Polk Monitor 7 Identification

MLampen
MLampen Posts: 8
in Vintage Speakers
I'm thinking these are the latest 7C's but just want to confirm. Any thoughts? I'm looking at another pair that seem to be an earlier model and since I have two options here, I'd like to go with whatever is the better option.

Badge on grill
bevelled edges
Serial number is 7 51968
No fuse
SL2000 tweets?

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Comments

  • aprazer402
    aprazer402 Posts: 3,149
    They appear to be the 7C version, no fuse, a thermal polyswitch. They were the last iteration before the Monitor Series 2 with the SL-2500 tweeter. If the earlier version you're considering has the Peerless tweeter with one fuse on the rear, it would be the 7B. Many 7B's have a Peerless tweeter compared to the SL-2000 tweeter in the speaker in your photo. I prefer the Peerless to the SL-2000, most do. Either would sound fine. It really comes down to price and cosmetics, then you decide which sound you prefer. Buy both, compare, then sell the least favorite, if feasible.
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  • MLampen
    MLampen Posts: 8
    Thanks aprazer. Here's the other pair I'm looking at which are clearly C's as well since it says it by the serial number there. Wondering if anyone would have an opinion on which they would choose.

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  • pitdogg2
    pitdogg2 Posts: 25,576
    Personally I'd pick the pair with the sl2000 tweeter. Only reason is the replacement RD-0194 tweeter would drop right in the spot. The sl1000 tweeter is smaller and therefore woodworking on the front would be required to fit properly.
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  • Gardenstater
    Gardenstater Posts: 4,502
    edited December 2020
    Oh, so very early 7C's had the SL1000 and an external fuse block......interesting. I woulda thunk only late 7B's had the SL1000 and I didn't know that any 7C's had the fuse block. Some more info. to try to file away in the noggin.

    I wonder if the Peerless could be swapped out for the SL1000. I believe size-wise is not a problem. Question is how different the Peerless would sound and if they made any crossover changes to use SL1000 vs Peerless. Heck, we don't even know if those tweeters came with the speaker, and I have read here on the forum that SL1000 was what Polk sent as warranty claim replacements for the Peerless. Hard to say which speaker is the better way to go, and without more info. about the crossovers and drivers, a tough decision. So, you have to buy them both lol.

    PS: I believe at some point the 7 went from an 8 Ohm nom. impedance rating (7B and earlier) to 6 Ohms (7C w/ SL2000), and then (maybe) 4 Ohms.
    Post edited by Gardenstater on
    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
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  • aprazer402
    aprazer402 Posts: 3,149
    Gardenstater wrote: »
    Oh, so very early 7C's had the SL1000 and an external fuse block......interesting. I woulda thunk only late 7B's had the SL1000 and I didn't know that any 7C's had the fuse block. Some more info. to try to file away in the noggin.

    I wonder if the Peerless could be swapped out for the SL1000. I believe size-wise is not a problem. Question is how different the Peerless would sound and if they made any crossover changes to use SL1000 vs Peerless. Heck, we don't even know if those tweeters came with the speaker, and I have read here on the forum that SL1000 was what Polk sent as warranty claim replacements for the Peerless. Hard to say which speaker is the better way to go, and without more info. about the crossovers and drivers, a tough decision. So, you have to buy them both lol.

    PS: I believe at some point the 7 went from an 8 Ohm nom. impedance rating (7B and earlier) to 6 Ohms (7C w/ SL2000), and then (maybe) 4 Ohms.

    It's really confusing with three early tweeters (Peerless, SL-1000 & SL-2000) being used on so many different models and even versions of the same model.

    @MLampen Go with the first one.
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  • Gardenstater
    Gardenstater Posts: 4,502
    edited December 2020
    4 Ohm nom. possible impedance confirmed for the 7C with SL2000 and MW6502. So make sure your amp is rated for it. From Audio 1986 Equipment Directory

    jgawryhmsnt4.png

    However, this Polk manual shows a 7C with SL2000 and unknown MW driver, that has a 6 Ohm nom. impedance. It's possible that, nominal impedances not being an exact science, they wavered on what to say it was, 4 or 6. Crazy stuff eh?

    z7gxv2ien4rp.png

    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
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  • Gardenstater
    Gardenstater Posts: 4,502
    edited December 2020
    And clearly there were early 7C's that were equipped with the SL1000 and fuses, as per Audio Oct 1984, and a 4 Ohm nom. impedance, so perhaps both of those you are considering are 4 Ohms.

    qymafu81owz5.png
    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
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  • MLampen
    MLampen Posts: 8
    Thank you guys for the feedback.

    Ya, this is pretty crazy with all the different components across the same models. Another example is my current 5's below.

    I think I'll try to take Pitdog's approach as I would want to upgrade the tweets and crossovers. The tweet upgrade will be much easier. Thanks for the wisdom there.

    What's more, per Gardenstaters info on the set in reference, I like that these would be 4ohm speakers. I have an SX-1250 that's rated at 4 ohms 200W per channel that'll be driving them. It's been overhauled and recapped over the past 2 years too.

    I love the way my monitor 5's sound so the 7's will be a nice upgrade especially with new crossovers, upgraded tweets and (maybe now) 4 ohms.

    This leads me further down the Polk rabbit hole however. I have Monitor 5's pictured below. SL2000 tweets, bevelled edges, and actually look just like the 4ohm, 7's set. I'm thinking, if the 5's were 4 ohms too, could I use both the 5's and 7's simultaneously?

    Lastly, one thing stood out on identifying the 5's based on the specs Gardenstater shared, is that the dimensions don't match any of the 3 spec sheets he shared.....

    Dimensions: 21-5/8" H x 10-1/2" W x 8-1/2" D
    (8-1/2" without grill cover, 9" with grill cover)

    3750xpflbb8v.jpg
    gxub5anz5c33.jpg
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  • F1nut
    F1nut Posts: 50,654
    Get the first pair.
    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

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  • Gardenstater
    Gardenstater Posts: 4,502
    edited December 2020
    It looks like the dimensions of your 5's are pretty darn close to those in the spec sheets, within 1/8" anyways.

    As far as running the 7's in parallel with the 5's, I would say it is a no go unless both speakers were 8 ohm nom. impedance which it looks like they are not. Even if they were both 6 ohm, that'd give you 3 Ohms and that would be pushing your receiver below it's rating. Heck, even 8 and 6 would give you 3.43 Ohms.
    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
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  • Lyttletowers
    Lyttletowers Posts: 2
    I’m new so what can I do to post pictures of early polks
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  • Lyttletowers
    Lyttletowers Posts: 2
    Mine have just one speaker below the tweeter. They were bought directly from Sandy Gross when he brought them in to a stereo shop on Reisterstown road and Green Spring Valley. I think it was 72.
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  • Gardenstater
    Gardenstater Posts: 4,502
    edited June 30
    Lyttletowers wrote: »
    Mine have just one speaker below the tweeter. They were bought directly from Sandy Gross when he brought them in to a stereo shop on Reisterstown road and Green Spring Valley. I think it was 72.

    I'm really looking forward to seeing those pictures !!! Hopefully this helps:

    0b5rfl7rm8qi.jpg

    sipljy5q2ryu.jpg

    It will be interesting to see if it is this one from a 1973 advertisement:

    zmjt7ao3drd6.jpg

    Post edited by Gardenstater on
    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
    · Share on FacebookShare on Twitter