Monitor 5 Jr+ upgrades?

ChrisD06
ChrisD06 Posts: 929
in Speakers
c35k0969o56f.jpeg
o9pqt5b6w1hy.jpeg

Never seen M5JR+ that are all black with a silver coil tweeter, but I had the chance to get them for pretty cheap so I bought them anyways.

What upgrades should I do? My current list is the following:

1. 4x4 BH5 behind woofer
2. RD tweeter
3. Dynamat woofer and PR basket
4. Rebuild crossover

Anything else for older vintage Polks or for this specific model, or do I have it all covered?
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Comments

  • Gardenstater
    Gardenstater Posts: 4,458
    Are the cabinet joints sound, especially at the bottom where it appears there is a gap in the miters? Baffle looks abnormally inset.
    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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  • ChrisD06
    ChrisD06 Posts: 929
    @Gardenstater
    Picking them up Monday. I'll check. If they're not sound should I bother picking them up and trying to fix the cabinet or should I pass? I've not seen vintage Polks for sale for over a year locally so this is a first.

    There is a pair of RTA 11T for $425 but I think that's too high.
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  • Gardenstater
    Gardenstater Posts: 4,458
    edited July 2023
    ChrisD06 wrote: »
    @Gardenstater
    Picking them up Monday. I'll check. If they're not sound should I bother picking them up and trying to fix the cabinet or should I pass? I've not seen vintage Polks for sale for over a year locally so this is a first.

    There is a pair of RTA 11T for $425 but I think that's too high.

    Totally fixable. Clamps, Titebond Glue, Blue painter's tape and a desire to do it. Could even run a fillet of glue around the inside, preferably something strong like JB Weld, or at least that's what I would use.
    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: 4,458
    edited July 2023
    Looks to me like the vinyl may have been painted. Perhaps they tried to repair the enclosure and messed up the vinyl and decided to paint. Can't tell for sure.

    PS: You probably have a pretty good idea of what I'd say regarding mods ( 🤣 ) but I'll just say whatever you do, I recommend doing one at a time. More fun that way and scientific regarding conclusions made.
    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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  • F1nut
    F1nut Posts: 50,495
    Cabinets are coming apart and there are strange marks on the surrounds. Hard pass.
    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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  • ChrisD06
    ChrisD06 Posts: 929
    @F1nut I'm gonna check them out more in depth on Monday. He has some RT35s I'm absolutely getting (mint condition).

    If it's just the bottom corners which are coming apart then I'll fix them IF they still have seal which I'll test with the radiator method.

    Here's something which will make you all laugh. Some guy had RT15s up for sale. Here's a photo he sent.

    7l33oalg9o9u.jpeg

    He said they work perfectly and sound great I was like LMFAO THE TWEETER IS GONE DUDE.
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  • xschop
    xschop Posts: 5,000
    I'D hold out for some 5A's or 5B's.

    Best 5Jr+ build I've seen here....

    https://forum.polkaudio.com/discussion/197449/original-owner-of-monitor-5jr-plus/p6
    Don't take experimental gene therapies from known eugenicists.
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  • ChrisD06
    ChrisD06 Posts: 929
    If they're not in good enough condition I'll just get the RT35 and hold out. I'll keep the 5A/B in mind.
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  • ChrisD06
    ChrisD06 Posts: 929
    Okay I got the M5JR and the RT35 both.

    The RT35 are in amazing condition so that was a no brainer.

    The Monitor 5 Jr are not painted black, but in fact, factory. Either that or it was done by a true professional. The woofers moved just fine and showed no signs of damage or magnet shift so I will immediately be buying JB weld to hold them in place. When pushing on the PR, the woofer pops up and returns to half way within a second, and then holds for a while and will return when I release the PR, so I assume the seal is good.

    This means the cabinet damage is most likely cosmetic so @F1nut you might be pleased to hear I'm not a total moron lol. Also the surrounds don't have marks, it's purely just the camera angle.

    The M5 are going to be a very fun project. First step is gluing the woofer magnets, then getting some epoxy and wood filler to fix the separation.

    Can't wait!
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  • F1nut
    F1nut Posts: 50,495
    Marks...
    xwgg3lv3ad2j.jpg
    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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  • ChrisD06
    ChrisD06 Posts: 929
    @F1nut I literally have them in person. From the photos it looks like they were hastily wiped down with a damp cloth or something. Look at the tweeter plate. The surrounds are in flawless condition.

    otj0sp4e9g48.jpg
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  • skrol
    skrol Posts: 3,372
    I could have sworn they were scraped based on the first photos too. Glad they look normal in recent photo.
    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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  • F1nut
    F1nut Posts: 50,495
    Looked scraped to me too. Glad that's not the case.
    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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  • ChrisD06
    ChrisD06 Posts: 929
    Glued my first magnets today!

    s09cp62n2pil.jpgi283fphz0vha.jpg

    First one was an absolute mess, second one wasn't too bad.

    I used Gorilla 2-part Epoxy. Going to let them cure for an hour and then once it's hardened enough I'll put it back in the M5JR+ and leave it to cure for the full 24-hours.

    Yeah I went overboard, but I'm never selling these speakers, so I think the peace of mind knowing the magnets will never shift is nice.

    @xschop rate my work please 🙏
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  • F1nut
    F1nut Posts: 50,495
    Use JB Weld, not 5 minute epoxy.
    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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  • ChrisD06
    ChrisD06 Posts: 929
    @F1nut I read through a forum from 2021 where you recommended to NOT use JB Weld, and I believe another forum where someone said to be careful with it because it's magnetic and can seep to the coil?

    Either way I've used this stuff before and it's beyond strong, like we're talking I could glue something together and it would require being thrown off the eiffel tower to consider breaking apart.

    If it holds then it holds.
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  • pitdogg2
    pitdogg2 Posts: 25,412
    edited July 2023
    ChrisD06 Posts: 176
    1:21PM
    @F1nut I read through a forum from 2021 where you recommended to NOT use JB Weld, and I believe another forum where someone said to be careful with it because it's magnetic and can seep to the coil?

    We did use loctite heavy duty powergrab for awhile. In the end it was NOT a good adhesive for metal. There is absolutely no way for JB weld to get into the voice coil. It's far too thick to wick between two pieces of metal that are glued together. I experimented with something like the gorilla you used on an old driver, it wasn't long lasting. After two years it turned yellow and I could peel it off the driver. The JB weld I used now almost 15 yrs ago is still very much glued and still going strong.
    We have tried several adhesives over the years and each time we seen to gravitate back to the tried and true JB weld two part adhesive.
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  • ChrisD06
    ChrisD06 Posts: 929
    @pitdogg2 Gotcha. Okay, I'll use the Gorilla for a year or so and once it's peelable I'll replace it with JB Weld. There wasn't even any JB Weld at my local hardware store so I needed something anyways to last a 4 hour road trip because I'll be damned if those magnets shift before I get to demo these properly.
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  • bcwsrt
    bcwsrt Posts: 1,876
    It’s super fun, isn’t it?!

    I saw a few conflicting posts on J-B Weld before I did mine, also. But, the stuff is so f*****g thick and sets up so fast, I ignored those and went with the majority.

    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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  • ChrisD06
    ChrisD06 Posts: 929
    Yeah I've used JB Weld before as well actually, to fix an engine block, and that stuff is stronger than I could have ever imagined.

    It was cool to see the inside of the speakers. The dacron is all behind the tweeter, I don't know if its supposed to be or not so I'll have to go through later and tear it back apart.
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  • pitdogg2
    pitdogg2 Posts: 25,412
    edited July 2023
    ChrisD06 wrote: »
    @pitdogg2 Gotcha. Okay, I'll use the Gorilla for a year or so and once it's peelable I'll replace it with JB Weld. There wasn't even any JB Weld at my local hardware store so I needed something anyways to last a 4 hour road trip because I'll be damned if those magnets shift before I get to demo these properly.

    Lay them on their backs and short the voice coils with a short piece of copper or speaker cable on both speakers. it will keep the drivers from flopping back and forth as much. A couple of thick towels help to cushion the ride as well.
    Shorting in case you're unsure is just running wire through both binding posts R & L on both. I just use a short U piece of 12 ga ground with from romax and tighten the binding post.
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  • ChrisD06
    ChrisD06 Posts: 929
    Can I ask why I should short them? Is it to use the magnetic field generated from the driver moving to hold the cones in place?

    Also I intended on this to begin with. RT35 will be stood up, M5JR+ will be on their backs.

    I CAN NOT WAIT TO BLAST THESE GUYS!! First ever vintage Polks and they've opened a new world of Polk collecting for me!
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  • aprazer402
    aprazer402 Posts: 3,145
    Have we actually seen failures of Loctite Powergrab used on the MW magnets?
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  • F1nut
    F1nut Posts: 50,495
    edited July 2023
    ChrisD06 wrote: »
    @F1nut I read through a forum from 2021 where you recommended to NOT use JB Weld, and I believe another forum where someone said to be careful with it because it's magnetic and can seep to the coil?

    Either way I've used this stuff before and it's beyond strong, like we're talking I could glue something together and it would require being thrown off the eiffel tower to consider breaking apart.

    If it holds then it holds.

    Changed my mind after figuring out that Loctite wasn't all it was cracked up to be.

    5 minute epoxy has its purposes, gluing the driver magnets isn't one of them. If one is hell bent on using an epoxy reach out to 3M as they make a multitude of them with very specific applications. Their epoxy products are top notch. Epoxy does much better when it's used between surfaces rather than a fillet bead as with the driver magnets. I've used their products on numerous items, incredible stuff.

    The 3M epoxy products are generally not too expensive, but the application gun is a bit steep for what it is.

    Another epoxy I have years of experience with is the West Systems epoxy. You use it with fillers, each with a specific purpose. One is for fillets, which is what we're doing with the magnets. The epoxy isn't cheap, but not crazy either. It's pretty much the standard for marine applications. I never had it fail in decades of use on boats.

    There is no way in hell that JB Weld can get into the VC. Never going to happen.
    Post edited by F1nut on
    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: 50,495
    edited July 2023
    aprazer402 wrote: »
    Have we actually seen failures of Loctite Powergrab used on the MW magnets?

    I recall someone either here or online performed stress tests with different adhesives. The Loctite didn't fair well.
    Post edited by F1nut on
    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: 5,000
    ChrisD06 wrote: »
    Glued my first magnets today!

    s09cp62n2pil.jpgi283fphz0vha.jpg

    First one was an absolute mess, second one wasn't too bad.

    I used Gorilla 2-part Epoxy. Going to let them cure for an hour and then once it's hardened enough I'll put it back in the M5JR+ and leave it to cure for the full 24-hours.

    Yeah I went overboard, but I'm never selling these speakers, so I think the peace of mind knowing the magnets will never shift is nice.

    @xschop rate my work please 🙏

    Most excellent. Any extra dribble is just extra anti-resonance 😎
    Don't take experimental gene therapies from known eugenicists.
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  • pitdogg2
    pitdogg2 Posts: 25,412
    ChrisD06 Posts: 179
    4:23PM
    Can I ask why I should short them? Is it to use the magnetic field generated from the driver moving to hold the cones in place?

    Answered your own question.
    Yes as I said, to keep the drivers from excessive movement.
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  • ChrisD06
    ChrisD06 Posts: 929
    @pitdogg2 Great! I'll short em for the road trip. I had no idea this was a thing but it makes sense. Will keep it in mind for future use!

    @xschop I thought of it that way too, until it dripped on the cone off my finger, but I was able to wipe that up completely.

    @F1nut I'll use JB weld for my future magnets. Will probably end up redoing the job on these guys after some time has passed for the Gorilla to be peelable.

    Now here's a question for everyone, are the MW7011 and such (the midwoofers used on the RT35, RT800, CS1000p, and hell, even the RT600i, CS400i, RTi70, just that general timeframe) prone to shifting? I'm worried about, well, every speaker I just listed there (I own them all, baby!) getting magnet shift. When did the magnets STOP shifting? Do I glue to be safe, has it been observed? I'm being super paranoid now.
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  • polkguy1994
    polkguy1994 Posts: 54
    Your solution to refurbishing those 5jr. $100.00, no fuse. Minnesota, MN.

    Polk Audio Monitor 5jr+


    https://www.facebook.com/marketplace/item/2203279433197579/?ref=category_feed&referral_code=null&referral_story_type=post&tracking=browse_serp:8a67b7c2-6ca0-4d76-9885-6fdf53510125
    I am looking for SRT Rears, seeking any information on the SRT history details to learn about this product!jjdas75rryoz.jpegw0n3asrf6chn.jpeg
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  • polkguy1994
    polkguy1994 Posts: 54
    https://scontent-ord5-2.xx.fbcdn.net/v/t45.5328-4/340448207_6218744761554961_3546982718531611437_n.jpg?stp=dst-jpg_s960x960&_nc_cat=104&ccb=1-7&_nc_sid=1a0e84&_nc_ohc=DncKF77mvl0AX9DM2Xs&_nc_ht=scontent-ord5-2.xx&oh=00_AfCwLc-ZZgyJL0zYGiZCZ-ETf7uU91jkgCCxn1mCK8aeIg&oe=64BF1707v25cewa2a6pk.jpeg
    I am looking for SRT Rears, seeking any information on the SRT history details to learn about this product!jjdas75rryoz.jpegw0n3asrf6chn.jpeg
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