Monitor 7 questions: should mid driver be mw6500 or mw6502?

Greetings all,
I just picked up a pair of Monitor 7's with Peerless tweeters. I should have noticed but did not, that one speaker has an mw6500 mid driver and the other has a mw6502 driver. I've read about the differences and wonder it anyone has/needs a swap of a 6502 for a 6500? I'm assuming these speakers should have mw6500 drivers?

I also was excited to hear the Peerless tweeters as they get so much love here. I am not hearing their excellence and wonder if it's the mismatched mids or if these old speakers need to be recapped to shine. Suggestions appreciated.

Comments

  • Gardenstater
    Gardenstater Posts: 4,652
    edited October 1
    Yeah you need both drivers to be MW6500. That MW6502 is for the 7C and Series II and is 4 ohm nominal impedance instead of 8 ohms. If some knucklehead did that who knows what else is wrong. Check for voice coil rub, cabinet sealing, proper phasing of drivers relative to each other; Black wire goes to red dot terminal and red binding post nut is the one on the left. Your Peerless are probably soldered but Make sure the black wire goes to the red dot terminal there as well.

    They definitely need to be recapped preferably with film types like Sonicap or Clarity Cap CSA and better quality resistors like Vishay/Mills. The electrolytics don't age well even though they were pretty high quality ones at the time. The ESR rises and the DF does too.
    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
  • bridawg
    bridawg Posts: 4
    Thanks for your input/response Gardenstater, I guess I'll try and be patient and shop around for a used mw6500. You are clearly more educated on the crossovers/recapping piece of these vintage speakers than I am. Is it correct to assume that the crossovers are designed for the same mid driver (6500) and it would make no sense to recap before I am able to find a 6500 to replace the 6502?
  • F1nut
    F1nut Posts: 51,550
    Since you absolutely need to upgrade the caps and resistors you might as well do it now while hunting for the MW6500.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • F1nut
    F1nut Posts: 51,550
    FYI, there's 3 of those drivers listed on eBay right now. You should buy one immediately as they don't come up often.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • bridawg
    bridawg Posts: 4
    Thanks for the heads up F1nut, I saw those on eBay but two look like a repeat ad of a seized speaker and the third looked a little iffy. I'll keep watching.
  • Gardenstater
    Gardenstater Posts: 4,652
    edited October 17
    There are three early ones from a 1978 10A part-out. These things must be getting scarcer because I see more and more of them claiming they work (wink wink) but they are still being sold as "for parts or not working". Pfft. https://www.ebay.com/itm/306553124627

    PS: It is still an unsolved mystery as far as how early you have to go to get ones with the "copper clad pole piece" that Polk touted in early brochures but removed from later brochures.
    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
  • Merchjbt
    Merchjbt Posts: 3
    edited October 23
    Link removed by Admin
    Those 6500s are mine. They work. I am parting out my early 10A that I have with a seized 6500.

    Mod note: This is not the appropriate time to post links of items you are selling. Please review the rules on our forums. Rules here
    Post edited by Ryan_Soundunited on
  • F1nut
    F1nut Posts: 51,550
    Merchjbt, you can't do that here.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • Merchjbt
    Merchjbt Posts: 3
    F1nut, what did I do that was wrong? I didn't post the link to begin with. I was just commenting that these were my woofers because someone implied that the woofers don't work (wink wink).
  • F1nut
    F1nut Posts: 51,550
    Go away
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • xschop
    xschop Posts: 5,000
    Tip: You'd be better off not attempting to glue the magnets, than scaring off potential buyers.
    Don't take experimental gene therapies from known eugenicists.
  • Merchjbt
    Merchjbt Posts: 3
    The hot glue comes off with little effort, so it's not permanent at all. Much better than the magnets shifting during shipping. From my experience, most buyers looking to purchase these woofers likely have seized woofers they are replacing.
  • Gardenstater
    Gardenstater Posts: 4,652
    edited October 22
    If you don't pack them with lots of cushioning that hot melt won't prevent shifting on a solid impact. Doesn't bond well to non porous surfaces like metal and ferrite. Also I personally wouldn't take a chance on ones being sold as "for parts or not working" but that's just me.
    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
  • Gardenstater
    Gardenstater Posts: 4,652
    edited October 24
    Here ya go. Just make sure seller says no voice coil rubbing and get them to pack with lots of bubble wrap and peanuts.

    https://www.ebay.com/itm/197797207356
    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
  • bridawg
    bridawg Posts: 4
    Thanks for sharing the link!