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Revisiting Jim Rogers JR149s

Discussion in 'classic' started by Tony L, Mar 21, 2013.

  1. Operajulian

    Operajulian Opera Julian

    Well with all these conversations going on - I went back in with the soldering iron and replaced all the capacitors with a set of replacements from Falcon. They have been in an envelope for a couple of years , pending the motivation to take apart a pair of speakers that sounded great to me.
    Let's play a few vinyl albums ( in honour of RSD ) and see what and if there is a difference :)

    PS I went out to a couple of shops and did not buy a single record today.....I might take a more longer look tomorrow when the fuss has died down.
     
  2. Tony L

    Tony L Administrator

    [​IMG]

    Got my 50A fuses! These have to be pretty much the same as bypassing entirely as the “fuse” bit looks more solid than a PCB track or component lead! I’ve just stuck them in anyway...
     
  3. ToTo Man

    ToTo Man the band not the dog

    Nice one! Ordered mine on Tuesday so will hopefully have them for some weekend playtime. What do they sound like, 50A fuses? ;)
     
  4. davidsrsb

    davidsrsb pfm Member

    50A fuses should sound just like wire links
     
    ToTo Man likes this.
  5. davidsrsb

    davidsrsb pfm Member

    I don't know why JR put the fuse in the input, rather than the tweeter output. Where it is will not protect the tweeter as it has to be rated to handle the bass power.
     
  6. Tony L

    Tony L Administrator

    I’ve no desire to take them out, the system really is sounding good!

    PS It wouldn’t surprise me if people were blowing B110s rather than T27s, I’d have thought that would die first at a party or whatever. The T27 can cope with far louder 3-way systems such as Kef Concertos etc.
     
  7. davidsrsb

    davidsrsb pfm Member

    Usually 3 ways cross the tweeter higher. The Concerto was 3.5 kHz. Higher is an easier life.
    I suppose that the high BSC levels of the JR149 might have led to excess B110 coil excursion on warped records and deep bass
     
  8. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    I guess they will do but I would certainly solder a link across fuse holder personally. There are still contacts, which can slacken off or become tarnished. Performance is everything and appearance of zero concern for me!
     
  9. ToTo Man

    ToTo Man the band not the dog

    I'm going to dab my ends with some Caig DeOxit Gold to stave off the tarnishing process... I might try it on the fuses too! :D
     
  10. 337alant

    337alant Negatively Biased

    Why order 50A fuse just solder a piece of wire across a 1A fuse end caps if you want to leave it reversible

    alan
     
  11. ToTo Man

    ToTo Man the band not the dog

    With cerebral palsy, 50A fuses are a much easier solution for me. Saves having to ask my dad to dig out the soldering iron!
     
  12. Tony L

    Tony L Administrator

    I considered that, though assumed the heat would crack the glass.

    PS FWIW I’m now back to my initial position of thinking bypassing/uprating the fuse makes a worthwhile difference. It just sounds a bit ‘more’, and as everyone knows more is better.
     
  13. The glass will not melt but the glue holding the end caps to the glass tube will, you will need to be quick!
     
  14. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    The expanding hot air in the fuse then pushes the end caps off! Fiddly but doable.
     
  15. Tony L

    Tony L Administrator

    [​IMG]

    Just to prove it is doable here’s a bit of mains ‘twin & earth’ soldered to a pair of the 50 Amp fuses - I wonder how many Amps it is now?!

    PS Not listened to them yet...
     
  16. Woadl

    Woadl Member

    Hello, I have just purchased a pair of JR149 red logo speakers
    Although they are working fine I would like to go ahead and recap the crossover.

    Mine is a lot more simpler to the ones pictured and has among others 2x 3uf none polarised caps.
    I cannot find them anywhere only 3.3 uf, can I use those ?

    https://www.flickr.com/photos/169760958@N03/33777709118/in/dateposted-public/
    The link above is a picture of my crossover

    I am located in Perth Western Australia so my choices are limited so am looking on line

    Also I am in need of foam covers

    Thanks everyone and it’s good to see all this info on the speakers

    Cheers

    Brian
     
  17. davidsrsb

    davidsrsb pfm Member

    That is a different to the one reverse engineered above.
    Generally 3uF and 3.3uF should be a straight swap.
    If you can, make a measurement with REW or Holmimpulse to see what you are starting with.
     
  18. Marchbanks

    Marchbanks Golly, do I ever have a lot of soul!

    They look like the crossovers in the eBay speakers linked to here, which have at least one 3.3uf Elcap fitted, presumably also from new.
     
  19. davidsrsb

    davidsrsb pfm Member

    As the link/capacitor is part of the tweeter crossover, it is part of the tweeter power handling story, so it is worth replacing the link with the capacitor.
     
  20. Woadl

    Woadl Member

    Thanks for your reply’s, David are you saying to take out the wire link and insert a capacitor in there ?

    I’ll message Falcon and see what caps are in the kit that they sell for the 149’s

    At the moment they sound fine but I just want to restore them.

    Is the foam that Wilmslow Audio sell ok for these speakers ?
     

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