that I retired (where most requests came from) so I haven't done a comprehensive search. Now I am looking at a set of AL 3 woofers in sorry shape. Any recommendations would be appreciated! I surely miss John at MSound. I used his last kit on a set of AR-91 woofers. He put together very nice kits which included the obvious parts (surrounds, adhesive, dust caps) plus sandpaper, cotton tip applicator, acid type brushes, a range of plastic sheet shim material in various gauges and his well documented instructions. All materials that would help the first timer quite a bit. Thanks for reading my long message! Tom

I have (4) Allison midrange drivers in functional condition and (2) Allison 10 inch woofers which are requiring a replacement of the surrounds. One of the Allison mid range is separated from its faceplate but when installed in the faceplate appears not to have a rubbing issue between the voice coil and pole pieces. It requires replacement of the magnetic fluid (often called "ferro fluid") which I will include. I will only sell the midrange drivers as a set. Woofers will also be sold as a set. These were purchased from EBay some years ago for the purpose of reserecting a set of Allison 1 cabinets which I no longer have. Please PM me to inquire further. -Tom

For what it is worth I suggest looking for one of the Parasound HCA (High Current Amplifier) series of amps. They are decently constructed and in my experience very reliable. I typically use my HCA-1000 which is rated at 120w/ch. My other regular (IE: functional) is a HCA-855 rated at 85w/ch. Both are very good (used) for the $. Also, my vintage (1977) Onkyo TX-4500 was very capable driving AR2ax systems as well as the OHM Model G (which I regret selling not so much due to the sound as for being a classic and unique design) -T

Try goof off. -T

Opel Kadett? My first car was a 1969 Kadett my senior year in high school in 1976. My brother, (who was a gifted auto body guy starting his first year at Worcester Polytech) and I thought it would be a good candidate for a custom paint job. Those bluish areas were actually a metalic blue with metalic green fishscale overspray. Whole thing was clear coated and then thin gold pinstripes to separate the colors. It looked cool at first, we were pretty pleased with ourselves. Tastes changed a year later and we added fog lights above the front bumper and repainted it to look like a Opel cross country rally car. Nothing like a 1.3 liter 4 cylinder engine with Solex carburation... Great fun.

Just for the sake of this discussion about (aged) capacitors I measured Industrial Condenser Corp wax block capacitor assemblies that came with the AR3a cabinets (but are apparently for the AR3). Caps that I believe in the AR3a cabinets are Sprague and Industrial Condenser Corp (ICC). Also, I did not record readings for capacitor "goodness" (construction, material, whether wound by a shaman at the summit of Machu Picchu during a blood moon) Actually I mean ESR and DF. I only tested for the actual value, using the schematic and printed values on the parts. Here is what I found: ICC Block #1 24uF section actual= 28.9 uf 6uF section actual= 7.0 uF ICC Block#2 24uF section actual= 26.5 uF 6uF section actual= 6.47uF ------------------------------------------------------------------ ICC "Royalitic Capacitor Long Life" 150 uF #1 actual= 135.65 uF ICC "Royalitic Capacitor Long Life" 150 uF #2 actual= 152.49 uF ------------------------------------------------------------------- Sprague "Compulytic 50 uF #1 actual= 52.99 uF Sprague "Compulytic 50 uF #2 actual= 52.38 uF -T

I ran some tests on the (3) AR 12 inch woofers I have. One is the AR1W woofer from my late uncles system, the other two are the P/N 200003 woofers supposedly from a set of AR 91 systems. I replaced the surrounds which were purchased from John at M-Sound not long before he disappeared. Please note the P/N 200003 woofers are not broken in and I would expect the Fs to decline a bit and possibly some of the other parameter to change as well. Even though I had the surround kits for a few years I only replaced them last year (2021) and have not done anything else with them other than verify they operate (with no rubbing). So a moderate grain of salt should be taken with these test results.

I don't know if this will be useful to anyone. From earlier conversations on the forum I thought I would post this information. If anything it will help illustrate the differences between some of the AR drivers produced over the years. I must say that I am pretty impressed these mid units seem to have weathered the years rather well. All are labeled. I am surprised the AR91 / AR92 drivers performaed as they did. Many drivers that contain ferro fluid change due to the migration of the oil component, thickening the fluid. I noticed this effect on the Allison midrange units I have and had in my lab. -T

IMOP, people that push in driver domes should be locked in stocks on the town common and vegetables lobbed at their heads.... -T

Hey there Pete! Those were the 200032 mids. These are the ones intended for the AR91 that used a 700hz LF to mid crossover point.

Well, that settles that. If it isn't audible...

I guess that would require measurements after installation in the AR9 to determine whether or not it would be ok. If the higher freq rolloff of the 200028 was taken into account in the crossover design it is possible using the 200032 might result in a response rise in the lower mid to upper mid region. But, listening or even better response measurement would be the final word. -T

Since I had the drivers out I thought I would check them on DATS. I was surprised as how close these drivers were test wise, considering these units are likely 40+ years old. A unnamed EBAY vendor is offering what is stated to be OEM replacements for a range of vintage AR (3 way) systems. I would really like to see performance data before I would consider dropping 120 dollars per unit. THese will function obviously but will the system perform as it did originally. If that is the goal I would guess crossover alteration would be required. -T

Soundminded has a point about the P/N of the AR domes. I uploaded Tim Holls description of the AR91 /92. He points out the difference between the dome drivers used in the AR9 and those that were used in the 91/92. He points out that with the mid units used in the AR9 / 90 the full VC gap (both sides of the VC) have ferro fluid, raising the fs of the driver in the AR9. So likely the (stock) crossover in the AR9 would have to be altered to maintain the original response of the design if the 200032 is installed (which could also lead to other issues). I wondered what the differences were and found the Tim Holl paper in my files.

I was going through old files and ran across the prints for the LST. Unfortunately these are all I have and are of poor quality. I hope this may help to those thinking of cloning a set. If I have time I will create clear prints using these as guides and known dimensions such as those from actual drivers and published data. -T lst1systemassy[1].TIF lst1systemassy2.tiff

Just found the info in my files.

Great fun! Unfortunately some parts, like the auto transformer would be quite the mean feat to locate. That said, Roy Allison offered a suggestion eliminating the transformer and using a separate amplifier to driver the woofer which would allow proper level adjustment. I believe Mr Allisons letter and a schematic are somewhere in these Classic Speaker pages. -T

In my restoration of my AR-2a systems one issue I wanted to ask here is what might be the appropriate material to replace the damping ring on the woofer diaphragm? These aged rings are about the same rigidity as styrofoam. -T

There is an offering by a Ebay seller (Mavin)as replacements for AR speakers using the 12" woofers. These will not yield proper results, certainly with the models produced up to sale of AR in the 90's. I am not implying these are sub standard quality just that they will not work properly with AR cabinet volumes based on the published specs and not knowing how these drivers will interact with the stock crossovers. Only AR drivers will work correctly "dropped in". I bring this up because I have had a few altered AR systems brought to me with such things as Radio Shack drivers and venting ports added. These persons want them restored to as close as possible to original condition... AR drivers as you likely know are most often pretty expensive. Questions I have had to answer time and again involve buying units from Ebay, Amazon and other sellers making various claims about being correct replacements (and being less than half the price). -T FYI: this is a hobby for me. I enjoy the work, the road to hopefully hear for myself what high performance for the time(s) would have been like. I also try to spread my enthusiasm for these old systems and often end up restoring nice old systems to save them from the trash heap. Most often only asking for the cost of parts.. Love this stuff.

No, this is the only full intact AR2A cabinet. Interesting observation is that one of the altered cabinets was built by the same cabinet maker, although about 1 year later. (Makers ID is stamped on the interior wall). -T

I enjoyed reading his comments and insights. He will be missed. -T

My mistake for the use of the term "consensus". What I meant was if there was interest I would be willing to put some of the information found in the library (provided not copyrighted or violating someone elses research material) up on a separate web link so that additional material could be made available to those interested. I did not ask Mark about altering the library. He is a busy person with other responsibilities. -T

Thank you Tom for the article. I immediately sent it to my friend who just bought a pair of AR9 from a gentleman in NY. We talked about the potential purchase before he made the decision. I did however warn him about the rather low WAF, which I suspect he is getting rewarded for. 😉 -T

Hello everyone, Happy New Year! There has been some discussion of the lack of updates with the forum library as well as some of the documents being presented in a format that triggers the protective oversight by some web browsers. I have a web domain which supports my late wife's wildlfife rescue in MA which I would be willing to make use of its largely unused space to host the information offered in the forum library as well as convert the files (in Adobe Flash originally uploaded by Ken Kantor) to resized images in a more conventional format. If there is a consensus by forum members and of course the admin and owner of the Classic Speaker Pages I would be happy to do this. Just as an FYI I am not familiar with working with contemporary apps / programs for web authoring so I would be of little use otherwise. I also have an enourmous library of information helpful for servicing and /or scratch building audio gear of all types which I would like to make available if there is interest. -T

Ok, how about instead of putting the esponsibility on Mark how about a simple website, administered by a few members, to upload this information? For example, similar in nature to say what Triode Electronics has offered since the late 90's for those looking for tube audio schematics? This could be linked in many places to the Classic Speaker Pages. http://www.triodeel.com/schindex.htm -T