Monitor 10’s

Hi folks! Silly question: I picked up a pair of Monitor 10’s today and I have no idea how to tell which model? I see people discussing b’s or a’s and Peerless tweets etc... How do I tell what I have? Thanks in advance!

I did have (back in the 80’s) a pair of the Monitor 7’s and I loved them. I remember wishing I had splurged and spent the extra for the 10’s. I am so glad I finally have them. They sound amazing for being as old as they are now.

Oh, one more thing: These 10’s must have been in a restaurant or with someone that does a lot of deep fat frying. The cabinets had a sticky residue on them as well as all the drivers. What is the best way to clean these suckers?

Matt
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Comments

  • Faustin
    Faustin Posts: 1,149
    I would suggest posting some pictures of the 10's to help identifying what generation they are.
  • Gardenstater
    Gardenstater Posts: 4,135
    ^^^ Ding ding ding. Don't forget to take the grilles off.
    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
  • mhardy6647
    mhardy6647 Posts: 32,925
    Assuming the OP's 10s have Contact Paper vinyl 'veneer' ;) -- the stuff used on oh-so-many 1970s-era loudspeakers gets sticky all by itself after, oh, four decades or so. IME the Polk loudspeakers suffer less from this scourge than some others (I am lookin' at you, Epicure/EPI! :# ) but that'd be my guess (FWIW).

    As a single reference point :p, here's a very early Monitor Series Model 10 for comparison and FWIW.
    Note the uncoated paper passive radiator, "supervelcro" grille fasteners, and un-holey Peerless silk dome tweeter.

    11208619575_674f036d9b_c.jpgP1020559 by Mark Hardy, on Flickr
  • F1nut
    F1nut Posts: 49,704
    Hi folks! Silly question: I picked up a pair of Monitor 10’s today and I have no idea how to tell which model? I see people discussing b’s or a’s and Peerless tweets etc... How do I tell what I have? Thanks in advance!

    I did have (back in the 80’s) a pair of the Monitor 7’s and I loved them. I remember wishing I had splurged and spent the extra for the 10’s. I am so glad I finally have them. They sound amazing for being as old as they are now.

    Oh, one more thing: These 10’s must have been in a restaurant or with someone that does a lot of deep fat frying. The cabinets had a sticky residue on them as well as all the drivers. What is the best way to clean these suckers?

    Matt

    Welcome Matt.

    The driver cones are supposed to be sticky, do not attempt to remove the coating. The vinyl covering the cabinets can be cleaned with original Windex.

    I hate to tell you this, but the 7 is the better speaker.
    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

  • Thanks for the welcoming and for the quick responses! Here are a few pictures of the 10’s. It looks like they have different tweeters. kmge14wlpp47.jpeg
    ggxzhfcqxm1c.jpeg
    903ift7q4nco.jpeg
    aajjfidciq3w.jpeg
    z6a8geomtu9g.jpeg
  • They also have sequential serial numbers. Not sure if that makes any difference.
  • pitdogg2
    pitdogg2 Posts: 24,474
    Yes someone replaced one of the original SL2000 tweeters for the RD-0194 tweeter. The RD-0194 is a much better tweeter. I'd try to get another ASAP.
    I think those can be called monitor 10c as the next generation was called series 2 and came with the SL2500 tweeter.
  • mhardy6647
    mhardy6647 Posts: 32,925
    I assume (??) that the lack of a back-panel fuse on these Monitor 10s indicates that they have "Polyswitches" to protect the tweeters?

  • pitdogg2
    pitdogg2 Posts: 24,474
    You would be correct
  • mhardy6647
    mhardy6647 Posts: 32,925
    pitdogg2 wrote: »
    You would be correct

    Like monkeys, typewriters, and Shakespeare -- once in a while, it happens.

    :#
  • So which tweeter is the better of the two? The black one or the silver one?
  • pitdogg2
    pitdogg2 Posts: 24,474
    edited June 2021
    Black is better

    Black dome is RD-0194
    Silver SL 2000
  • Thanks! I'll order one from eBay tonight. Easy to put in? I'm not the most tech savvy guy in the world. 😄
  • mhardy6647
    mhardy6647 Posts: 32,925
    Thanks! I'll order one from eBay tonight. Easy to put in? I'm not the most tech savvy guy in the world. 😄

    four screws, two wires. :)
    That said -- I don't know whether the wires are soldered to the tweeter or if they use quick disconnects.

    27oxeiyrwvye.png


    I also don't know how the tweeter is 'sealed' into the enclosure in these -- could be a gasket, or some kind of goop. The cabinet needs to be sealed air tight for the passive radiator to do its job.

    1) folks here will know the precise answers to both "concerns" above.
    2) it ain't rocket science ;)

    You can do it! :)


  • odcics2
    odcics2 Posts: 305
    Anyone ever use a wire wound resistor in the tweeter circuit to tame bright tweeters??
    It would be easy, since you could add it to the fuse in back.

    I have early Monitor 10s, Peerless tweeters with the hole in the middle.

    I have some known hearing loss in the mid frequencies, so a balanced speaker sounds a bit bright to MY ears! And, I won't mention the tinnitus in my left ear.
  • pitdogg2
    pitdogg2 Posts: 24,474
    odcics2 wrote: »
    Anyone ever use a wire wound resistor in the tweeter circuit to tame bright tweeters??
    It would be easy, since you could add it to the fuse in back.

    I have early Monitor 10s, Peerless tweeters with the hole in the middle.

    I have some known hearing loss in the mid frequencies, so a balanced speaker sounds a bit bright to MY ears! And, I won't mention the tinnitus in my left ear.

    Or you could just up the tweeter resistor in the circuit a 1/2 ohm or so....All you're doing is making the tweeter more quiet. When we recap we (most) all use wire wound resistors instead of ceramic resistors.
  • odcics2
    odcics2 Posts: 305
    Cool.
    Thinking something in line with the fuse will work, since it’s easily reversed if I sell them.
    Thanks.
  • DaveHo
    DaveHo Posts: 3,471
    Assuming the one with the sl2000 is original, those are 10B's.
  • mhardy6647
    mhardy6647 Posts: 32,925
    edited June 2021
    I would still think/opine that an L-pad (variable or fixed) is the best wideband way to tame an unruly tweeter (FWIW).
    Fixed L-pad is just two resistors (one series, one parallel, thus the "L"), and can be constructed to match both the load impedance and the desired attenuation pretty precisely. Here's a calculator, e.g.
    http://www.sengpielaudio.com/calculator-Lpad.htm

    Variable L-pads are inexpensive and of decent enough quality. One doesn't need high power handling for a tweeter, either.
    Here's an 8-ohm, 15 watt example.
    https://www.parts-express.com/L-Pad-15W-Mono-3-8-Shaft-8-Ohm-260-248

    Just adjust by ear and stick it inside the enclosure for temporary/experimental use! :)
    or... go full-on ghetto MacGyver.

    14104855819_3fb8955d15_b.jpgIMG_0341 by Mark Hardy, on Flickr

    EDIT: derp, I forgot the new "leaving Las Vegas" Vanilla "feature" :p
    Here, we'll just use some forum bandwidth instead. :/

    mr2r1b878uwj.png


    Now, a peaky tweeter will probably benefit from a less generic, more "engineered" solution (maybe a notch filter, e.g.).

  • odcics2
    odcics2 Posts: 305
    edited June 2021
    hcna3vy3n3zt.jpeg
    mgz1y2ennng6.jpeg
    Lol, it’s my ears that are peaky!
    Good idea!

    Should have mentioned that my speakers have dual fuses in back.
    10b have those??

    When I said early, I was going by what I was told. This is my first set of Polk speakers. Newbie!!!
  • Gardenstater
    Gardenstater Posts: 4,135
    edited June 2021
    Alright now we need all the other missing info :D Could you take the crossover and drivers out and get any numbers dates off of them? 10B's I believe were the last ones before the SeriesII and they could have either SL1000 (fuse protected) or SL2000 tweeters. Correct me if this is mistaken but I think there was no 10C. Mid model 10B changes occurred some time between late 1984 and late 1985. Apparently they also went from 6600x to 6503 MW's.

    PS: I guess I was confused and see that we have two posters with Monitor 10s.
    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
  • pitdogg2
    pitdogg2 Posts: 24,474
    Them fuses look much higher than the 1 amp fast blow fuse they came with. None of my 1amp fast blow fuses had wavy filament, in fact you can barely see the darn thing.
  • F1nut
    F1nut Posts: 49,704
    DaveHo wrote: »
    Assuming the one with the sl2000 is original, those are 10B's.

    We have 2 different Monitor 10 owners posting in this thread making it a bit confusing. The poster you responded to is not the OP.
    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

  • odcics2
    odcics2 Posts: 305
    Alright now we need all the other missing info :D Could you take the crossover and drivers out and get any numbers dates off of them? 10B's I believe were the last ones before the SeriesII and they could have either SL1000 (fuse protected) or SL2000 tweeters. Correct me if this is mistaken but I think there was no 10C. Mid model 10B changes occurred some time between late 1984 and late 1985. Apparently they also went from 6600x to 6503 MW's.

    PS: I guess I was confused and see that we have two posters with Monitor 10s.

    Happen to have the back of a mid-woofer photo. 4l40atk6dis0.jpeg

  • Gardenstater
    Gardenstater Posts: 4,135
    edited June 2021
    About all we can get from that is it had a resonant frequency of 22 Hz. Must be pre paper labels. Yours have to be either 10 or 10A. I don't know which. I think I would guess 10A. If you want to keep searching for an actual date it could be narrowed down more. On the crossover PCB or on the other drivers.

    Was that driver attached gasketed sealed with Moretite?
    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
  • pitdogg2
    pitdogg2 Posts: 24,474
    edited June 2021
    That is a MW6500 George, Gasket is on the front bezal
  • Gardenstater
    Gardenstater Posts: 4,135
    edited June 2021
    OK Ivan thanks. Would've been my guess. Have you ever seen ones with no paper labels from the factory? Probably just fell off and is somewhere in the enclosure?
    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
  • pitdogg2
    pitdogg2 Posts: 24,474
    edited June 2021
    No I've not seen one myself BUT it could have happened
  • odcics2
    odcics2 Posts: 305
    No labels in the cabinets!
  • mhardy6647
    mhardy6647 Posts: 32,925
    edited June 2021
    hmm... FWIW... "557 809" looks like a standard EIA code.
    That said, I found no manufacturer assigned code "557" in the biggest list I have (albeit from 1961) -- maybe Polk? ;)
    If it is an EIA code, the driver would've been made in Week 9 of 1980 (or maybe, possibly, week 9 of 1978... but by 1978 EIA year codes used two digits AFAIK).

    EDIT: hmmmmm^2... and FWIW^2... I dug around a little more, googling EIA codes in 1980. EIA had assigned "557" to Matrecs, a company that did indeed make loudspeakers... and maybe (???) they made OEM drivers, too? I dunno. Matrecs later morphed into "MiTek Industries" which is still around and is the parent/owner of a number of second-tier "modern" loudspeaker brand names (MTX and DCM, e.g.).
    https://www.ecianow.org/assets/docs/EIAStandards/1.7.6_EIA Source Codes_1981.pdf

    is1c8nzboe0v.png