Polk RTA 11TL sounding awful

JRH13
JRH13 Posts: 7
in Vintage Speakers
19bl5j6ih7pu.jpg
Hello, I am resurrecting my old home stereo system and am having an issue with one of my Polk RTA 11TL's. I am running the pair off a Nakamichi Receiver 2 from 1992. One speaker sounds amazing and the other awful; flat and barely audible.
I switched the speaker wires to be sure it was cross-connected as well as switching the speakers to both the left and right sides of the receiver with the same result.
I inspected the speakers and they all seem and feel fine, moving slightly in and out to the touch, which led me to googling possible causes.
Could I have a bad resistor? I then started looking around for replacements and videos on how to do it but I wanted to check around with some folks in the know before trying it on my own.
Any advise? Thanks!rfojr8kfo40f.jpg
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  • Gardenstater
    Gardenstater Posts: 4,455
    I'm looking at this schematic:

    https://us.v-cdn.net/5021930/uploads/attachments/4/6/7/2/8/18708.pdf

    and I see that it shows 3 capacitors whereas it looks like you have 4? Is that a 12uf electrolytic in parallel with a 16uf mylar capacitor on your crossover?

    The schematic above only has a 12uf electrolytic, 16uf mylar, and 34uf electrolytic.
    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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  • bcwsrt
    bcwsrt Posts: 1,876
    Do you have sound out of both tweeters?

    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 | Sony CDP-508ESD CD player (as a 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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  • JRH13
    JRH13 Posts: 7
    Let me double-check.
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  • JRH13
    JRH13 Posts: 7
    Gardenstater wrote: »
    I'm looking at this schematic:

    https://us.v-cdn.net/5021930/uploads/attachments/4/6/7/2/8/18708.pdf

    and I see that it shows 3 capacitors whereas it looks like you have 4? Is that a 12uf electrolytic in parallel with a 16uf mylar capacitor on your crossover?

    The schematic above only has a 12uf electrolytic, 16uf mylar, and 34uf electrolytic.

    I have no idea. I just pulled it for the first time.
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  • pitdogg2
    pitdogg2 Posts: 25,412
    Either way that's all factory. I've seen some strange factory crossovers over the years.
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  • Gardenstater
    Gardenstater Posts: 4,455
    JRH13 wrote: »
    Gardenstater wrote: »
    I'm looking at this schematic:

    https://us.v-cdn.net/5021930/uploads/attachments/4/6/7/2/8/18708.pdf

    and I see that it shows 3 capacitors whereas it looks like you have 4? Is that a 12uf electrolytic in parallel with a 16uf mylar capacitor on your crossover?

    The schematic above only has a 12uf electrolytic, 16uf mylar, and 34uf electrolytic.

    I have no idea. I just pulled it for the first time.

    It is possible they ran out of 16uf mylar capacitors and substituted a 12uf electrolytic in parallel with a 4uf mylar. That would be cra.ptastic. if they did that! Check the yellow one to see what value is printed on it.
    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: 5,000
    Ohm out the tweeters to make sure they are not shorted/burnt.
    Don't take experimental gene therapies from known eugenicists.
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  • JRH13
    JRH13 Posts: 7
    bcwsrt wrote: »
    Do you have sound out of both tweeters?

    I am getting sound out of all speakers. It is all muted and falt and low in volume, if that makes sense. None sound any better than the rest, they are all equally bad.
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  • Gardenstater
    Gardenstater Posts: 4,455
    If you have a meter and know how to use it, would be a good idea to check how both speakers ohm out across the + and - terminals on the binding posts.
    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
  • F1nut
    F1nut Posts: 50,494
    JRH13 wrote: »
    bcwsrt wrote: »
    Do you have sound out of both tweeters?

    I am getting sound out of all speakers. It is all muted and falt and low in volume, if that makes sense. None sound any better than the rest, they are all equally bad.

    Are the red binding posts on the left or right looking at the cabinet from the rear?
    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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  • skrol
    skrol Posts: 3,372
    edited May 2023
    My RTA11TL crossovers were just like yours with 12uF electrolytic bypassed with a 4uF mylar. The engineer said it was intentional from the factory but recommended replacing when I asked about upgrades. At least yours are soldered. Mine had the leads just wrapped around the other. Must have knocked off early that day.

    When I upgraded my crossovers, I went with a 16uF film capacitor instead of the 2 paralleled.

    The RTA11TL responds very well to crossover upgrades and RD0-198 tweeter upgrade.
    Stan

    Main 2ch:
    Polk LSi15 (DB840 upgrade), Parasound: P/LD-1100, HCA-1000A; Denon: DVD-2910, DRM-800A; Benchmark DAC1, Monster HTS3600-MKII, Grado SR-225i; Technics SL-J2, Parasound PPH-100.

    HT:
    Marantz SR7010, Polk: RTA11TL (RDO198-1, XO and Damping Upgrades), S4, CS250, PSW110 , Marantz UD5005, Pioneer PL-530, Panasonic TC-P42S60

    Other stuff:
    Denon: DRA-835R, AVR-888, DCD-660, DRM-700A, DRR-780; Polk: S8, Monitor 5A, 5B, TSi100, RM7, PSW10 (DXi104 upgrade); Pioneer: CT-6R; Onkyo CP-1046F; Ortofon OM5E, Marantz: PM5004, CD5004, CDR-615; Parasound C/PT-600, HCA-800ii, Sony CDP-650ESD, Technics SA 5070, B&W DM601
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  • JRH13
    JRH13 Posts: 7
    F1nut wrote: »
    JRH13 wrote: »
    bcwsrt wrote: »
    Do you have sound out of both tweeters?

    I am getting sound out of all speakers. It is all muted and falt and low in volume, if that makes sense. None sound any better than the rest, they are all equally bad.

    Are the red binding posts on the left or right looking at the cabinet from the rear?

    The red is on the left, looking at it from the back.
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  • JRH13
    JRH13 Posts: 7
    skrol wrote: »
    My RTA11TL crossovers were just like yours with 12uF electrolytic bypassed with a 4uF mylar. The engineer said it was intentional from the factory but recommended replacing when I asked about upgrades. At least yours are soldered. Mine had the leads just wrapped around the other. Must have knocked off early that day.

    When I upgraded my crossovers, I went with a 16uF film capacitor instead of the 2 paralleled.

    The RTA11TL responds very well to crossover upgrades and RD0-198 tweeter upgrade.

    Thanks for your reply, that is encouraging to hear. Did you replace all three?
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  • bcwsrt
    bcwsrt Posts: 1,876
    The resistor you asked about earlier is only in the tweeter circuit, so you have more diagnosing to do if the sound is “off” on all three of the main drivers, equally.

    What you described sounded possibly like a blown tweeter to me, but if it is still producing audible high frequencies, muted and low volume as they may be, something else is going on. I’d want to narrow it down vs. just throwing parts at the crossover hoping to fix it.


    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 | Sony CDP-508ESD CD player (as a 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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  • F1nut
    F1nut Posts: 50,494
    JRH13 wrote: »
    F1nut wrote: »
    JRH13 wrote: »
    bcwsrt wrote: »
    Do you have sound out of both tweeters?

    I am getting sound out of all speakers. It is all muted and falt and low in volume, if that makes sense. None sound any better than the rest, they are all equally bad.

    Are the red binding posts on the left or right looking at the cabinet from the rear?

    The red is on the left, looking at it from the back.

    Good, supposed to be.
    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: 4,455
    edited May 2023
    You could have a bad binding post connection or a cold solder joint to the PCB. If you don't have a meter I'd pick up a cheap one at Harbor Freight or elsewhere and learn how to use it and check across + and - and also each of the drivers individually across their + and - terminals. Jot down all the readings and try to make some sense of things. You can find out what is the problem or at least what is not the problem.
    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
  • JRH13
    JRH13 Posts: 7
    I swapped out the tweeter from the other speaker and it sounds great, so I guess that was the problem. I am still curious about recapping, but I think I will just order a set of RD0-198's and enjoy it for a little while. Thanks to everyone who replied. If anyone has any suggestions about upgraded crossovers, please let me know.
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  • skrol
    skrol Posts: 3,372
    Yes, I replaced all the caps with Clarity Cap PX and the resistor with Mills (or Mundorf). There are other good caps out there like SoniCap. I did not change the inductors.
    Stan

    Main 2ch:
    Polk LSi15 (DB840 upgrade), Parasound: P/LD-1100, HCA-1000A; Denon: DVD-2910, DRM-800A; Benchmark DAC1, Monster HTS3600-MKII, Grado SR-225i; Technics SL-J2, Parasound PPH-100.

    HT:
    Marantz SR7010, Polk: RTA11TL (RDO198-1, XO and Damping Upgrades), S4, CS250, PSW110 , Marantz UD5005, Pioneer PL-530, Panasonic TC-P42S60

    Other stuff:
    Denon: DRA-835R, AVR-888, DCD-660, DRM-700A, DRR-780; Polk: S8, Monitor 5A, 5B, TSi100, RM7, PSW10 (DXi104 upgrade); Pioneer: CT-6R; Onkyo CP-1046F; Ortofon OM5E, Marantz: PM5004, CD5004, CDR-615; Parasound C/PT-600, HCA-800ii, Sony CDP-650ESD, Technics SA 5070, B&W DM601
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  • audioluvr
    audioluvr Posts: 5,578
    JRH13 wrote: »
    If anyone has any suggestions about upgraded crossovers, please let me know.

    Send them in to DHS Speaker Repair if you don't want to do the soldering yourself. Money well spent.
    Gustard X26 Pro DAC
    Belles 21A Pre modded with Mundorf Supreme caps
    B&K M200 Sonata monoblocks refreshed and upgraded
    Polk SDA 1C's modded / 1000Va Dreadnaught
    Wireworld Silver Eclipse IC's and speaker cables
    Harman Kardon T65C w/Grado Gold. (Don't laugh. It sounds great!)

    There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January. by Dr. Sardonicus
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  • bcwsrt
    bcwsrt Posts: 1,876
    Thanks for the follow-up on what you found.

    The crossover upgrade suggestions are numerous here. I had gracious and copious help from a forum member on my 15TLs and went with Sonicap and Vishay Mills. Could not be happier. You can’t turn the 11s into something they aren’t, but you can make them better than they ever were.

    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 | Sony CDP-508ESD CD player (as a transport) | LampizatOr Baltic 4 tube DAC | Nordost & DH Labs cables/interconnects | APC H15 Power Conditioner | GIK Acoustics room treatments | Degritter RCM
    · Share on FacebookShare on Twitter