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About teknofossil

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  1. teknofossil

    Restoration - replication of 2/3 a set of a early 901 system

    Does anyone have any idea who supplied the grille cloth for the original 901 systems. I know this is a "stretch" for someone to recall something trivial like this. I have the original grilles but to help match something but I'm looking to narrow my search.
  2. teknofossil

    Improving Bose 901s

    I had a set of Ohm Model G used from a strange fellow who had a used audio shop in Northampton MA. Had a lot of bass with the upper ranges tilted downward, balance wise. I had the equalizer which actually compensated for this sonic effect, decreasing the bass and increasing the upper ranges using a 3 position slide switch. A friend in Wilbraham MA bought them from me in the early 80's. I recently asked him about them. Apparently the foam surround rotted and they made rattling sounds. He jokingly said I can have them back if I want to dig down through 20 feet of trash in the local land fill.... As my wife's English nurse says: "Bugger"
  3. Ok, I am a fan of long gone original New England audio manufacturers. After all, I'm a New Englander so there is some "home team pride" that has it's hooks into me .(FYI I am a techno geek of sorts and have little interest in Red Sox, Patriots, Celtics, the Big E and so on...only audio / historical cool stuff like Springfield made Indian motorcycles, Gee Bee race planes, Rolls Royce cars, one of the first commercial radio stations, WBZ in the US, all those computer and electronic companies). I have been a fan of the Bose 901 (along with 3 way AR's and Allisons) for a long time. No, I don't believe it is "the best" as some early adverts from Bose would suggest but they were a cool concept, still are actually and despite the nay sayers when set up as recommended, when operated within the power capabilities of the amplifier and the equalizer is operating properly and in spec they sound impressively good. A few years back while poking about on Ebay I spied an original Bose 901 equalizer. Bid low and won it, thinking I'd maybe do something with it and a pile of series 2 drivers I had siting in my storage room. But all of it ended up collecting dust as other projects came up. Moving on a few years this past October I saw a single original 901 with a few dead drivers for 50 bucks. So, I have decided to copy the cabinet, utilize the series 2 drivers, restore the equalizer and then perhaps give the completed system to my brothers son who is somewhat of a retro tech guy. Below is the original system with the drivers removed. With a set of verniers and gauge blocks I determined the original 901 cabinet side walls were 1/2" plywood. Angled rear panels are also 1/2" plywood. Front panel is 3/4" ply. Top and bottom panels are 3/4" total thickness, veneered particle board, both sides of each panel. Linen covers the front and rear of the fiberglass filling inside the cabinet. Turns out the equalizer is very early production. Some indications of this are Philips head screws to hold the RCA jack assemblies to the chassis, date codes on some of the caps appear to show 1967 mfg dates and the transistors are the early 2N3393 types (later were 2N5088). There were 2 versions of the original 901 circuit board according to the Rainy City Audio website. Below is the initial production board per their info. More later...
  4. teknofossil

    Allison 6 (CD6) tweeter health/repair question

    My concern would be that since these were crushed by impact with some object-surface, was there damage to the voice coils / formers ? No way of knowing by looking at them. Personally I'd be asking for a refund and my money back unless the seller was willing to return a serious amount of cash. Considering what it would cost to put these systems right. Just look at the prices of Allison tweeters on Ebay.
  5. teknofossil

    Carl Richard (Carlspeak) RIP 11-11-2017

    Carl helped me out with a few projects over the past few years and rescued me when I couldn't log into my Classic Speaker Pages account. I visited him a couple times in the last few years to listen to some of his projects and adopt his AR3a's that were used to develop his own upgrade to that model AR. I will miss him. GOD speed Carl. -T
  6. teknofossil

    AR-1 and Janzen ES tweeter array

    So the internal crossover of the stock AR1 and the crossover built into the Janszen module compliment each other? -T
  7. Does anyone happen to have a crossover schematic for this famous combo? Thanks! -T
  8. teknofossil

    Blumlein Stereo

    Since we are discussing system placement I thought I'd offer up this concept suggested by Ted Jordan. I tried it with some small EPI systems and it seems to work quite well. When I experimented with this set up I found that a more defined sense of depth, image specificity could be had by placing sound absorbing material on the wall in between the systems. Logic here being the sharp inward angle resulted in more reflected upper frequency sound waves from the wall, effecting the stereo imAGE. Give it a try. -T
  9. teknofossil

    AR3a and AR5 grille frames

    Sweet! Why thank you very much XPAT! -Tom
  10. teknofossil

    AR3a and AR5 grille frames

    Hello All, I have been away for a bit due to ill family members. I finally have a bit of time to myself to re-engage my AR restoration and cloning projects. Two of my projects, restoration of a pair of AR-3a's and a set of AR-5's have no grilles. So, I was wondering if anyone has the factory B/P of the original frames which they could share with me. Thanks! -T
  11. I know many of the original models, the 2a's, 2ax's, the 3's, 3a's and the 5's are considered classics. So this question treads close to or dips the toe over the line as sacrilege. Has anyone considered modifying the driver baffles so their pair is now mirror imaged? Just curious. Doing so would likely degrade the value as a collectors piece. Just curious what the some of the opinions might be. -T
  12. teknofossil

    AR LST and LST-2 cloning

    Here is the woofer / tweeter/midrange baffle. If anyone actually builds a clone you may want to wait until you have the actual drivers in hand if you are going to use the recommended tweeter replacement. AR used "T-nuts" on the driver mounting holes which I believe are 10-32 thread.
  13. teknofossil

    AR LST and LST-2 cloning

    Just what I want to hear Glenn. I forgot about the photos of your project. Thanks. -T
  14. teknofossil

    AR LST and LST-2 cloning

    Below is the second drawing. This is somewhat of a generalized plan as I don't have dimensions of some of the cabinet interior panel components. So builders will have to use their best judgement. I don't know if there is any horizontal bracing along the back wall given its relatively large surface. If anyone knows or perhaps is willing to remove their LST-2 woofer and the fiberglass filling and have a look, please report your findings. This drawing provides a general plan for location of the side panels on the top and bottom panels.