Phase Plug design for MW65xx

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  • xschop
    xschop Posts: 4,697
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    Can report that the $1.25 Store fabric paint is the same type paint as the Made By Me latex window paint I've about run out of...

    4iw64yr9rhaa.jpg

    Don't take experimental gene therapies from known eugenicists.
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  • plastic_avatar
    plastic_avatar Posts: 690
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    Matting and foaming are done.

    Commence with the plugging!!!

    kzzzigl4i22p.jpeg

    Thank you xschop and Gardenstater.
    The Thrifty Setups in Mah House Big thrifty stereo in the basement w/ my custom SDA-1C (built with help from kind forum members) * Beautiful 1966 MCM GE console upgraded w/ Bluetooth, Dual turntable, and Paradigm speakers in family room * Swanky 1980 Realistic system and great TEAC eq with dancing colored lights in the living room * Ye Olde college stereo in the garage
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  • xschop
    xschop Posts: 4,697
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    You're raising the bar on vintage SDA mods.
    Don't take experimental gene therapies from known eugenicists.
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  • Gardenstater
    Gardenstater Posts: 4,184
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    @plastic_avatar do the shims fit your drivers with a nice slip fit between the pole piece and your voice coil formers, or do you think they need to be thicker? They fit my 6500s perfectly.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
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  • plastic_avatar
    plastic_avatar Posts: 690
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    @Gardenstater I think they're fine. Snug fit.

    @xschop From your workbench to my hands, master artificer.
    The Thrifty Setups in Mah House Big thrifty stereo in the basement w/ my custom SDA-1C (built with help from kind forum members) * Beautiful 1966 MCM GE console upgraded w/ Bluetooth, Dual turntable, and Paradigm speakers in family room * Swanky 1980 Realistic system and great TEAC eq with dancing colored lights in the living room * Ye Olde college stereo in the garage
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  • xschop
    xschop Posts: 4,697
    edited November 2022
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    The 11's have landed. Finally got ahold of a set of Original 6511's to plug.

    Took some measurements and they both test out at 3.5 ohms.

    These two units' magnets are actually centered in relation to pole-piece, so I won't disassemble.
    However, the spiders and surrounds are the exact same as a 6510. I did a quick depth measurement using my alloy VC jig and the suspension matches the 6510's as well.

    So my final conclusion is a I suspected, that the 6511 is a 6510 (6.5 ohms) but with a 3.5 ohm voice coil.

    The 6502 is a 6511, but with a tighter suspension/thicker weave spider, sharing the same 3.5 ohm voice coil...

    9ympdze0zuvi.jpg

    Same transparent woven-mesh dust cap...

    esdneivaf07f.jpg


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  • xschop
    xschop Posts: 4,697
    edited November 2022
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    Went ahead and cut frame tabs, glued magnets and butyl matted the frames, then cut dust caps and made matching felt rings. These will accompany some felt-ringed 6510s for an "XS-CRS-TL" build.

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    Almost every vintage driver has the terminals loose on frame.Some terminals can dangerously teeter towards frame and can let the magic smoke out. I let a small amount of Super Glue wick between tab and frame and they lock up solid...

    tmcubngy2uo1.jpg
    Post edited by xschop on
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  • xschop
    xschop Posts: 4,697
    edited November 2022
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    6511's are done...

    3jrrc632bjmi.jpg


    Another piece of the MW puzzle that's solved for me . The 6510's and 6511's, when stored face-up for a long time, have their strokes settle close to bottom and the spiders will developed a "memory" so to speak. They'll settle about 1/8" down. But I'm sure once mounted in sealed enclosures, they'll settle back to center.
    Just an observation, maybe some seasoned members have experienced?

    pwtzibp98n61.jpg

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    So to help them along, I run a hair dryer on low for about 10 min. each while they are setting on felt rings. They settle almost close to center again...

    cyrnzvn8s3ww.jpg





    Post edited by xschop on
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  • plastic_avatar
    plastic_avatar Posts: 690
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    Damn, those look nice. Is the cone material different than my 1C drivers?
    The Thrifty Setups in Mah House Big thrifty stereo in the basement w/ my custom SDA-1C (built with help from kind forum members) * Beautiful 1966 MCM GE console upgraded w/ Bluetooth, Dual turntable, and Paradigm speakers in family room * Swanky 1980 Realistic system and great TEAC eq with dancing colored lights in the living room * Ye Olde college stereo in the garage
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  • xschop
    xschop Posts: 4,697
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    Same cone material and doping compound from all other MW65xx's I've done. Judging by some drivers' sloppy application of it, the tech that day was probably on a special doping compound lol.

    And this is what they should look like when set back to center...

    luprukpz5t4m.jpg

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  • plastic_avatar
    plastic_avatar Posts: 690
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    And in all that awesome up there, a little section to add to my modding chores:

    "Almost every vintage driver has the terminals loose on frame. Some terminals can dangerously teeter towards frame and can let the magic smoke out. I let a small amount of Super Glue wick between tab and frame and they lock up solid..."
    The Thrifty Setups in Mah House Big thrifty stereo in the basement w/ my custom SDA-1C (built with help from kind forum members) * Beautiful 1966 MCM GE console upgraded w/ Bluetooth, Dual turntable, and Paradigm speakers in family room * Swanky 1980 Realistic system and great TEAC eq with dancing colored lights in the living room * Ye Olde college stereo in the garage
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  • Gardenstater
    Gardenstater Posts: 4,184
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    @xschop Does the pole piece height and magnet height vary at all across the range of MW65xx that you have measured?
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
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  • xschop
    xschop Posts: 4,697
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    Gardenstater wrote: »
    @xschop Does the pole piece height and magnet height vary at all across the range of MW65xx that you have measured?

    No. They are all the same. With the dust cap removed, you can run a straight edge across top of frame and measure to top of pole-piece.
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  • xschop
    xschop Posts: 4,697
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    2 more 6510s and 6511's showed up. No factory sagging going on with these...

    uhqgamnou7bh.jpg

    beeb7mcx9lm6.jpg

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  • xschop
    xschop Posts: 4,697
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    Their complement drivers showed up. Magnets not locked up thankfully.

    The 6511 pair are not showing any suspension sag here either...

    0ydg2dw8make.jpg

    7vm6jlablxdu.jpg

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  • pitdogg2
    pitdogg2 Posts: 24,575
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    So curious, were the voice coils burnt or bad in any way?
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  • xschop
    xschop Posts: 4,697
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    None were. They all ohmed out correctly too.
    Don't take experimental gene therapies from known eugenicists.
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  • pitdogg2
    pitdogg2 Posts: 24,575
    edited February 2023
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    Rob,
    One of the rarest woofers that many need and would pay top dollar for. I'm sorry but I find this to be horrendous that you are murdering them.

    You're a excellent machinist and I give you high marks for the things you have created, for example the tweeter plates, work of art !

    I just cannot get onboard with this on drivers that are so desirable and rare.
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  • xschop
    xschop Posts: 4,697
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    I take it you won't be sending any to convert?
    Don't take experimental gene therapies from known eugenicists.
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  • F1nut
    F1nut Posts: 49,799
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    Judge ~ On the charge of murdering Polk drivers how do find?
    Jury foreman ~ Guilty your Honor.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • nooshinjohn
    nooshinjohn Posts: 25,098
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    xschop wrote: »
    I take it you won't be sending any to convert?
    In some cases, what you are doing is no different than swapping an original 426 Hemi for a Chevy LS in a one of one ‘Cuda… Some of these drivers are incredibly hard to find any longer.
    The Gear... Carver "Statement" Mono-blocks, Mcintosh C2300 Arcam AVR20, Oppo UDP-203 4K Blu-ray player, Sony XBR70x850B 4k, Polk Audio Legend L800 with height modules, L400 Center Channel Polk audio AB800 "in-wall" surrounds. Marantz MM7025 stereo amp. Simaudio Moon 680d DSD

    “When once a Republic is corrupted, there is no possibility of remedying any of the growing evils but by removing the corruption and restoring its lost principles; every other correction is either useless or a new evil.”— Thomas Jefferson
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  • xschop
    xschop Posts: 4,697
    edited March 2023
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    The only thing RARE about these drivers is when you find one....

    that the suspension isn't wore out,
    the voice coil set wrong/cocked from factory,
    magnet/pole-piece not concentric,
    dust caps glued offset, mold-rotted
    frame edge bent/ out of round
    or the butyl surrounds dry-rotting.
    .
    ..and to add to the list,...I have encountered quite a few where the zinc plating undergoes galvanic corrosion between their base-plates and coil winding areas causing deterioration of the coil. There's a fix for that too.

    Your one-off 'Cudas are ticking time-bombs due to their mechanical disposition and organic composition. You know that microscopic white mold eating your dust caps? It really has an appetite for the thin suspension spiders.

    Sometimes an LS is the only option, unless you enjoy polishing a garage paperweight...

    https://youtu.be/vy0eWHuWmnk
    Post edited by xschop on
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  • Toolfan66
    Toolfan66 Posts: 16,906
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    An overpriced Pacer. Still some of the ugliest cars ever made, reminds me of an upside down bathtub..
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  • xschop
    xschop Posts: 4,697
    edited March 2023
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    That was a fun Pacer that out-ran a few Vettes. The look on the other drivers' face was priceless.

    Last I heard, the new owner's kid blew out the tranny.

    Don't take experimental gene therapies from known eugenicists.
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  • xschop
    xschop Posts: 4,697
    edited March 2023
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    nooshinjohn wrote: »
    Some of these drivers are incredibly hard to find any longer.

    You mean hard to find in original working order with any resemblance of original TS parameters due to their gentrification.

    Don't take experimental gene therapies from known eugenicists.
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  • Toolfan66
    Toolfan66 Posts: 16,906
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    xschop wrote: »
    That was a fun Pacer that out-ran a few Vettes. The look on the other drivers' face was priceless.

    Last I heard, "the new owner's kid blew a tranny".

    Fixed

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  • xschop
    xschop Posts: 4,697
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    You may consider straightening up, or F1 will ship you out lol.
    Don't take experimental gene therapies from known eugenicists.
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  • bcwsrt
    bcwsrt Posts: 1,597
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    xschop wrote: »
    … microscopic white mold eating your dust caps? It really has an appetite for the thin suspension spiders.

    …

    I have one MW on each speaker that have been like this for at least 20 years.

    Some questions: If I can see it, is it microscopic? I just checked and the the dust covers of the affected drivers are still firmly attached, but will my (or have any other’s) dust covers fall(en) off due to this “eating?” Why are the ones I’ve seen this way only ever around the outside edge of the dust cover? If it also goes after the spiders, why does it not spread to the other three dust covers in each speaker, or even over the remaining surface of the affected dust covers?

    Lastly, could the answers to the above possibly be that it isn’t microscopic mold?

    I ask all this a little tongue in cheek, but also, not really.

    x54dwwwog8da.jpeg

    Brian

    One-owner Polk Audio RTA 15TL speakers refreshed w/ Sonicap, Vishay/Mills and Cardas components by "pitdogg2," "xschop" billet tweeter plates and BH5 | Stereo REL Acoustics T/5x subwoofers w/ Bassline Blue cables | Rogue Audio Cronus Magnum III integrated tube amp | Technics SL-1210G turntable w/ Ortofon 2M Black LVB 250 MM cart | Sony CDP-508ESD CD player (as a transport) | LampizatOr Baltic 4 tube DAC | Nordost & DH Labs cables/interconnects | APC H15 Power Conditioner | GIK Acoustics room treatments | Degritter RCM
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  • F1nut
    F1nut Posts: 49,799
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    xschop wrote: »
    You may consider straightening up, or F1 will ship you out lol.

    You're on your way.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."

    President of Club Polk

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  • BlueBirdMusic
    BlueBirdMusic Posts: 2,077
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    The Expanse Speaker Universe.
    "Sometimes you have to look to the past to understand where you are going in the future"


    Harry / Marietta GA
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