MW6509 question

geoff727
geoff727 Posts: 546
edited January 2010 in Vintage Speakers
Does anyone know the approximate nominal impedance of the MW6509 driver that goes to the SRS2?
Thanks.
Polk SDA SRS 2
Polk RTA 15tl
Polk Monitor 7C
Polk Lsi9
Infinity RS-II (modded)
Infinity RS-IIIa (modded)
Infinity RS 2.5 x 2
Magnepan 1.6QR (modded)

System: http://forum.audiogon.com/cgi-bin/fr.pl?vevol&1290711373
Post edited by geoff727 on
· Share on FacebookShare on Twitter

Comments

  • inspiredsports
    inspiredsports Posts: 5,501
    edited April 2009
    geoff727 wrote: »
    Does anyone know the approximate nominal impedance of the MW6509 driver that goes to the SRS2?
    Thanks.

    The MW6509 is a 4ohm driver
    VTL ST50 w/mods / RCA6L6GC / TlfnknECC801S
    Conrad Johnson PV-5 w/mods
    TT Conrad Johnson Sonographe SG3 Oak / Sumiko LMT / Grado Woodbody Platinum / Sumiko PIB2 / The Clamp
    Musical Fidelity A1 CDPro/ Bada DD-22 Tube CDP / Conrad Johnson SD-22 CDP
    Tuners w/mods Kenwood KT5020 / Fisher KM60
    MF x-DAC V8, HAInfo NG27
    Herbies Ti-9 / Vibrapods / MIT Shotgun AC1 IEC's / MIT Shotgun 2 IC's / MIT Shotgun 2 Speaker Cables
    PS Audio Cryo / PowerPort Premium Outlets / Exact Power EP15A Conditioner
    Walnut SDA 2B TL /Oak SDA SRS II TL (Sonicaps/Mills/Cardas/Custom SDA ICs / Dynamat Extreme / Larry's Rings/ FSB-2 Spikes
    NAD SS rigs w/mods
    GIK panels
    · Share on FacebookShare on Twitter
  • geoff727
    geoff727 Posts: 546
    edited April 2009
    Thanks. I have one that is perfect visually and plays fine, but measures 11 ohms at 1kHz with an AC signal. I'll go ahead and assume that something is wrong with it.
    Polk SDA SRS 2
    Polk RTA 15tl
    Polk Monitor 7C
    Polk Lsi9
    Infinity RS-II (modded)
    Infinity RS-IIIa (modded)
    Infinity RS 2.5 x 2
    Magnepan 1.6QR (modded)

    System: http://forum.audiogon.com/cgi-bin/fr.pl?vevol&1290711373
    · Share on FacebookShare on Twitter
  • gdb
    gdb Posts: 6,012
    edited April 2009
    I don't know about how to measure impedance but you can contact tech support at 1-800-377-POLK for a definitive answer.:)
    · Share on FacebookShare on Twitter
  • JohnLocke88
    JohnLocke88 Posts: 1,150
    edited January 2010
    Not trying to necro a dead post, but to set the record straight; the MW6509 is a 10 ohm nominal driver.
    · Share on FacebookShare on Twitter
  • Schurkey
    Schurkey Posts: 2,104
    edited January 2010
    Isn't impedance of a driver tied to both the frequency it's tested at; AND the enclosure properties?

    So the same driver might measure differently depending on whether it's installed in the box, or tested in free-air? Or whether it's tested at relatively high or low frequency?
    · Share on FacebookShare on Twitter
  • inspiredsports
    inspiredsports Posts: 5,501
    edited January 2010
    JohnLocke88 wrote: »
    Not trying to necro a dead post, but to set the record straight; the MW6509 is a 10 ohm nominal driver.

    I was trying to learn that info about a year ago and even Eric at Polk didn't have it. He was able to provide me with the various info below. You don't have the other MW6509 specs (Is:, Vas:, Qts:, Qms:, Qes:, Sd:. Xmax:, Revc:, Znom:, Pmax) also, do you?
    I am not familiar with any of this but I have this info. I ran across some time ago. I have a whole disc of Polk info. around here somewhere in all these discs. If I run across it I will post all the info. I have. Hope there is something in here that you can use.

    Driver: MW 6500 Driver's model #.
    Brand: Polk Driver's brand name.
    Fs: 31.0000 Hz (Free air resonance)
    Vas: 2.6486 ft^3 (Compliance volume)
    Qts: 0.2190 Total Q
    Qms: 1.3000 Mechanical Q
    Qes: 0.2640 Electrical Q
    Sd: 0.0130 M^2 (Piston area)
    Xmax: 3.1800 mm (Cone excursion, linear)
    Revc: 6.5000 ohms (DC resistance)
    Znom: 8.0000 ohms (Nominal impedance)
    Pmax: 35.0000 watts maximum rated power


    Driver: MW 6501 Driver's model #.
    Brand: Polk Driver's brand name.
    Fs: 31.0000 Hz (Free air resonance)
    Vas: 2.7545 ft^3 (Compliance volume)
    Qts: 0.2790 Total Q
    Qms: 1.4700 Mechanical Q
    Qes: 0.3440 Electrical Q
    Sd: 0.0130 M^2 (Piston area)
    Xmax: 3.1800 mm (Cone excursion, linear)
    Revc: 7.7500 ohms (DC resistance)
    Znom: 8.0000 ohms (Nominal impedance)
    Pmax: 35.0000 watts maximum rated power


    Driver: MW 6502 Driver's model #.
    Brand: Polk Driver's brand name.
    Fs: 44.0000 Hz (Free air resonance)
    Vas: 1.2360 ft^3 (Compliance volume)
    Qts: 0.2790 Total Q
    Qms: 1.9700 Mechanical Q
    Qes: 0.3250 Electrical Q
    Sd: 0.0130 M^2 (Piston area)
    Xmax: 3.1800 mm (Cone excursion, linear)
    Revc: 3.5200 ohms (DC resistance)
    Znom: 4.0000 ohms (Nominal impedance)
    Pmax: 35.0000 watts maximum rated power


    Driver: MW 6503 Driver's model #.
    Brand: Polk Driver's brand name.
    Fs: 29.8600 Hz (Free air resonance)
    Vas: 3.0017 ft^3 (Compliance volume)
    Qts: 0.3100 Total Q
    Qms: 1.7680 Mechanical Q
    Qes: 0.3760 Electrical Q
    Sd: 0.0130 M^2 (Piston area)
    Xmax: 3.1800 mm (Cone excursion, linear)
    Revc: 6.5400 ohms (DC resistance)
    Znom: 8.0000 ohms (Nominal impedance)

    Just found this here at CP:

    The MW6510 is no longer available through us and the MW6503 is the substitute. It is *close* but not an exact match. Here's some of the basic differences:

    6510 vs 6503
    Q 1.82 vs 1.39
    BL 5.24 vs 6.62 N /AMP
    Compliance 3.55E-3 vs 3.41E-3 N/M
    DCR 6.54 vs 6.57 ohms
    Fs 29 vs 31 Hz.
    __________________
    -Eric
    -Polk Audio

    Will keep looking around to see if I find anything else. This also helps me learn all this stuff,lol.
    VTL ST50 w/mods / RCA6L6GC / TlfnknECC801S
    Conrad Johnson PV-5 w/mods
    TT Conrad Johnson Sonographe SG3 Oak / Sumiko LMT / Grado Woodbody Platinum / Sumiko PIB2 / The Clamp
    Musical Fidelity A1 CDPro/ Bada DD-22 Tube CDP / Conrad Johnson SD-22 CDP
    Tuners w/mods Kenwood KT5020 / Fisher KM60
    MF x-DAC V8, HAInfo NG27
    Herbies Ti-9 / Vibrapods / MIT Shotgun AC1 IEC's / MIT Shotgun 2 IC's / MIT Shotgun 2 Speaker Cables
    PS Audio Cryo / PowerPort Premium Outlets / Exact Power EP15A Conditioner
    Walnut SDA 2B TL /Oak SDA SRS II TL (Sonicaps/Mills/Cardas/Custom SDA ICs / Dynamat Extreme / Larry's Rings/ FSB-2 Spikes
    NAD SS rigs w/mods
    GIK panels
    · Share on FacebookShare on Twitter
  • JohnLocke88
    JohnLocke88 Posts: 1,150
    edited January 2010
    I do not sorry. My quest for 6509 info was based upon finding some SDA-1B crossovers on ebay relatively cheap. Was going to try a custom SDA build and then gave up after the relative impossibility of finding 6509 at reasonable prices.
    · Share on FacebookShare on Twitter
  • inspiredsports
    inspiredsports Posts: 5,501
    edited January 2010
    JohnLocke88 wrote: »
    I do not sorry. My quest for 6509 info was based upon finding some SDA-1B crossovers on ebay relatively cheap. Was going to try a custom SDA build and then gave up after the relative impossibility of finding 6509 at reasonable prices.

    Dang, I wish you had been doing this a year ago when I rebuilt and TL'd my SDA SRS 2's. I had 6 or 7 perfect extra 6509's here that I sold to CP members. At the time I think Sal had some extras also.

    I have 3 original 1986 MW6509's here that are magnet shifted that I have been keeping in case I ever need to have them repaired ($30 each at http://www.midwestspeaker.com).

    I also have all 4 pieces of SDA-1B crossovers here as they are identical to what's in an SDA SRS 2 with I think the exception of 1 resistor value.

    How many 6509's are you after?
    VTL ST50 w/mods / RCA6L6GC / TlfnknECC801S
    Conrad Johnson PV-5 w/mods
    TT Conrad Johnson Sonographe SG3 Oak / Sumiko LMT / Grado Woodbody Platinum / Sumiko PIB2 / The Clamp
    Musical Fidelity A1 CDPro/ Bada DD-22 Tube CDP / Conrad Johnson SD-22 CDP
    Tuners w/mods Kenwood KT5020 / Fisher KM60
    MF x-DAC V8, HAInfo NG27
    Herbies Ti-9 / Vibrapods / MIT Shotgun AC1 IEC's / MIT Shotgun 2 IC's / MIT Shotgun 2 Speaker Cables
    PS Audio Cryo / PowerPort Premium Outlets / Exact Power EP15A Conditioner
    Walnut SDA 2B TL /Oak SDA SRS II TL (Sonicaps/Mills/Cardas/Custom SDA ICs / Dynamat Extreme / Larry's Rings/ FSB-2 Spikes
    NAD SS rigs w/mods
    GIK panels
    · Share on FacebookShare on Twitter
  • JohnLocke88
    JohnLocke88 Posts: 1,150
    edited January 2010
    I'm not looking for any myself; gave up on the 1B project. I'm now looking for MW6500s for my RTA12s
    · Share on FacebookShare on Twitter