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Revisiting Jim Rogers JR149s

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

  1. TonyScarlett

    TonyScarlett pfm Member

    Thanks for that reply, I'll try measuring them again tomorrow with the drive units disconnected. Listening to them now, I have to say, there doesn't seem to be any problems with them, they are sounding superb.
    Unfortunately my 2nd system is in the bedroom which is the coldest room in my flat so they haven't had much use since I recapped the crossovers last Autumn. Conversely the bedroom is also the coolest room in the summer so they'll see far more use in the coming months.
    I may just go ahead & replace all the resistors anyway, they are relatively cheap & I'll have the reassurance of knowing it's been done.
    TS
     
  2. Barry van O.

    Barry van O. Member

    It's been a while since my last post. I've finally finished my JR149 MKI red logo's. One of the speakers needed a new fiberboard bottom cap. There was some damage to them when I bought them but trying to disassemble that speaker further damaged it. So I decided to fabricate new top en bottom caps. It took a while to get it right but in the end I got it right. I was able to rescue the bitumen pads so I used those again.

    [​IMG] [​IMG]
     
  3. Barry van O.

    Barry van O. Member

    It's been a fun project and they are great speakers. Very detailed, dynamic en fun to listen to. I'm going to sell them on however. So if anyone is interested let me know. My next project will be a diy ls3/5a clone with a Rogers ab1 clone and in the meantime I'm enjoying my latest addition to my living room: a 7.1 Kef egg setup :)

    [​IMG] [​IMG] [​IMG] [​IMG] [​IMG] [​IMG] [​IMG] [​IMG]
     
  4. Barry van O.

    Barry van O. Member

    I've got another pair of red label JR149's with crossovers that need work. Just wondering: has anyone ever tried to use metallized polypropylene caps like Falcon does in their ls3/5a's ?
     
  5. Tony L

    Tony L Administrator

    I tried M-Cap polys and didn’t like them. Initially very impressive, i.e. clean, detailed, all the ‘hi-fi’ stuff, but the warmth and coherence was gone. I’m sure they are great caps, but the crossovers are clearly designed to sound right with electrolytics to my ears. I have two sets of crossovers so switching between them was easy. I think a mistake a lot of people make with component upgrades is not to retain a ‘control’ to reverse out to and then even kid themselves that a change is an improvement. I feel the 149 crossover is voiced the way it is with the component type factored in. It is what it is and sounds very good.

    PS Obviously none of this is a comment on the new Falcon ‘Gold Label’ LS3/5A crossovers at all as they were designed from the ground up with the new components. I would very much like to hear those one day. Shame they are so eye-wateringly expensive!
     
    torstoi likes this.
  6. Barry van O.

    Barry van O. Member

    I wonder if the reason for many brands to just use elcaps back in the day because they were dirt cheap. I've even seen a few crossovers where they used filmcaps because they ran out of a specific elcap value.
    I once used Mundorf M-caps in a set of Kef Corelli's and I didn't like them either for the same reason. I replaced them with Clarity Cap PX caps and they came straight back to life. I've tried a number of capacitors through the years but I love to use the Clarity cap px and pwa caps to replace aging elcaps. So it depends on the brand used. I might go for a second set of crossovers and do a side by side comparison. There's a guy here in the Netherlands who has a pair laying around.
     
  7. Tony L

    Tony L Administrator

    I’d let my spare pair go if interested. I’m done messing about now! The speakers are restored to as close to as-new condition as I (or I suspect anyone else) can achieve, and that was only ever my aim.
     
  8. ToTo Man

    ToTo Man the band not the dog

    Graham sent me these pics of my freshly-made bespoke JR149 mk2 grille foams today. I hope they look as good in the flesh as they do in the photos! I should have them by middle of next week. :)

    [​IMG]

    [​IMG]
     
    Barry van O. and Tony L like this.
  9. peterm

    peterm pfm Member

    Anyone looked at LesW's Avondale facebook page lately?

    His latest (of many) projects is a loudspeaker based on a low mass stainless steel enclosure, sort of D shaped.

    Sound familiar?
     
  10. Tony L

    Tony L Administrator

    Les has been playing with that type of design for decades now, can’t remember what he calls them, but I’ve heard them a few times. They are bottom ported, the tubular metal stand actually being the port! Focal drivers IIRC.
     
  11. kevinrt

    kevinrt pfm Member

    I decided to join the JR149 club. I’ve been on the lookout for some to pair with a 33/303/FM3 I have. They sound nice on the end of my Dynavector amps (Quads are still in the attic).
    Any ideas what I’ve got hold of though? I haven’t seen any others with these speaker terminals. It’s a very neat job. Not botched.
    [​IMG]1426BE88-BBC5-41BB-A5C3-1E0CA6CBE895 by Kevin Thomas, on Flickr

    [​IMG]A857BE11-E351-4CEF-BC77-BF3F7986BFA3 by Kevin Thomas, on Flickr

    [​IMG]47D5A2CA-1DCA-4C48-8371-17C299678C19 by Kevin Thomas, on Flickr

    [​IMG]12037ED2-832C-42EC-9FCF-6AC267EDB3F8 by Kevin Thomas, on Flickr

    [​IMG]C16EBE2F-C8A8-4BCF-BC80-6126A2960D78 by Kevin Thomas, on Flickr

    regards

    Kevin
    [​IMG]
     
  12. Tony L

    Tony L Administrator

    Definitely been modified by a past owner. I assume to bi-wire (ugh), so I’d expect to find some cut traces etc on the back of the circuit board. The puzzling thing is the layout of the terminals, e.g. no indication as to which are paired. I’d be inclined to pop the circuit board out and have a look at the other side and try and figure out exactly what has been done. At that point you can make a decision as to whether to try and reverse the mods out or live with them.

    PS I’m astonished anyone would embark on a mod like that without first recapping them!
     
  13. kevinrt

    kevinrt pfm Member

    Bought from a dealer via ebay, so no idea of the history. Maybe a previous owner will recognise them and respond.

    I’ll pop the boards out sometime and post a pic. If I ever choose to try and return to standard in future I’d need new covers for the bottom. Any idea where I’d find those (other than a non-working pair off ebay)?

    regards

    Kevin
     
  14. S-Man

    S-Man Kinkless Tetrode Admirer

    Not sure how they got that straight section to the bases. IIRC the originals are circular.
    It's hard to imagine that the mods would do any harm to the sound. It just doesn't look original... depends how much you care?

    If the grille foams are original, it's possible that the original electrolytics are OK. Ideally they should be measured though.
     
  15. kevinrt

    kevinrt pfm Member

    The plate for the speaker terminals is a really neat job. I’ve never heard these speakers before so no idea if this has altered the sound significantly.
    Grilles are new copies though.

    regards

    Kevin
     
  16. ToTo Man

    ToTo Man the band not the dog

    That's an interesting correlation to make, I'm curious as to your reasoning?
     
  17. S-Man

    S-Man Kinkless Tetrode Admirer

    Irrelevant since the foams are non-original, but I thought that if the speakers were stored in cool and stable conditions the electrolytics might not have dried out.
    E.g. I recapped a Cambridge Audio P50 and only one or two small elco caps, out of about 30!, were out of spec.
     
  18. TonyScarlett

    TonyScarlett pfm Member

    If it were me then so long as the mods had been done neatly I would leave them as they are, finding decent replacement bases will be next to impossible. They are probably about the only part of the JR149 that are impossible to fix!

    I would echo other peoples recommendation to replace the electrolytic caps ASAP. I've had 2 pairs of these & the caps on both were way out of spec. Just go to the Falcon Acoustics website, they sell a cap kit for around £25. I have also replaced the resistors on my current pair although it wasn't strictly necessary, none of the old ones, when I measured them off the board were very far out of spec. I just want to get this pair as good as I can, I will probably also replace the drive units with the Falcon reproductions when funds allow.

    TS
     
  19. kevinrt

    kevinrt pfm Member

    I can recognise the resistors, but which are the capacitors? The black cylinders or the bulky orange cylinders?

    My soldering is a bit rough. Perhaps not good enough for this job. Anyone know of someone in Oxford who could help?

    regards

    Kevin
     
  20. TonyScarlett

    TonyScarlett pfm Member

    The caps are the black cylindrical components marked Alcap. I'm in the Midlands, so a bit to far away to help you out. There do seem to be a lot of PFM members in the Oxfordshire area so I'm sure one of them will be able to help you out or recommend someone who can. Its definitely worth doing, it made a significant improvement to the sound on both my previous & current pair of JR149s.

    TS
     

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