Phase Plug design for MW65xx

Options
1…911131415

Comments

  • xschop
    xschop Posts: 5,838
    Options
    You're raising the bar on vintage SDA mods.
    Don't take experimental gene therapies from known eugenicists.
    · Share on Facebook
  • Gardenstater
    Gardenstater Posts: 4,945
    Options
    @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)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    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
    · Share on Facebook
  • plastic_avatar
    plastic_avatar Posts: 747
    Options
    @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 * custom 5B on a system for my Dad * Ye Olde college stereo in the garage
    · Share on Facebook
  • xschop
    xschop Posts: 5,838
    edited November 2022
    Options
    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


    Don't take experimental gene therapies from known eugenicists.
    · Share on Facebook
  • xschop
    xschop Posts: 5,838
    edited November 2022
    Options
    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.

    0ebnad2kx4j9.jpg

    qfi70v3ot3yr.jpg

    fsfl022anv02.jpg



    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
    Don't take experimental gene therapies from known eugenicists.
    · Share on Facebook
  • xschop
    xschop Posts: 5,838
    edited November 2022
    Options
    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

    bbamjth562k2.jpg

    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





    Don't take experimental gene therapies from known eugenicists.
    · Share on Facebook
  • plastic_avatar
    plastic_avatar Posts: 747
    Options
    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 * custom 5B on a system for my Dad * Ye Olde college stereo in the garage
    · Share on Facebook
  • xschop
    xschop Posts: 5,838
    Options
    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

    Don't take experimental gene therapies from known eugenicists.
    · Share on Facebook
  • plastic_avatar
    plastic_avatar Posts: 747
    Options
    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 * custom 5B on a system for my Dad * Ye Olde college stereo in the garage
    · Share on Facebook
  • Gardenstater
    Gardenstater Posts: 4,945
    Options
    @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
    Onkyo A-8017 integrated
    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
    · Share on Facebook
  • xschop
    xschop Posts: 5,838
    Options
    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.
    Don't take experimental gene therapies from known eugenicists.
    · Share on Facebook
  • xschop
    xschop Posts: 5,838
    Options
    2 more 6510s and 6511's showed up. No factory sagging going on with these...

    uhqgamnou7bh.jpg

    beeb7mcx9lm6.jpg

    Don't take experimental gene therapies from known eugenicists.
    · Share on Facebook
  • xschop
    xschop Posts: 5,838
    Options
    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

    Don't take experimental gene therapies from known eugenicists.
    · Share on Facebook
  • Unknown
    Unknown
    Options
    This content has been removed.
  • xschop
    xschop Posts: 5,838
    Options
    None were. They all ohmed out correctly too.
    Don't take experimental gene therapies from known eugenicists.
    · Share on Facebook
  • Unknown
    Unknown
    edited February 2023
    Options
    This content has been removed.
  • xschop
    xschop Posts: 5,838
    Options
    I take it you won't be sending any to convert?
    Don't take experimental gene therapies from known eugenicists.
    · Share on Facebook
  • F1nut
    F1nut Posts: 52,406
    Options
    Judge ~ On the charge of murdering Polk drivers how do find?
    Jury foreman ~ Guilty your Honor.
    · Share on Facebook
  • Unknown
    Unknown
    Options
    This content has been removed.
  • xschop
    xschop Posts: 5,838
    edited March 2023
    Options
    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
    Don't take experimental gene therapies from known eugenicists.
    · Share on Facebook
  • xschop
    xschop Posts: 5,838
    edited March 2023
    Options
    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.
    · Share on Facebook
  • xschop
    xschop Posts: 5,838
    edited March 2023
    Options
    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.
    · Share on Facebook
  • xschop
    xschop Posts: 5,838
    Options
    You may consider straightening up, or F1 will ship you out lol.
    Don't take experimental gene therapies from known eugenicists.
    · Share on Facebook
  • bcwsrt
    bcwsrt Posts: 2,691
    Options
    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

    · Share on Facebook
  • F1nut
    F1nut Posts: 52,406
    Options
    xschop wrote: »
    You may consider straightening up, or F1 will ship you out lol.

    You're on your way.
    · Share on Facebook
  • BlueBirdMusic
    BlueBirdMusic Posts: 3,132
    Options
    The Expanse Speaker Universe.
    "Sometimes you have to look to the past to understand where you are going in the future"
    Harry / Marietta GA
    m9iutt1ly1yd.png
    · Share on Facebook
  • xschop
    xschop Posts: 5,838
    Options
    Be patient, I've got more modding to do. Mine and yours.
    Looks like a 4th set of M7's are about complete.

    It's now clear why there are so many closet-modders here.
    Don't take experimental gene therapies from known eugenicists.
    · Share on Facebook
  • xschop
    xschop Posts: 5,838
    edited March 2023
    Options
    pitdogg2 wrote: »
    So curious, were the voice coils burnt or bad in any way?

    Another set of 6510's showed up with magnet shift. One so bad it severed the coil lead wire (on left). I was able to scrape the dust cap glue away, lift the wire up and over enough to get it repaired with fine tip soldering iron and Cardas Quad...
    Saved from the heap or trash-Bay...

    9y7j0goaypnq.jpg

    Back 100% Concentric...

    gwv4zj3vazab.jpg

    Don't take experimental gene therapies from known eugenicists.
    · Share on Facebook
  • xschop
    xschop Posts: 5,838
    edited March 2023
    Options
    ;)
    ufnimmxlqcvt.png
    Don't take experimental gene therapies from known eugenicists.
    · Share on Facebook
  • xschop
    xschop Posts: 5,838
    edited March 2023
    Options
    Never posted this. Here's a fast way to remove a factory glued magnet without breaking it. Use exactly 0.500" alloy bar and gently wedge for pressure. Takes only 1 to 1.5min heating and you'll hear a distinct snap (Loc-Tite release). Let cool and pull magnet off by hand....

    l263xahygbd8.jpg

    zbtjw0r8t0x1.jpg

    Don't take experimental gene therapies from known eugenicists.
    · Share on Facebook