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Can my speaker be repaired?

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  • Can my speaker be repaired?

    To make a long story short, around 1966, I had planned to build my own high powered solid state guitar amp. That project never worked out, and I was left with 4 100 watt "life time guaranteed" Jensen musical instrument speakers. Fast forward about 40 years and I bought a Crate "Power Block" amp, and build two 2x12 speaker cabs for the amp. I think I used the setup less than 10 times. Forward several more years... Yesterday I used the speakers to test out a stereo amp I picked up at a surplus store, and I noticed that one of the cabs was lower in volume than the other. I tracked it down to one of the speakers, not being dead, but being considerably lower in volume than the others. Can that sort of speaker problem be repaired? The Jensen company today, isn't the same Jensen company of the 60's, so I'm sure the life time guarantee isn't going to help.
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  • #2
    Yes, but I would also suggest that you find a pro audio recone shop and have them test all ofthe speakers to be sure there's nothing else wrong and that you have correctly diagnosed the problem. Where are you located?
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    Former product development engineer: Genz Benz, a KMC Music/Fender Musical Instruments Company, continuing factory level product support and service for Genz Benz

    Currently product development engineer: Mesa Boogie

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    • #3
      At what time in history did they start using that foam surround that would crap out after a couple decades? For starters assuming the wiring is good and there's no loose wires, remove a speaker and inspect the outer perimeter of the speaker cone. Is the foam at that interface decomposed? It can be repaired, and I'd bet a dollar that if that's the problem, then all four will need the same treatment. I've had speakers fixed this way at a pro's shop, and I've done it myself. One pro did a great job, another did a ****************ty job, and I did a job as good as the pro's. Repairing it professionally probably won't be financially worth it. Since you appear to be a DIY guy and the foam is the culprit, I'd recommend searching out the proper foam replacement on eBay and glue them on yourself. The first one will be interesting, the other three will then be easy.

      You must have a big garage to keep that kind of stuff around for so long. And you know, Lemmy used a busted cone on one of his speakers back in the day, and it worked out alright for him.

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      • #4
        I live about a mile from GSS Speaker Repair Service in North Hollywood, CA. They re-coned my Advent Home stereo speakers, and my Jensen speaker in my Epiphone combo amp. I was happy with the job they did. I guess I'll go over there tomorrow and ask about it. BTW, they have rubber surrounds. I can get a new speaker for about $60, so it might not be worth repairing, on the other hand, I paid $50 each for these speakers in '66, so they are probably better.
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        • #5
          I don't recall Jensen MI line ever using foam surrounds and I'm not sure I've ever seen a butyl surround on an MI Jensen either. Butyl is generally pretty stable, don't know about 40 years though. To replace a surround properly, the dust cap needs to be removed, the vc accurately shimmed and then once cured a new dust cap needs to be installed. Doing it any other way is half-assed so beware of the hacks out there.
          -------------------------------------------------------------------------------------------------------------------------------------------------------------------
          Former product development engineer: Genz Benz, a KMC Music/Fender Musical Instruments Company, continuing factory level product support and service for Genz Benz

          Currently product development engineer: Mesa Boogie

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          • #6
            Ya I was going to say. I think if it's the surround, it really means it needs a complete recone (hey stuff dries out after that many years). If they are really those vintage speakers, I'd guess they would have a pretty high resale value if they were reconed using factory spec stuff (somebody somewhere has the kits :-) so it might be worth it anyway.
            J.R. Previously jrble

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            • #7
              Hey Jeff

              Have you measured the resistance of the cabs to rule out any differences in the speakers themselves? Speakers usually don't fail and end up at a lesser volume. There may be nothing wrong. The speakers could be different and/or they could be wired differently.
              Don Boomer

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              • #8
                It wasn't a wiring problem. I tested the speakers individually, and there was a dramatic difference in volume.

                I also just got back from GSS where I left if for repair. The cone was frozen. The guy said it was due to a magnet shift. He offered to fix it "good as new" for $75. I figured it was better to fix a vintage Jensen speaker that cost me $50 nearly 50 years ago then buy a new $60 speaker.

                BTW, I thought it had a rubber surround, but all I saw was paper.
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                • #9
                  Does he plan on fixing it without reconing it? Better get a guarantee and bounce it a few times once you get it back. I have shifted a few magnets in my days and you can do it without reckoning the speaker, but it's a crap shoot (and you can easily do it yourself)
                  Don Boomer

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                  • #10
                    I did bring up re-coning. I think he'll make that decision when he works on it. I reminded him that the cones were old, but in retrospect, I don't know if he thought I wanted to keep the nearly 50 year old original vintage paper, or if I was concerned about it being so old. I trust him to make the right decision. I'll have it back in about a week.
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                    • #11
                      Shifted magnets (pole pieces) are impossible to repair properly (and reliably) without demagging the speaker, doing a lot of surface prep, using the proper adhesives, and then remagging the speaker. $75 is a bargain IMO.

                      I was pretty sure it wasn't a foam/butyl surround.

                      I would also be suspect of the remaining speakers, pole piece failure tends to run with manufacturing lots. Age can also be a factor. You fall into both catagories.
                      -------------------------------------------------------------------------------------------------------------------------------------------------------------------
                      Former product development engineer: Genz Benz, a KMC Music/Fender Musical Instruments Company, continuing factory level product support and service for Genz Benz

                      Currently product development engineer: Mesa Boogie

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                      • #12
                        Good advice all around. And I can't help mentioning the squirrel photobomb.
                        .....

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                        • #13
                          I was born in 1966 ..... probably '66 speaker today will be well worth
                          Last edited by Kalina2; 08-22-2014, 02:52 PM.

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                          • #14
                            Originally posted by Craig Vecchione View Post
                            Good advice all around. And I can't help mentioning the squirrel photobomb.
                            I forgot about that. I took pictures throughout the project for my web page, and Nutzy photobombed most of them
                            http://www.jeffreyleites.com/SpeakerCab01.html
                            My Web Site - Tunes - Pictures - Guitar Projects - Native American Style Flute Projects - Hard Rock Cafe Guitar Pins
                            My Eclectic YouTube Channel

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