Phase Plug design for MW65xx

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  • xschop
    xschop Posts: 4,684
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    Do they thread on like the B&W's?
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  • VR3
    VR3 Posts: 28,020
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    Focal has a hole in the pole piece and the phase plug has a insert that connects and they add glue
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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  • xschop
    xschop Posts: 4,684
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    Next up....

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  • Gardenstater
    Gardenstater Posts: 4,182
    edited September 2022
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    The one on the lower right looks like my Made In Mexico NOS MW6500 I got on eBay, even down to the whiteouted label with the "0" written in with pen.

    It will be interesting to see if they changed the VC OD to framepiece ID clearances. Oops. That's assuming you disassemble which you might not be doing.
    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: 4,684
    edited September 2022
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    Someone penned in "0" at end whereas other one clearly states 6501
    Also interesting this batch 6500's have 4 point swaged pole pieces.
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  • Gardenstater
    Gardenstater Posts: 4,182
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    xschop wrote: »
    Someone penned in "0" at end whereas other one clearly states 6501
    Also interesting this batch 6500's have 4 point swaged pole pieces.

    My label looks the same and the vestigal tabs were the same square ones and the pole piece is one piece with the dimple like that one you show. My date is Sep 1999. I figure (hope!) that they had long since run out of MW6500 labels at that point.
    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: 4,684
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    6500 on left suffered major collision and magnet shift. The cone was creased and deformed, but we'll save it.

    Now that I've had 4ea 6500's on hand, I'll machine a VC jig to protect it while I clearance the base plate ID's.

    The 6500's will absolutely need this or the suspension slop will just let them rub no matter what...

    us8uggu0d3a7.jpg
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  • xschop
    xschop Posts: 4,684
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    Burning the midnight oil. Went to the shop whilst there was no traffic...

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  • plastic_avatar
    plastic_avatar Posts: 687
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    OOOOOH!

    Yes!

    I have some Etons from 2002 that would loooove to see a Polk version.

    https://www.eton-gmbh.com/en/products/home-hifi/product-archive/product/8-47232-hex/
    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: 4,684
    edited September 2022
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    One done. 2 more to go. I calculated for 4-5 washers/shims in case Polk has taller baskets out there. I can adjust for cone surround clearance and jig adjustment...

    I used a Dremel paddle wheel sander. Took about 5 minutes to clearance to 1.085" ID nice and concentric...

    6otfenao164v.jpg

    m9hnu2al2vb3.jpg

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  • gp4jesus
    gp4jesus Posts: 1,969
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    Artist/machinist!
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
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  • Gardenstater
    Gardenstater Posts: 4,182
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    Brilliant! Did you find that any of the voice coils were cocked like mine are? you are probably sleeping zzzzzzzzzzzz
    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: 4,684
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    All 3 of these are running perpendicular. I have another 6510 apart and now I can say that besides the smaller baseplate ID, the 6500's are built exactly like 6510's and ohm out the same. I can test the suspension strength also by free-hanging the spud-jig on the VC and mic'ing the distance from top of spud to baseplate surface. They also match.
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  • xschop
    xschop Posts: 4,684
    edited September 2022
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    The 6500 with major magnet shift not only had a crease in cone, but VC was creased and slightly cocked until I took a Sharpie curved edge to it and smoothed it straight to where it clears the jig-spud. I simply pushed suspension to where base plate ID was used as the backing while smoothing it out.

    After running a test tone, I found that the spider was torn on that side too.
    I'm trying Eileens this time (suggestion by @westmassguy) and got the whole circumference re-done and set back straight.

    I'll run test tone again on this one after glue sets...

    p1z9k0lk9t00.jpg
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    wykzout1qfl1.jpg




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  • xschop
    xschop Posts: 4,684
    edited September 2022
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    4ea 6500's done...

    4sb0jfcaden2.jpg

    More CRA CRA....

    Both these ohm out at 7.9 ohms. One has sticker gone but says BD0610-A
    The other has 2 stickers. One on top says 6501. Bottom sticker says 6510. ..
    I'm just extactic they haven't shifted and don't rub....




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    Whatever they are, they're now hybrids...

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  • gp4jesus
    gp4jesus Posts: 1,969
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    What does “…more CRA CRA” mean?
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
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  • Gardenstater
    Gardenstater Posts: 4,182
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    slang for crazy
    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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  • plastic_avatar
    plastic_avatar Posts: 687
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    Do you always use like a razor to cut the dust cap off as close as possible to the cone, or have you ever pulled the cap free by peeling it off?

    The extra mw I have that I played with... I couldn't cut it right, but I was able to peel the cone off. It was slightly nerve wracking.

    So trying to gird myself to remove the 4 from the 1C today or tomorrow.
    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: 4,182
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    I took a small dia. wood dowel and sanded one end on my belt sander at an acute angle and super glue gell'd an xacto blade to it. Worked very well. I made a left hand and a right hand one but only used the one. The blade plunge cuts very well to get started.

    7ykw7rn3fgu1.jpg

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    e09cnwdvlrtr.jpg
    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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  • plastic_avatar
    plastic_avatar Posts: 687
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    Oh! I forgot you did that!

    [To Tinkercad and the 3D printer!]
    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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  • plastic_avatar
    plastic_avatar Posts: 687
    edited September 2022
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    How are you cutting flush without buggering it up? Steady hands?

    I can cut to the glue/coating, but after that its... difficult enough that one slip and I might cut the cone.

    I guess that much of a lip there might whizz a little?
    wbjafu6iy1ix.jpeg
    hscmgmbi172g.jpeg
    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: 4,182
    edited September 2022
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    Steady hands help. I actually also used a magnifier and, along with the knife I showed, I skimmed a little at a time off to get down into the glue line. I don't advise trying to get all of the glue line off, in order to not cut into the paper/pulp that is untreated.

    With the knife I showed you can get down to the glue line pretty much on the first cut, except for the area near the wires. Better to deliberately leave some margin there!

    Also (important) it is better to use a sawing motion with the blade to let it do the work rather than brute force method of pushing it too fast through the material.
    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
    · Share on FacebookShare on Twitter
  • xschop
    xschop Posts: 4,684
    edited September 2022
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    I cut right up to the base thats glued on. It actually adds to the cone stiffness and does not "whizz" at all.

    I started using the spud as a fast way to paint that small untreated area...

    This was the oddball one with white factory VC coil glue. Also have never seen this before...

    6silvs3lw37e.jpg

    mouxvxn2q7hl.jpg
    Don't take experimental gene therapies from known eugenicists.
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  • plastic_avatar
    plastic_avatar Posts: 687
    edited September 2022
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    O.k., I cut all the dust caps to right above where the coating soaks in at the base. So they all have a slight raised edge.

    Before I put in the xschop aluminum beauties, I'm trying a printed one in my extra mw. I pulled the cap away on this one, so it doesn't have the same lip as the others.

    I used the backing from the aluminum roof tape stuff I'm putting on the exterior basket frames for my shims. We shall see how it goes!
    5dh85kxwiwq6.jpeg
    4u1cjjktjprt.jpeg
    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: 4,684
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    Looks good. The most important thing is to make sure your pole-piece is concentric to the VC ID or you can be offset by shimming once done.

    What glue will you use on that plastic?
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  • Gardenstater
    Gardenstater Posts: 4,182
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    These are the shims I used. Vigoro plant labels with Frost King clear polyethylene tape additional thickness between the VC and phase plug. In the picture below the front shim has the PE tape also starting from between e and r in the word Every. Hard to see since it is clear.

    d9b8s1dcsx1i.jpg
    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
    · Share on FacebookShare on Twitter
  • plastic_avatar
    plastic_avatar Posts: 687
    edited September 2022
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    Gardenstater wrote: »
    These are the shims I used.

    Do you know the mm thickness of your shims?

    On glue:

    I used a tacky craft glue to test. I can pull/twist the plug out for other experiments, but it should be fine as a tester.
    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: 4,182
    edited September 2022
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    0.065" for the base layer which was a very flexible Vigoro plant label.
    0.012" total for the portion of shim laminated with the Frost King PE tape.

    Shim width = 0.75"
    length (total) = 2.5"
    length (pole piece) = 0.82"

    Lots of plant labels are unsuitable because too thick or too stiff. This plastic is very flexible. I had only enough for 4 shims. Haven't found any more of the 0.0065" stuff yet. I have 0.006" and 0.0085" and 0.003" (way too thin).
    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
    · Share on FacebookShare on Twitter
  • plastic_avatar
    plastic_avatar Posts: 687
    edited September 2022
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    Gardenstater wrote: »
    0.065" for the base layer which was a very flexible Vigoro plant label.
    0.012" total for the portion of shim laminated with the Frost King PE tape.

    Is that .012 inches total, laminated, or .12? Or mm? Man, I'm having trouble thinking today...
    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
    · Share on FacebookShare on Twitter
  • Gardenstater
    Gardenstater Posts: 4,182
    edited September 2022
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    plastic_avatar wrote: »
    Gardenstater wrote: »
    0.065" for the base layer which was a very flexible Vigoro plant label.
    0.012" total for the portion of shim laminated with the Frost King PE tape.

    Is that .012 inches total, laminated, or .12? Or mm? Man, I'm having trouble thinking today...

    0.012" (0.305 mm) total. The Frost King PE tape must be 0.0055" (0.1397 mm) thick.

    These are for my MW6500 drivers. If your VC ID and pole piece OD are different those dimensions may or may not be OK for you, depending upon how much difference.
    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
    · Share on FacebookShare on Twitter