Phase Plug design for MW65xx

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  • xschop
    xschop Posts: 5,000
    3/8-16 x 2" socket head set screws are the ticket....

    w3zpfk8lsbhz.jpg
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  • pitdogg2
    pitdogg2 Posts: 25,553
    I wondered where you were going with this ....
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  • Gardenstater
    Gardenstater Posts: 4,500
    I think it's really interesting what you are doing here. Do you need to use a high magnetic permeability screw like soft iron or mild steel so as not to have the function of the magnet motor be disturbed in any way, or is the effect of using a regular steel machine screw negligible? How did you end up getting the magnet separated from the pole pieces without damage?
    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
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  • pitdogg2
    pitdogg2 Posts: 25,553
    stainless or brass would more likely be the ticket if non magnetic comes into play.
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  • xschop
    xschop Posts: 5,000
    I have some nylon ones, but the black-oxide is more aesthetic than puke-yellow hehe.

    On a serious note, this exercise convinces me that the pole-piece and magnet must also be concentric or there will be an offset of magnetic force as witnessed by the teetering pull of the steel shim. It goes away when they are true-centered.
    I've seen many of these Polk MWs where their magnets were offset, although functioning.
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  • xschop
    xschop Posts: 5,000
    edited May 2020
    I've removed and installed many tapered bearings in Porsche hubs this way.... I had to remove two layers of paper from the duct-tape inner roll. No magnets were harmed lol...

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  • Gardenstater
    Gardenstater Posts: 4,500
    edited May 2020
    Ahh so light taps with a hammer on the inner pole piece by way of a soft metal drift and the duct tape *receiver* is soft so as to not damage the magnet. Did you also use heat first to weaken the adhesive?

    How did you get the magnet plus inner pole piece separated from the pole piece that goes between the magnet and the basket?
    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
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  • xschop
    xschop Posts: 5,000
    I didn't have to use heat. The factory magnet to basket plate adhesive was so oxidized that it gave with a nice controlled hit. When apart and dipped in acetone, it sloughs right off at only a couple microns thick. It's a miracle that the second one never clicked and froze the voice coil in transit or by doing simple mods to them.
    Don't take experimental gene therapies from known eugenicists.
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  • Gardenstater
    Gardenstater Posts: 4,500
    Great thread! I'm contemplating my next move on the never ending 7B modifications. I have done Dynamat, BlackHole5, XO Sonicaps and Mills/Vishay resistors, all internal wiring and fuse block wiring Cardas Litz and Neotech solid, Cardas Binding Posts.

    Still haven't done Larry's Rings or Hurricane Nuts.

    Should I do phase plugs next? :)
    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
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  • xschop
    xschop Posts: 5,000
    Unless you disassemble magnet and drill/tap pole piece, your challenge would be to center plug via circular shim and use a double-sided 3M tape.
    Yes, you should IMO.
    Don't take experimental gene therapies from known eugenicists.
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  • xschop
    xschop Posts: 5,000
    edited January 2021
    Next weekend I'll be starting a batch of the MW backer-rings. I have the aluminum dowel on order for more phase plugs so that'll be a couple weekends before I can get to those and I'll get a set out to you if you'd like. My 8TLs will get them surely.
    Don't take experimental gene therapies from known eugenicists.
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  • Gardenstater
    Gardenstater Posts: 4,500
    Rob that's awesome! PM sent.
    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
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  • xschop
    xschop Posts: 5,000
    Peeped in to plagiarize my own work hehe.
    Working on a batch of the self-adhesive plugs.
    Don't take experimental gene therapies from known eugenicists.
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  • xschop
    xschop Posts: 5,000
    edited November 2021
    Where's Randy Croissant? I'm ready to phase-plug the SDA-2B drivers. They indeed clean-up the inverted SDA signal.
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  • xschop
    xschop Posts: 5,000
    edited November 2021
    VSAT, I know you still lurk here and heard you had some road-trip CRS+'s lol

    The new design streamlines the process. A single drop of Red Loctite 271 is all it takes. They are set by eyesight with equilateral clearance to the voice coil....

    c86tt0mu7qi8.jpg

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    Post edited by xschop on
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  • xschop
    xschop Posts: 5,000
    This is for the Enabler in Chief.... These took about an hour start to finish minus Loctite setup time. Last 2 felts are setting now...


    n46njwjd6bgc.jpg
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  • Toolfan66
    Toolfan66 Posts: 17,294
    edited December 2021
    I can honesty say that took some serious balls to do on vintage drivers, I know for a fact that is one mod I couldn't get myself to do. Awesome work bud...

    cukpqq9kmmkz.png
    Polk Audio SDA 2.3tl Fully Hot Rodded. 😎

    SVS SB16 X2

    Cary SLP-05/Ultimate Upgrade.
    Cary SA-500.1 ES Amps
    Cary DMS 800PV Network
    OPPO UDP 205/ModWright Modification
    VPI Scout TT / Dynavector 20x2
    Jolida JD9 Fully Modified

    VPI MW-1 Cyclone RCM

    MIT Shotgun 3 cables throughout / Except TT, and PC’s
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  • xschop
    xschop Posts: 5,000
    edited December 2021
    Thanks for the picturesque 'kudos' lol

    Looks like another case of gene-therapy induced epididymitis, but hopefully for him a simple case of hydrocele.

    I've done about 10-12 myself now with the newer glue-on version. After @8 hrs cure time, you can pick up the MW by the plug and install it in cabinet.

    The CNC lathe that I have the programming on took a dump (Yaskawa VFD) the first of the year and waited 7 months for a new one. I wish I were able to get a full set of these in the Monoliths before they set sail in their sarcophagi. I would have offered to do the drivers myself, but I don't make promises I can't keep.



    I made a nice batch a couple weeks ago mainly to test in 8TL-SDA hybrids to answer my own question whether it cleans up the SDA signal like it does for the stereo signal. We'll get VSAT's impression soon in a factory set of 2B's.

    For me, I'll never own another set of Vintage Polk monitors or SDA's without this modification to the drivers.

    w1tjzk6eadmd.jpg







    Post edited by xschop on
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  • Toolfan66
    Toolfan66 Posts: 17,294
    They are awesome, if the vintage drivers were more plentiful I would probably go for it, but I would hate to screw up a couple knowing finding replacements can be tough..
    Polk Audio SDA 2.3tl Fully Hot Rodded. 😎

    SVS SB16 X2

    Cary SLP-05/Ultimate Upgrade.
    Cary SA-500.1 ES Amps
    Cary DMS 800PV Network
    OPPO UDP 205/ModWright Modification
    VPI Scout TT / Dynavector 20x2
    Jolida JD9 Fully Modified

    VPI MW-1 Cyclone RCM

    MIT Shotgun 3 cables throughout / Except TT, and PC’s
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  • xschop
    xschop Posts: 5,000
    From doing this modification, I've discovered how to repair a burnt coil from an old 6502 using a new 3.8 ohm JBL voice coil replacement. So don't toss old drivers....

    https://audiomilitia.proboards.com/thread/427/more-phase-plug-mods

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  • ptrooper
    ptrooper Posts: 501
    xschop wrote: »
    Thanks for the picturesque 'kudos' lol

    Looks like another case of gene-therapy induced epididymitis, but hopefully for him a simple case of hydrocele.

    I've done about 10-12 myself now with the newer glue-on version. After @8 hrs cure time, you can pick up the MW by the plug and install it in cabinet.

    The CNC lathe that I have the programming on took a dump (Yaskawa VFD) the first of the year and waited 7 months for a new one. I wish I were able to get a full set of these in the Monoliths before they set sail in their sarcophagi. I would have offered to do the drivers myself, but I don't make promises I can't keep.



    I made a nice batch a couple weeks ago mainly to test in 8TL-SDA hybrids to answer my own question whether it cleans up the SDA signal like it does for the stereo signal. We'll get VSAT's impression soon in a factory set of 2B's.

    For me, I'll never own another set of Vintage Polk monitors or SDA's without this modification to the drivers.

    w1tjzk6eadmd.jpg







    Thank you for everything Rob. I would have also loved to have had your phase plugs installed into the monoliths .
    I also dont have the nuggets to take on that upgrade myself.
    Thinking of taking a trip down under lately ? : )>
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  • RandyCroissant
    RandyCroissant Posts: 475
    Interesting mod…
    Yamaha RXA1030, Yamaha CD-S2100, Yamaha AS-2200, Bluesound node 2i
    Polk SDA2btl highly modded
    Polk SDA 1C modded
    Polk CS350 LS x2
    Kimber 8TC
    Sony 55" Bravia
    Wish list SVS sub

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  • xschop
    xschop Posts: 5,000
    ptrooper wrote: »
    xschop wrote: »
    Thanks for the picturesque 'kudos' lol

    Looks like another case of gene-therapy induced epididymitis, but hopefully for him a simple case of hydrocele.

    I've done about 10-12 myself now with the newer glue-on version. After @8 hrs cure time, you can pick up the MW by the plug and install it in cabinet.

    The CNC lathe that I have the programming on took a dump (Yaskawa VFD) the first of the year and waited 7 months for a new one. I wish I were able to get a full set of these in the Monoliths before they set sail in their sarcophagi. I would have offered to do the drivers myself, but I don't make promises I can't keep.



    I made a nice batch a couple weeks ago mainly to test in 8TL-SDA hybrids to answer my own question whether it cleans up the SDA signal like it does for the stereo signal. We'll get VSAT's impression soon in a factory set of 2B's.

    For me, I'll never own another set of Vintage Polk monitors or SDA's without this modification to the drivers.

    w1tjzk6eadmd.jpg







    Thank you for everything Rob. I would have also loved to have had your phase plugs installed into the monoliths .
    I also dont have the nuggets to take on that upgrade myself.
    Thinking of taking a trip down under lately ? : )>

    At this point in time, I'm afraid it'd be easier for you to get some nuggets. But if 16 drivers showed up, I'd accept the challenge.
    Don't take experimental gene therapies from known eugenicists.
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  • ptrooper
    ptrooper Posts: 501
    16 drivers. That sounds like a plan
    Decommissioning a set of 1.2s
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  • xschop
    xschop Posts: 5,000
    Lol. At least take possession of them first and get a good baseline of pre-plug soundstage impressions. From what I've heard the soundstage realism improves. I can only surmise that the stereo signal is now more properly sync'd with the inverted SDA signal.

    Hopefully port ransom is manageable down-under.

    And apologies for coming off crass in my comment previously. Now if good seats to Men at Work show are in the conversation, I'm all ears.
    Don't take experimental gene therapies from known eugenicists.
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  • ptrooper
    ptrooper Posts: 501
    edited December 2021
    All good Rob,no apologies needed as no offence taken.

    I do beleive your plugs should give a better cabinet seal and improve stability within its movement.Can we make them sharper for kiddies.

    I wonder if Nooshinjohns 1.2's have sold ? Works out to be about 93 a driver including the tweets.Does John live close >:) ?





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  • xschop
    xschop Posts: 5,000
    As of now, there are only two sets 1.2's that I'd be interested in phase-plugging myself. His is not one of them.
    Don't take experimental gene therapies from known eugenicists.
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  • ptrooper
    ptrooper Posts: 501
    You've planted the seed thanks >:) Rob. :p My plan would have me buying another set but only needing the drivers.The cabinets could be used for a box and pallet for the drivers.We can fill it with 30x5 kilo box's of flour to entertain customs.
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  • VR3
    VR3 Posts: 28,732
    Lol! Love it
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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  • xschop
    xschop Posts: 5,000
    Mark half the bags for Guido and the rest for Vinny...
    Don't take experimental gene therapies from known eugenicists.
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