Inductor Orientation

Gathering parts to build a Point-to-Point for my last set of 5Jr's. Just want to make sure the inductor positions look OK and that it is kosher to have the 0.56mH MW inductor isolated by a sleeve and captured by 1/2" diameter non-magnetic alloy?

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Comments

  • F1nut
    F1nut Posts: 49,712
    Looks ok.
    Political Correctness'.........defined

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  • VR3
    VR3 Posts: 27,972
    You don't want the inductor lying flat against aluminum unless it is minimum 3/4" away
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
  • westmassguy
    westmassguy Posts: 6,850
    Keep this handy
    zbfsjld2f99k.png
    Home Theater/2 Channel:
    Front: SDA-2ATL forum.polkaudio.com/discussion/143984/my-2as-finally-finished-almost/p1
    Center: Custom Built forum.polkaudio.com/discussion/150760/my-center-channel-project/p1
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    Sonicaps, Mills, RDO-194s-198s, Dynamat, Hurricane Nuts, Blackhole5
    Pioneer Elite VSX-72TXV, Carver PM-600, SVS PB2-Plus Subwoofer

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  • xschop
    xschop Posts: 4,636
    edited March 2022
    VR3 wrote: »
    You don't want the inductor lying flat against aluminum unless it is minimum 3/4" away

    So, the Delrin sleeve thickness was only going to insulate it away from the alloy by 1/4" in drawing. I can lengthen it.. I was also wondering if the alloy center shaft was a problem?
    Keep this handy
    zbfsjld2f99k.png

    There it is, I remembered #6, but couldn't remember where we previously discussed it here. Thanks WMG!
    Post edited by xschop on
    Don't take experimental gene therapies from known eugenicists.
  • VR3
    VR3 Posts: 27,972
    edited March 2022
    In my experience, if you run the inductor perpendicular to aluminum, it makes little too no difference.

    If you run it parallel, right up on it almost cuts the value by 40%

    This reduces dramatically at 5/8 to 3/4 of an inch
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
  • VR3
    VR3 Posts: 27,972
    Alot of manufactures use brass bolts to mount inductor, I've never measured to see what effects the are and if you need to account for a change
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
  • Gardenstater
    Gardenstater Posts: 4,137
    So,........if you turn WMG supplied picture 90deg to the R, what you have in your XO is exactly like #5, which is PROBLEMATIC ?
    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
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  • VR3
    VR3 Posts: 27,972
    You wouldn't hear it
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
  • pitdogg2
    pitdogg2 Posts: 24,481
    edited March 2022
  • xschop
    xschop Posts: 4,636
    Thanks Tre, I'll play it safe and move inductor to top board and large cap underneath. I'm just trying to get the height of the assembly as low as possible.
    I appreciate everyone's input and experiences as always.
    Don't take experimental gene therapies from known eugenicists.
  • xschop
    xschop Posts: 4,636
    So mocking it up, I can get the MW inductor 1.5" away from billet plate, have perfect position to binding posts, but tweeter inductor will be only be 1/4" away from MW inductor....Or should I move tweeter inductor laterally left or right?

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    Don't take experimental gene therapies from known eugenicists.
  • westmassguy
    westmassguy Posts: 6,850
    About the best you can do with what you have, is to swap the resistor and inductor location. It sucks, but you're only other option as I see it, is to do a second tier
    Home Theater/2 Channel:
    Front: SDA-2ATL forum.polkaudio.com/discussion/143984/my-2as-finally-finished-almost/p1
    Center: Custom Built forum.polkaudio.com/discussion/150760/my-center-channel-project/p1
    Surrounds & Rears: Custom Built forum.polkaudio.com/discussion/151647/my-surround-project/p1
    Sonicaps, Mills, RDO-194s-198s, Dynamat, Hurricane Nuts, Blackhole5
    Pioneer Elite VSX-72TXV, Carver PM-600, SVS PB2-Plus Subwoofer

    dhsspeakerservice.com/
  • xschop
    xschop Posts: 4,636
    Working on getting #6 orientation and having only 2.5" tall crossover....

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    Don't take experimental gene therapies from known eugenicists.
  • xschop
    xschop Posts: 4,636
    Nothing like watching glue dry. I think I like this point-to-point method, you can adjust where needed and you don't have to scour for old x-over donors from that site that sells curb trash with added shipping....

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    Don't take experimental gene therapies from known eugenicists.
  • Gardenstater
    Gardenstater Posts: 4,137
    I think it's pretty CLEAR what you are doing here....... :p
    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
  • VR3
    VR3 Posts: 27,972
    Lookin good
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
  • xschop
    xschop Posts: 4,636
    edited April 2022
    Thanks Trey and WMG. I got it worked out finally. I can respect you guys that do this tedious work and make it look great. The solid copper tubular rivets I used worked out nicely going thru the 1/4" plexiglass with Cardas Litz 15.5g and the various capacitor and inductor lead diameters. I could have gotten it about 1/4" lower if I cut the posts down, but the suspended soundbarrier mod will still clear even the taller standing tweeter inductor. I got the tweeter resistor suspended how I needed also....

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    Don't take experimental gene therapies from known eugenicists.
  • xschop
    xschop Posts: 4,636
    edited April 2022
    While perusing the hobby store last week for more PVA gasket donor sheets, I stumbled upon these hard expanded foam cones. Wish I knew about these when I built the custom CRS's...
    I'm not sure which other Polk monitors have their X-overs directly behind a Midwoofer, but I can highly recommended doing this mod on the 5Jr's or the SDA-CRS where they do have this problem.

    I tested out the Aileens and Powergrab. Neither degrades or eats at the foam material, but Powergrab is more viscous and holds everything in position immediately.

    **EDIT** I didn't take a pic, but I did apply a layer or Powergrab between cone and sticky butyl mat to ensure adhesion to very porous cone material.

    I cut cones to 3" length so sound barrier foam will set @ 1/4 away from tweeter inductor...
    I used 5/8" open cell layer, butyl mat layer (holds the foam layers stiff/flat), 1/8" PVA foam layer, then another 5/8" open cell layer cut in @ 6.5" diameter circle...

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    Post edited by xschop on
    Don't take experimental gene therapies from known eugenicists.