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Thread: $5,000 for one compression driver?

  1. #61
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    Jensen Audiotorium driver

    Quote Originally Posted by Steve Schell
    Hi Ted, that woofer is one of the smaller size Auditorium Series drivers built by Jensen in the 1930s. It was probably supplied to ERPI (many were), and likely had a round ERPI black and silver paper label attached to the flat area on the rear of the pot. Looks to me like someone repaired the original cone at some point by adding a leather surround. These cones originally had a paper hinge.
    Steve

    Thanks. I am impressed with your knowledge of these vintage drivers.

    Regards
    Ted

  2. #62
    Member Marty's Avatar
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    Quote Originally Posted by aust-ted

    VC diameter is 1",horn length about 4 3/4 inch (from where diaphragm is mounted) and horn mouth diameter 2 1/4".

    throat diameter is about 3/8".

    Ted
    Thanks, will help with driver design.

    This must be the perfect supertweeter - once again Western Electric gets it so right !

  3. #63
    Senior Member spwal's Avatar
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    http://cgi.ebay.com/ws/eBayISAPI.dll...8710&rd=1&rd=1


    single W E driver just closed on ebay. i dont understand it...

  4. #64
    Senior Member Steve Schell's Avatar
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    Working 555s have been bringing around $2,500 for years now, but this one sold for a premium. I think that this is because it is a "meshback" 555W, the very first type made. The hole in the rear of the driver that vents the back side of the diaphragm was covered with a metal mesh in these, but soon after a solid plate was fitted. I'm not sure if there is any difference in performance, but the meshbacks are sought after due to their rarity.

  5. #65
    Senior Member duaneage's Avatar
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    I wonder how many old theaters have 10K worth of tweeters sitting behind the screen?

  6. #66
    Senior Member tom1356's Avatar
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    Quote Originally Posted by aust-ted View Post
    Here are some pics of the woofer. As I mentioned earlier the model plate has been removed from the back.

    Would appreciate any further help in identifying it .

    Regards
    Ted
    Just to add a little to what Steve has said...it is a Jensen M-10. You should be able to find out more about it on the web.

  7. #67
    Member Phil Jeffery's Avatar
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    "Raycophone" Field Coil driver

    Hi Aust-Ted,

    I know this thread is old, but it's not as old as the drivers under discussion, so.....

    I have one of the ERPI/WECO/Jensen bass field coil drivers that you also have. I got this from Melbourne, and it has a rear plaque that you can see in the attached photo's. Cheeky buggers, implying this is an Australian driver! I also have a Raycophone theatre amp, so I'm happy to be getting an all Raycophone system together.

    Steve Schell, if you are reading this, could you let me know your repairer here in Sydney? I have a few names; Al Daniels, Peter Keenan, Peter Stinson....but would be very interested in someone that has specialist knowledge of these older drivers. I'm getting some wacky readings when I try to measure DCR of the field coil. Thanks!





    Regards,
    Phil

  8. #68
    Member Phil Jeffery's Avatar
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    Oh, and here's a pic of the cone with single pleat surround...


  9. #69
    Senior Member Steve Schell's Avatar
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    Phil, I sent you a PM. Raycophone also installed a fair amount of equipment made by Lansing Manufacturing Company of Los Angeles in the late 1930s. They sheared off the rivets of the Lansing badges and attached Raycophone badges, again assuring all that the goods were Australian made. Perhaps their descendants now manage hedge funds!

  10. #70
    Member Phil Jeffery's Avatar
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    Thanks Steve,

    Yeah, the Instruction and Maintenance Manual for my Raycophone Sound System refers to "the amazing new Duplex multicellular." The guff that follows pretty clearly describes Altec Lansing's 604; indeed a technical drawing labelled "Duplex Speaker Connections with Emergency Changeover", dated 1947, even shows a 604 Duplex speaker unit and N-2000-B dividing network (sans Altec reference). As far as I know the amplifier was their own however.

    Regards,
    Phil

  11. #71
    Senior Member herki the cat's Avatar
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    The film in sync with the sound ??

    Quote Originally Posted by JohnK View Post
    Not only was there a problem with high frequency noise and pops from the soundtrack, but the propagation delay differences from that little horn and the large wood horns is/was terrible, the audio equivalent of not having te film in sync with the sound.... The same problem occurred when the cone woofers were added...The "Wide Range" systems seem to have been a flop.Those little tweeters are very cute, however, I didn't think that they sounded much different than the 075, and the 075 was much easier to find. For as "rare" as these are supposed to be, they seem to show up on Eba about every other month.

    The "little horn" 597 / 596 have a beautiful, unique sound artifact due to the diaphragm 3,000Hz FS resonance, the horn flare rate, the horn length & mouth size functions. These awesome speakers saw extremely little use because they were delicate & could not compete in the 3,000 Hz spectrum with the awesome 555W drivers in the WECO big 12 &15 model horns. ERPIE Service technicians hated these Bostic Tweeters. They cut them loose & just left them back stage to gather dust. I acquired a number of these when no one could have cared less 40 years ago.

    The main problem in the 1930's with "not having the film in sync with the sound" was due to the original "Cast-Iron Encased" WECO Telephone-Grade Audio Transformers used in Theater Amplifiers resulting in very poor phase shift properties. This problem surfaced in Tap Dance scene foot work "out-of-sync with the tap dance shoe clicks." ERPIE/Altec Lansing solved this problem around 1941 with introduction of new their "20 to 20,000 Hz" Transformer Amplifiers. herki[quote/]

  12. #72
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    Awesome

    The only thing "awesome" about those drivers is the fact that anybody would actually pay good money for them. The 555 is horrible sounding, and attributing the the phase differences
    to transformers is absurd.

  13. #73
    Senior Member herki the cat's Avatar
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    Quote Originally Posted by JohnK View Post
    ;The only thing "awesome" about those drivers is the fact that anybody would actually pay good money for them...Attributing the the phase differences to transformers is absurd... and the 555 is horrible sounding.

    THE FIRST ISSUE: ___I Invite you to read John K. Hilliard's history regarding Amplifier phase shift; Courtesy ©2000 Don Mc Rigtche based in part on a 1980 interview by John Eargle, @ Lansing Heritage library.

    In 1933, in MGM's sound department, Hilliard's first task was a systematic review and redesign of all recording amplifiers
    . The review was intended to address the issue of phase shift in the recording circuit. This shift was in the order of 1500 degreeswhich significantly distorted speech. The solution was to use transformers with very high self inductance and relatively large coupling capacities. Transformers with these capabilities were developed by E.B. Harrison of the Lansing Manufacturing Company and this became the original connection to James B. Lansing.

    The first full-length talking picture, "The Jazz Singer," had been released the year before and there was a mad rush by all studios to develop sound motion pictures. At United Artists Studios, Hilliard was placed in charge of the recording operations for UA's first sound picture. He was responsible for all aspects of recording, monitoring and sound editing. Western Electric supplied most of the equipment used in the recording process, but they had no experience in its
    application.

    THE SECOND ISSUE:__"The WECO Hardware"__ In the original 1930's WECO "Vita Phone" Theaters, the 555 driver was used on the type 13, dedicated-Bass Horn in the larger theaters, and the type 12 & 15 "snail" horns with excellent results up to 7,500 Hz with the drive rolled off above 6,000 Hz, which became standard practice according to the " Academe of Motion Picture Arts and Sciences" to preclude film noise.

    In Hamlets scattered around the country, there were thousands of small 800 to 1,000 seat theaters with only one or two WECO type 12 horns; each horn was equipped with either one or two 555's parallel-driven by a WECO type 46-C Power Amplifier rated at only Two Watts output from a pair of WECO "205-D" vacuum tubes. There were at least five antique cast-iron clad audio transformers in this chain including a type 49-A film sound pre-amplifier ahead of the 46-C.

    You can't get mad at a 555. Think about it!

    In the very begining there was a "three cabinet system" consisting of a type 41-A pre amplifier ahead of a type 42 A push-pull 205-D Tube, 2 watt power amplifier, followed by type 43 A, 10 watt push-pull WECO 242-C Tube power amplier stage. This system cost $30,000 in 1930; WECO hardware & ERPIE/Altec Service Co., support was available only on a lease basis.

    For small theaters, a type 41 A Pre-Amplifier cabinet plus a two watt type 42-A power amplifer cabinet was extrmely expensive, compared to the simple type 46-C Ampilier @ $10,000. In 1950, I watched a Philadelphia "Theater up-grade" dumpster loading event of a 200 Watt WECO Type 10 power amplifier with 8-B & 9-A preamplifiers , and a single, type 12 horn equipped with qty of nine 555-W compression drivers, on a mulTi-head throat.


    John K. Hilliard
    John K. Hilliard was one of the most accomplished acoustical engineers of the past century.... Hilliard was born in 1901 at Wyndmere, North Dakota. He received a B.S. in physics at Hamlin University in St. Paul Minnesota in 1925 and a B.S.E.E. at the University of Minnesota.


    © and Courtesy Todd White

  14. #74
    Senior Member herki the cat's Avatar
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    Amplifier phase shift: Courtesy ©2000 Don Mc Rigtche based in part on a 1980 interview by John Eargle, @ Lansing Heritage library.

    In 1933, in MGM's sound department, John K. Hilliard's first task was a systematic review and redesign of all recording amplifiers
    . The review was intended to address the issue of phase shift in the recording circuit. This shift was in the order of 1500 degreeswhich significantly distorted speech. The solution was to use transformers with very high self inductance and relatively large coupling capacities. Transformers with these capabilities were developed by E.B. Harrison of the Lansing Manufacturing Company and this became the original connection to James B. Lansing.

    The first full-length talking picture, "The Jazz Singer," had been released the year before and there was a mad rush by all studios to develop sound motion pictures. At United Artists Studios, Hilliard was placed in charge of the recording operations for UA's first sound picture. He was responsible for all aspects of recording, monitoring and sound editing. Western Electric supplied most of the equipment used in the recording process, but they had no experience in its application.
    Last edited by herki the cat; 02-06-2012 at 08:59 PM. Reason: improve legibility of text

  15. #75
    Senior Member tomt's Avatar
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    looks like mr. bostwick is an ongoing influence

    the chinese copy -







    the japanese copy -




    Last edited by tomt; 03-25-2012 at 04:33 PM. Reason: 11749

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