I'm back in on Monitor 7's.....finally...or sort of....I think.

Ten or so years ago I got pulled into the vintage Polk sound after getting a free pair of 5jr+'s that I subsequently gave to my daughter. Those sweet little babies pulled me into a pair of 7B's that I eventually made stands for and recapped.

During that time I was going through a good amount of gear, buying, selling, repairing etc... But the 7B's rose to the top and I loved the way they sounded with a variety of associated gear. Particularly after the 'surgery'.

Things changed, we moved and stuff had to go. Since then I've thought about stuff I parted with; Infinity, Snell, EPI, AR, KEF, but eventually the ones I regretting selling off the most was the 7B's.

Recent events have gotten me bit by the bug again and damn if I didn't run into a pair of 7's locally listed. Paid too much? Maybe. But they are in very nice shape and play beautifully as is. Of course given my previous experience I am not going to be able to leave them alone and I am looking forward to getting these into reference condition.

So I believe I'm dealing with Monitor 7 Series II's. The lineage is a bit confusing as we all know Polk made changes willy-nilly but the date stamps on the tweeter and one of the caps are from 1987.

My 7B's had a flat front edge, badge on the wood, peerless tweeter and external fuse. These have a beveled front edge, badge on the grill, the SL2000 tweeter and no external fuse and no poly switch either.

As I've read much on the original 7 models I haven't focused much on the series II. Is there a prevailing opinion on if the II's are as update worthy as the earlier models?

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Comments

  • aprazer402aprazer402 Posts: 1,173
    edited September 28
    Definitely not Monitor 7 "Series II" They were not out until 1990 +/- 6 months. Crossover dated 1987. Series II had the SL2500 tweeter, the one shown has the SL-2000. No fuse on rear above binding posts, I'd say 7C's. 7's and & 7B's had fuse(s) and most had Peerless tweeters.
  • delkaldelkal Posts: 345
    I guess I always thought for most of the original Monitor line..........

    The A's had the fuse and Peerless tweeters
    The B's had the polyswitch and the Sl-2000 tweeters (like yours has)
    And the Series 2's had the newer SL-2500 tweeters.

    This is the way the original 5's and 10's were set up so I don't see why this would not apply to the 7's also ( but I am sure we will find out soon though).
  • JonesyJonesy Posts: 189
    Well isn't Polk archeology fun!

    There seems to be as many opinions as there are posts on as many different forums. One post states series II doesn't start until 1990 and has the sl2500. The 'official' SDA series chart doesn't show anything produced in the 7 line after 1990 except the II's yet mine have the sl2000's dated 1987, along with the 12u cap dated 1987.

    Possible these are 7 series II's that had the tweeters replaced with sl2000's (why? stranger things have been done I guess)? The SDA lineage timeline shows 7C's only at 1979. This would make a difference when it comes time to replace the tweets. 194's to match the 7C's or 198's to match the series II's.

    Thanks Polk. Love ya Polk! Really. It's kinda fun (sorta).

    Perhaps the only definitive answer is to call Polk to order the tweets, give them the serial # and put it on them.

    Regardless, I think were down to either tweeter hacked II's or very late production C's that aren't reflected in the SDA chart.
  • JonesyJonesy Posts: 189
    Well I don't see an edit function so I just wanted to be clear. My old eyes failed to see the poly switch until I looked at the pics. It's there.
  • pitdogg2pitdogg2 Posts: 11,467
    It would be easy to check. Take tweeter out are both quick connects the same size or two sizes?
    Both same RD-0194
    Different sized RD-0198

  • motorhead43026motorhead43026 Posts: 2,909
    edited September 28
    My 10's are series 2, thought my 7's were but they are 7C's.

    Anyway, these 7's no matter the series are a great speaker.
    2 channel: Anthem 225 Integrated amp; Parasound Ztuner; TechnicsTT SL1350; Vincent PHO-8 phono pre; Marantz CD6005 spinner; Polk Signature S60's;Cables: Wireworld Eclipse IC; Audioquest Big Sur IC; LAT International speaker cables; PS Audio AC-3 power cords, all into a PS Audio Dectet Power center.

    All TV's sound enhanced by Polk Magnfi Mini's.

    Other; SDA2BTL's, M10 series II, M7C's, Hafler XL600 amp, RB-980BX, Parasound HCA-1500 amp , P5 preamp, all in storage. All speakers have had crossover rebuilds, resulting in a small fortune invested in Sonicaps, and tweeter upgrades.

    Political memes posted as fact and accepted as fact, are sign language of the ignorant, for the ignorant

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  • JonesyJonesy Posts: 189
    pitdogg2 wrote: »
    It would be easy to check. Take tweeter out are both quick connects the same size or two sizes?
    Both same RD-0194
    Different sized RD-0198

    Both are sl2000
  • pitdogg2pitdogg2 Posts: 11,467
    Jonesy wrote: »
    pitdogg2 wrote: »
    It would be easy to check. Take tweeter out are both quick connects the same size or two sizes?
    Both same RD-0194
    Different sized RD-0198

    Both are sl2000

    Right I see that. If they originally had the SL2500 it would take two different sized quick connects. You made the comment that they may of switched tweeters. Therefore the quick connects would give it away and also tell you which replacement tweeter to get.
  • aprazer402aprazer402 Posts: 1,173
    edited September 28
    I found a few threads regarding Monitor 7's. There are probably several hundred of them. These might be helpful, if not, maybe somewhat interesting.

    http://forum.polkaudio.com/discussion/52499/monitor-7a-b-c-question

    http://forum.polkaudio.com/discussion/137297/polk-monitor-7as-vs-7cs-comparison

    http://forum.polkaudio.com/discussion/51647/monitor-7s-and-7as

    http://forum.polkaudio.com/discussion/comment/2381456#Comment_2381456

    http://forum.polkaudio.com/discussion/comment/2397566#Comment_2397566

    http://forum.polkaudio.com/discussion/comment/2385411#Comment_2385411

    http://forum.polkaudio.com/discussion/comment/2299582#Comment_2299582

    http://forum.polkaudio.com/discussion/comment/2038818#Comment_2038818

    http://forum.polkaudio.com/discussion/comment/319187#Comment_319187

    In the last thread listed note the photo GrahamT attached to his post, his post is the fourth from the bottom, it shows his early 1985 7C's with a fuse and a SL1000 tweeter. Some 7C's lacked the fuse, they had a polyswitch, and used the SL-2000 tweeter.

    The Monitor 7's probably have most confusing time-line to follow. The individual models overlapped years and different components were used apparently interchangeably. Monitor 5's & 4's can also be difficult to follow. Labeling did not always include a letter suffix on the rear label after the model number.

    My 1986 Monitor 10B's are only shown as Monitor 10 on the label on the speaker back, but the cardboard box they came in had a large "B" stamped on the box.












  • JonesyJonesy Posts: 189
    pitdogg2 wrote: »
    Jonesy wrote: »
    pitdogg2 wrote: »
    It would be easy to check. Take tweeter out are both quick connects the same size or two sizes?
    Both same RD-0194
    Different sized RD-0198

    Both are sl2000
    If they originally had the SL2500 it would take two different sized quick connects.

    Copy that. Thank you sir. I finally get it. So these must be original sl2000's. Which means, 7C's? I guess?
  • F1nutF1nut Posts: 40,627
    Those are 7C's, period.

    Best thing you can do is upgrade to RD0194 tweeters, upgrade the caps and resistors and get some real speaker cables.
    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."


  • JonesyJonesy Posts: 189
    (not meant to be sarcastic at all)

    Ahhhhh......I feel much better.

    Thank you Nut. The definitive authority has chimed in at the right time.

    Can we call them 1987 7C's?

    Now that I have a vintage, a model and am able to plan an update path I will post progress as it occurs.

    BTW, don't judge me on the speaker cable. Totally temporary slop that was laying around in order to test things out. I run 12 ga on all my permanent systems. But thanks for the concern.
  • ThomasDThomasD Posts: 158
    Recently upgraded my 1985 7c's to TL status (via an outstanding x/o upgrade by @westmassguy) and performed the all the other basic improvements, i.e., RD-0198's, Hurricane nuts, Dyna-mat (or equivalent), BH 5, Armacell etc. Can not emphasize enough how much improvement in SQ happened. Can only describe it as 'Liquid' music now. Substantially improved smoothness & definition from the SL-2000's, more than enough low end bass (for me anyway). I don't even use my sub anymore with the 7's, prefer the crispness of the MW's & PR. All my digital & vinyl music has become a new experience to listen to now with so many more musical nuances that just weren't there before the upgrades. Makes my unmolested SDA2a's pale in comparison now. They are next on the upgrade list. As many on this forum & others have previously stated, the 7's were truly one of Polks 'Gems".
    Carver M1.0t, M200t, TX2, C2, Marantz 2230, Rega Brio, Marantz Imperial 7's, Klipsch Quartets, KG4's, KG1's, 'The Sixes', R-12SW, Polk SDA 2a's, Polk Monitor 7cTL's, Pro-ject Acryl TT, Cambridge 851N, 351C, Panamax 5300PM
  • JonesyJonesy Posts: 189
    Well that's an impressive testimonial for the TL mod. I've done a little initial reading on it, but now may have to investigate further. I remember the significant improvement after recapping my old 7B's. Considering those had the peerless perhaps the TL mod on these 7C's would put them closer to the old B's in performance?
  • DSkipDSkip Posts: 15,131
    edited September 30
    To piggy back on nuts post, if you can only describe your better cable as 12 gauge then you owe it to yourself to give some boutique types a try. I recommend PNF on a budget but they're only available used and never sold anymore. I horded a few pair of the interconnects and speaker cable until I became a dealer. It was then that I finally found a cable in the Wireworld Equinox to beat them at all turns. Even then, it was tough to stomach selling the PNF since they only go for around $100 per pair and outperform that number considerably.
    audiothesis.com/

    Speakers: Harbeth: 30.2, SHL5+; Usher: Be-10, T-515; Rosso Fiorentino: Elba, Pienza, Certaldo, Fiesole, Volterra; Polk: T50, Signature S15, RTA 15tl, RTi12; Sonner Audio Allegro Unum, Legato Unum, Legato Semis, Legato Duo; Emerald Physics CS-2.8; Klipsch KLF-20
    Preamps: Shuguang S200MK, Dayens Ampino, Parasound P5
    Amps: Shuguang S845MK, Dayens Ampino Monoblocks, Parasound A23
    Integrateds: Triode Corporation TRV-88SER, MastersounD: BoX, Dueventi, Compact 845, Evolution 845; North Star Design Blue Diamond
    Sources: AURALiC Aries, Denon HEOS Link, North Star Design: Magnifico, Supremo, Incanto, Intenso, Venti
    Cabling: Wireworld
    TV: Sony XBR-75X940C
  • rooftop59rooftop59 Posts: 4,753
    And if you haven’t already, there’s a little karma in the flea market. A chance to experiment will a little better cable for little investment... if ur lucky!
    HT Rig:
    Denon AVR-X4200w; Peachtree Audio Nova Integrated; Bryson BPD-1; Mains: Dynaudio Emit 10 + MartinLogan Dynamo (original) sub; Center - Polk cs400i; Heights, Center Surround - Klipsch KHC - 6 In-Ceiling; Surrounds - Monoprice in-ceiling; Sub - SVS PB10-ISD; LG UP870 4K BDP

    Master Bedroom
    Marantz SR-5007; Peachtree Audio NovaPre; Audiosource Amp Two, PSB Imagine B, Boston VR-10 center, NHT Super One CI surrounds, ACI Titan subwoofer, Squeezebox Touch
  • JonesyJonesy Posts: 189
    I appreciate the suggestions on cables and will play around with that aspect.

    Regarding the XO I'm starting to build a parts list but am not quite sure of what exactly I need as it's been a while since I did the old B's and there seems to be some difference between models, and even within models, as far as the XO design goes.

    It appears the 34u and 12u caps are the same, just a bit concerned on the resistor(s). I had 2 Mills on the build for the B's; 2.5 & 4.5 ohms at 12w but the lone resistor on these C's are labeled 2 ohm at 5w. Would the 2.5 @ 12w work for the resistor, and was the 4.5 ohm a replacement for the polyswitch?

    Man it sucks getting old.


  • pitdogg2pitdogg2 Posts: 11,467
    .5 ohm for the polyswitch 10 or 12 watt will work.
    While that 2.5 may work I'm not comfortable saying sure go ahead. Then again it may just quite the tweeter down a bit and be no problem.
  • ThomasDThomasD Posts: 158
    I might be mistaken but Thoight that @westmassguy had a thread on a pair of 7c’s he did with a complete material list. Can’t find it right at this moment but can attest to his wealth of information regarding x/o questions on the 7’s and others. Was hoping he might notice this thread and chime in.
    Carver M1.0t, M200t, TX2, C2, Marantz 2230, Rega Brio, Marantz Imperial 7's, Klipsch Quartets, KG4's, KG1's, 'The Sixes', R-12SW, Polk SDA 2a's, Polk Monitor 7cTL's, Pro-ject Acryl TT, Cambridge 851N, 351C, Panamax 5300PM
  • JonesyJonesy Posts: 189
    DSkip wrote: »
    To piggy back on nuts post, if you can only describe your better cable as 12 gauge then you owe it to yourself to give some boutique types a try.

    Just FYI, this is the cable that will be running this little rig. Nothing fancy. Soundking 12 ga and Vampire spades. A friend and I went in together and made a pile of these things a while ago. Basic homebrew cable, but quite competent.

    I drool over some boutique cables on occasion, but without a boutique budget this is the best I can do. Still appreciate the suggestion and will keep an eye out for some PNF's.

    jluvtpz0fxd0.jpg
  • tonyp063tonyp063 Posts: 484
    ThomasD wrote: »
    I might be mistaken but Thoight that @westmassguy had a thread on a pair of 7c’s he did with a complete material list. Can’t find it right at this moment but can attest to his wealth of information regarding x/o questions on the 7’s and others. Was hoping he might notice this thread and chime in.

    You aren't mistaken.
    Here's his thread with pics
    http://forum.polkaudio.com/discussion/175042/monitor-7-crossovers#latest
  • JonesyJonesy Posts: 189
    Brief thread but very helpful Tony, thanks.

    But it leaves me with a bit of concern. I already placed my order with PE for the Mills resistors. A 0.5 for the poly and straight 2ohm for the tweeter, which is what's in there now. I see westmassguy used 2.5's on that XO. Just concerned I got the wrong value.
  • F1nutF1nut Posts: 40,627
    You're fine, Dave used the 2.5 ohm instead of a 2.0 and .5 ohm.
    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."


  • JonesyJonesy Posts: 189
    Thanks nut.

    So I pulled these out of the initial testing rig and put them in what will be their final resting position with some gear they will have to live with for a little while.

    I was really reminded of what I loved about the B's that I cut loose. Nice presence and well balanced everywhere. Yet I know these can do more. Puts even more anticipation on getting the mods done, but I am now also eager to put the right gear behind it.

    The Nakamichi SR-2A receiver sounds very nice, and I think the Polks show how good of a receiver it is, but I know these drivers are begging to be grabbed ahold of and controlled. Since I really enjoyed the Yamaha juice that the old B's had I think I'm going to get the M-4 I have sitting dormant right now refurbished and track down a C-4 to go with it.

    Keep in mind these are just sitting on temporary paving blocks just to get them off the floor. Custom stands are in the planning stage.

    u7h1cg2i5f85.jpg
    00rhjicvm61i.jpg
  • la2vegasla2vegas Posts: 2,976
    edited October 7
    Jonesy wrote: »
    Thanks nut.

    So I pulled these out of the initial testing rig and put them in what will be their final resting position with some gear they will have to live with for a little while.

    I was really reminded of what I loved about the B's that I cut loose. Nice presence and well balanced everywhere. Yet I know these can do more. Puts even more anticipation on getting the mods done, but I am now also eager to put the right gear behind it.

    The Nakamichi SR-2A receiver sounds very nice, and I think the Polks show how good of a receiver it is, but I know these drivers are begging to be grabbed ahold of and controlled. Since I really enjoyed the Yamaha juice that the old B's had I think I'm going to get the M-4 I have sitting dormant right now refurbished and track down a C-4 to go with it.

    Keep in mind these are just sitting on temporary paving blocks just to get them off the floor. Custom stands are in the planning stage.

    u7h1cg2i5f85.jpg
    00rhjicvm61i.jpg

    You might want to place a floor mat or something on that left speaker cable, otherwise someone might drag em away.

    Did you catch that? He called him nut. :D
    2.3TL, 3.1TL, SDA 2B, SDA II, 7B, 7C, 7 series 2, 10B, 5JR+, 5JR, 5A, 4.5, 4, RTA 11TL, RTA 8TL, RTA 8T, LSI9, LSI7 EBONY, LSI7 CHERRY, LSIC, RTI A7, RTI A3, CSI A4, CSI A6, F/XI A4, RTI4. That's all for now.
  • mlistens03mlistens03 Posts: 2,327
    Yes. I accidentally pulled over my Mission speakers on em doing that. My dad’s Boston speaker’s were sitting on top, and they fell and broke, as I mentioned in PSOVLSK’s FS thread.
    Micah

    Main system: Technics SL3200, Shure M97xE, Lafayette LR1100 for tuner, Hagerman Audio Labs Bugle 2 phono stage, NAD C352 integrated, Boston Acoustics VR 2, Boston PV500, generic ICs, and BJC Belden speaker cables.

    Desktop: Dell Precision 690 running iTunes, Yamaha RX-v665, Monitor Audio R90s, Velodyne VA-907, generic ICs and speaker cables.
    I've always thought the goal of high-end audio was not to have your neighbors bang on the wall and say, 'Turn that darn music down' but to have your neighbors bang on the wall and say, 'Tell your friends to go home and you can practice later this week'.
  • JonesyJonesy Posts: 189
    So I'm starting to gather parts for the mods and it occurs to me that the electronics behind them need attention.

    I recall the 7B's responded very well to quality improvements of associated gear; receiver to separates then higher current current amps. Remembering that I have a Yamaha M-4 sitting in a box doing nothing I find a NAD 1020 preamp locally and swap out the Nakamichi SR-2A receiver that was pushing the C's.

    While that Nelson Pass designed Stasis circuit receiver was very competent it just wasn't enough juice. Just like the old B's did, these C's have really opened up with the M-4/1020 combo. Bigger soundstage, better imaging and just overall better presence.

    I'll be itching to get these mods (and stands) done!
  • westmassguywestmassguy Posts: 6,169
    Sorry I missed this. As @F1nut pointed out, the polyswitch, and single resistor are in series, so a single 2.5 ohm was used to replace them both
    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
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    Interconnect: Furez 10/2 with SpeakONs
    ICs: Custom Furez by Douglas Connections
    Den:
    Bose 901 Series II Continentals Restored, Re-Built Equalizer with Elna Silmic IIs, Sonicaps, and Silver Mica Caps
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    "And keep her under 70, would you, huh? Betty likes a slow ride"
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