Monitor 7s recap

PeteyWheaty
PeteyWheaty Posts: 4
in Vintage Speakers
g004xrz8483q.jpeg

I just picked up a pair from a Goodwill auction, and I'm excited to give these a refresh - both the crossovers and the cabinets. I believe these are 7Cs? Any recommendations on manufacturers?
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  • F1nut
    F1nut Posts: 51,674
    edited December 6
    Clarity CSA or Jantzen Superior Z caps. Vishay-Mills resistors.

    While you're in there, replace that little blue polyswitch with a 0.5 ohm Vishay-Mills resistor.

    You'll also want to upgrade the tweeters to the RD0194-1 available from Polk.
    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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  • xschop
    xschop Posts: 5,057
    Why not TL-mod them?
    Don't take experimental gene therapies from known eugenicists.
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  • Gardenstater
    Gardenstater Posts: 4,739
    edited 5:40AM
    Try an Audience Auricap XO 12 uf. Rated even higher than Jantzen Superior Z and it is $42.66 vs. $68.17. Sonicap is $57.27 and ClarityCap CSA is $26.68.

    You'd be the first one here to have tried the Audience afaik 😉 PS: except for maybe DarqueKnight (rip) 😥
    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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  • PeteyWheaty
    PeteyWheaty Posts: 4
    xschop wrote: »
    Why not TL-mod them?

    What is a TL mod? I see references on an SDA refurb thread, but not much detail for a noob.

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  • PeteyWheaty
    PeteyWheaty Posts: 4
    Before I pull the trigger, have I gotten it right?

    ngt22usqa2ft.png
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  • xschop
    xschop Posts: 5,057
    TL mod requires the RD-0198 tweeters and a pair of 5.8uf caps.

    I'll try to find a 7C-TL Mod thread. The search function is sketchy here..

    Welcome aboard BTW

    Don't take experimental gene therapies from known eugenicists.
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  • Gardenstater
    Gardenstater Posts: 4,739
    edited 8:47AM
    yes 5.8 uF, not 4.0 uF. That 34uF could be a 33uF Clarity Cap CSA to save money if you wanted. 10W or 12W for the 2.0 Ohm tweeter resistors, not 5W which wouldn't be an upgrade over what is there, power wise. You have 2R2 in your cart which is wrong. That's 2.2 Ohms and you need 2.0 Ohms. You also need to get a Jantzen 0.27mH, 0.5 Ohm inductor so it isn't totally a simple mod.

    6imw1m90vpsr.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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  • xschop
    xschop Posts: 5,057
    I'd wager if he removed his factory tweeter inductors, they'd measure higher than .23mH. JAT
    Don't take experimental gene therapies from known eugenicists.
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  • DeRod
    DeRod Posts: 235
    Jantzen crosscaps 18uf+16uf=34uf and the Auricap 12uf would work very well I'm sure
    "Equality is a myth to protect the weak. Some of us are strong in the Force, others are not. Only a fool believes otherwise." - Sith Proverb.
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  • Gardenstater
    Gardenstater Posts: 4,739
    xschop wrote: »
    I'd wager if he removed his factory tweeter inductors, they'd measure higher than .23mH. JAT

    I think that's a possibility for sure, if OP has or wants to get the measurement equipment. I don't know what the DCR would be of the stock inductor. Needs to be 0.5 Ohms now.

    This would work. I don't know if you can get them elsewhere other than hificollective

    https://www.hificollective.co.uk/catalog/000-1640-027mh-jantzen-air-core-wire-coil.html
    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: 4,739
    See if you can order it. Jantzen might not have that as a stock size any more but they custom make them to order I believe.

    https://jantzen-audio.com/product-category/air-core-wire-coil/?min_inductance=0.26&max_inductance=0.28&min_dcr=0.48&max_dcr=0.52&min_wind_wire&max_wind_wire&min_awg&max_awg&min_inner_diameter&max_inner_diameter&min_outer_diameter&max_outer_diameter&min_height&max_height&index_value
    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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  • xschop
    xschop Posts: 5,057
    ^^^At 4 bucks a pop, that's a no-brainer. B) ^^^
    Don't take experimental gene therapies from known eugenicists.
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  • F1nut
    F1nut Posts: 51,674
    PeteyWheaty wrote: »
    Before I pull the trigger, have I gotten it right?

    ngt22usqa2ft.png

    Hell no, you don't want those and forget about the TL mod BS or advice from the speculators.
    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: 4,739
    edited 11:30AM
    @PeteyWheaty Here is WMG's (RIP) thread on this. I "think" he used a 12uF plus 22uF Clarity Cap CSA to make the 34uF, instead of using the 33uF. Also, being in the crossover business it sounds to me like he had an inductor left over from some other project that he was able to tune to get the proper value.

    @f1Nut maybe you could somehow LOL everything in WMG's thread. I think you missed a few.

    https://forum.polkaudio.com/discussion/192120/monitor-7-with-tl-upgrade#latest

    Capacitor ratings (one man's opinion but he SURE is experienced)

    https://www.humblehomemadehifi.com/Cap.html
    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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  • xschop
    xschop Posts: 5,057
    F1nut wrote: »
    PeteyWheaty wrote: »
    Before I pull the trigger, have I gotten it right?

    ngt22usqa2ft.png

    Hell no, you don't want those and forget about the TL mod BS or advice from the speculators.

    LMAO, WMG was a plethora of info on modding these vintage Polks.

    From experience, the only great sounding 7C's with RD-0194's had billet plates installed. Full-modded 7C's with 198's are the best of vintage Polk monitors.
    Don't take experimental gene therapies from known eugenicists.
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  • F1nut
    F1nut Posts: 51,674
    With respect to Dave (R.I.P.) that was not a Polk designed, tested or approved modification.
    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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  • xschop
    xschop Posts: 5,057
    F1nut wrote: »
    With respect to Dave (R.I.P.) that was not a Polk designed, tested or approved modification.

    With respect to DarkKnight, neither was the 1K/800VA Dreadnaught, but it is arguably the one of the best things to happen to vintage SDA mods.
    Don't take experimental gene therapies from known eugenicists.
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  • F1nut
    F1nut Posts: 51,674
    xschop wrote: »
    F1nut wrote: »
    With respect to Dave (R.I.P.) that was not a Polk designed, tested or approved modification.

    With respect to DarkKnight, neither was the 1K/800VA Dreadnaught, but it is arguably the one of the best things to happen to vintage SDA mods.

    It's well known that Matt Polk stated the AI-1 could easily be improved upon and in fact consulted with Ray about that. So yes, it was Polk approved.
    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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  • F1nut
    F1nut Posts: 51,674
    Capacitor ratings (one man's opinion but he SURE is experienced)

    https://www.humblehomemadehifi.com/Cap.html

    One has to read between Tony's lines and personal experience helps too.

    I quote Tony about the Superior Z.
    One of my personal allround favourites :-)

    I agree!

    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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  • xschop
    xschop Posts: 5,057
    Fair enough, my point was Polk didn't sign-off on alot of mods. They did sign-off on the plastic SL-2000's. Worst tweeter ever IMO.
    Don't take experimental gene therapies from known eugenicists.
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  • bcwsrt
    bcwsrt Posts: 2,363
    DeRod wrote: »
    Jantzen crosscaps 18uf+16uf=34uf and the Auricap 12uf would work very well I'm sure

    So, it’s not something you yourself have tried (you know, with pics and all …)?

    Brian

    One-owner Polk Audio RTA 15TL speakers refreshed w/ Sonicap, Vishay/Mills and Cardas components by "pitdogg2," "xschop" billet tweeter plates and BH5 | Stereo REL Acoustics T/5x subwoofers w/ Bassline Blue cables | Rogue Audio Cronus Magnum III integrated tube amp | Technics SL-1210G turntable w/ Ortofon 2M Black LVB 250 MM cart | Teac VRDS-701T CD transport | LampizatOr Baltic 4 tube DAC | Nordost & DH Labs cables/interconnects | APC H15 Power Conditioner | GIK Acoustics room treatments | Degritter RCM
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  • Gardenstater
    Gardenstater Posts: 4,739
    CAPS WARS !!!!!

    This is kind of ridiculous. I told the OP that nobody that I know in the forum except for DarqueKnight has used them but they ARE rated higher than Superior Z by TonyG fwiw. He gave it an 11 instead of 10.25. He specifically COMPARES them in his summary. I have no personal knowledge of it and I said as much, but neither do you. Oh and it is quite a bit cheaper and ON SALE.

    6j2jjyaj4t0d.jpg
    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
  • DeRod
    DeRod Posts: 235
    bcwsrt wrote: »
    DeRod wrote: »
    Jantzen crosscaps 18uf+16uf=34uf and the Auricap 12uf would work very well I'm sure

    So, it’s not something you yourself have tried (you know, with pics and all …)?

    wm9msmcpmfr4.jpeg

    Clowntown 🤡

    Yes and all 🤣🤣

    Don’t compare me to yourself. It’s just going to make you sad. 🤣🤣

    "Equality is a myth to protect the weak. Some of us are strong in the Force, others are not. Only a fool believes otherwise." - Sith Proverb.
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  • Gardenstater
    Gardenstater Posts: 4,739
    edited 1:18PM
    The culture around here has hit the skids.
    @DeRod WMG did a 22 and a 12. You did an 18 and a 16 and saved even more for a midwoofer shunt capacitor. Brilliant minds think alike 🤣 Still considered in the audio path but is it as important as a series capacitor? I really don't know to be honest. WMG has hinted he didn't think it was IIRC.
    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
  • xschop
    xschop Posts: 5,057
    Still waiting on F1's foam-frame mod review. o:)
    Don't take experimental gene therapies from known eugenicists.
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  • Gardenstater
    Gardenstater Posts: 4,739
    edited 3:10PM
    xschop wrote: »
    Fair enough, my point was Polk didn't sign-off on alot of mods. They did sign-off on the plastic SL-2000's. Worst tweeter ever IMO.

    Inquiring minds need to know. Who did the hand modified SL3000 mod sketches we have in our archives for the 5, 10, CRS+. Also, why is there not one for the 2B and the 7 even though the 2B has the same schematic as CRS+ and the 7C has the same schematic as the 5B? Why have so many people TL modded them and reported great results? So, all the hand sketched ones in the archives are not officially Polk sanctioned? Seems like those were just thoughtful workarounds for the people who had the pre Series 2 versions of the monitors and I guess there never was an official SDA 2B or CRS+ that shipped with the SL2500 or SL3000?. If so, of course there is no official schematic.

    PS: Mark Doro posted those non SDA schematics in the vintage section. I believe he was Online Polk Sales Representative?
    Post edited by Gardenstater at
    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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  • PeteyWheaty
    PeteyWheaty Posts: 4
    Wow. Quite the apple of discord I've rolled onto the table. Maybe I'll focus on refurbing the cabinets and stands, first! ;)

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  • VR3
    VR3 Posts: 29,385
    Those are Polk official modifications but the revisions were never officially released is my understanding

    The market was gravitating away from larger speakers
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
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  • F1nut
    F1nut Posts: 51,674
    edited 2:40PM
    From my post in 2010.
    I have seen a military sales brochure that listed the CRS+ as a 4.1TL, but it does not appear that any were actually sold as the production of SDA's ended at that time.
    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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  • pitdogg2
    pitdogg2 Posts: 26,926
    Auricap, there's one other consideration to ponder. There is a reason some have black and red leads
    Per Auricap
    If you check the Auricap documentation
    you will see what the manufacturer recommends:
    " LEADS

    In signal path applications the black lead is "in" and the red lead is "out."

    In power supplies the black lead should be connected to ground and the red lead to the + or – voltage.

    In loudspeaker crossovers the red lead should be connected toward the + terminal on the drive unit."
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