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Pawn shop cabinet--refurb questions

Discussion in 'Amps and Cabs [BG]' started by emor, Jun 28, 2012.


  1. emor

    emor

    May 16, 2004
    kcmo
    I picked up this cab yesterday--my first pawn shop purchase.
    The plate on the back says that it is a Crate BE-215, 4 ohm, rated at 200 watts max.

    I don't really need another cab, but I have a couple of old (circa 1968?) JBL D140f (16 ohm) that were originally in a Sunn cab that I had in high school. I've been lugging those speakers around for decades, never quite able to part with what remains of my first gear.

    I also have a GK BP250 which is an 8 ohm minimum head that I use for rehearsals and as a backup for low volume gigs. I've been considering building a 2x15 cab for the JBLs, probably for rehearsal only, so I wouldn't have to transport a heavy cab.

    Realizing that a particular cab isn't necessarily a good match for a particular speaker, the asking price of the Crate was such that I figured I could take a chance.

    Upon further inspection after bringing it home, I found that the cab is made from OSB, a bit of a disappointment as I was hoping for plywood, but not that big of a deal considering the price. I will probably remove the rat fur, and apply either Duratex or maybe just flat black enamel paint, and probably replace the corners and install Speakon jacks. Maybe some wheels or casters as well.

    The surprise came when I removed the speakers and found that it has Carvin PS15--8 ohms, rated at 400 watts. I don't know anything about these speakers, but seems like I probably did O.K. value-wise.

    My question to those who are more knowledgeable than I am about these things, is should I put the Carvins back in and have a 4 ohm cab capable of a higher wattage head, or should I load the JBLs for a lower wattage 8 ohm cab. If I go with the JBLs, what would the maximum wattage recommendation be?

    The interior dimensions of the cab are 32 1/2" H x 22 1/2" W x 15" D.
    It has a port that angles back from 2 11/16" to about 1" over a depth of 7 3/8".

    There are some remnants of some kind of cotton batting that has been removed.
    I have some fiberglass insulation that I can use to replace, or I can purchase the mattress topper foam that I know is favored by some of the builders here (a link to the proper product would be appreciated).

    Thanks for the help.

    IMG_6245.


    IMG_6253.


    IMG_6259.


    IMG_6260.


    IMG_6263.
     
  2. john m

    john m Supporting Member

    Jan 15, 2006
    for $75 max
     
  3. emor

    emor

    May 16, 2004
    kcmo
    Close--$80.
     
  4. cableguy

    cableguy Supporting Member

    Jun 4, 2009
    North Bend, WA
    I would line the inside of the cab with some batting material or denim insulation and pop in the Carvins. At that point see what it sounds like. If nothing else use it for practice.
     
  5. If those Carvin speakers are what's in there, you have an 800 watt 4 ohm cabinet. Probably would sound pretty decent, actually. Though it could use a few braces and definitely some insulation.
     
  6. I had one of these cabs for years. Actually sounded really good with the stock speakers. Got mine dirt cheap, too. I think I paid under $200, new.
     
  7. will33

    will33

    May 22, 2006
    austin,tx
    That era of Eminence supplied Carvin OEM's are actually half-decent speakers considering their cost. Xmax around 4mm and an acceptable topend, they work alright for bass or PA. The thing is giggable with them. I'd probably hang on to them as spares or for other projects as their resale value will be very low.

    The JBL's prolly sound sweeter of course, but the bigger difference will be in spl. With the Carvins being down around 94-95 db, the JBL pair at 8 ohms will play at least as loud as the Carvin pair at 4ohms with the same amp, probably a little louder.

    I'd re-line the cab. You can use your fiberglass you already have, or the mattress foam if you don't want to deal with the itch. If the JBL's are vented, I wouldn't want loose glass fibers getting in them. Some additional bracing would be good too to stiffen up the OSB. Then probably play the JBL's in it just because. Unless they just plain don't sound good in that box.

    As far as powerhandling, just use a clean tone and gradually increase the volume until you hear the first sign of stress/distortion from the speakers and consider that the limit, whatever it may be. Not sure how to calculate tuning with the slotted/flared out port like that.
     
  8. emor

    emor

    May 16, 2004
    kcmo
    Thanks for the reply.
    The Sunn cab was lined with fiberglass insulation, so I'll probably just go with that and avoid more expense at this point.
    I can add some bracing this afternoon. I was thinking about using bracing similar to this:

    TL806constructionview.

    Any thoughts?

    I'd like to give it a test run at a jam this Saturday.
    If it sounds good, I can proceed with the cosmetic stuff.
     
  9. will33

    will33

    May 22, 2006
    austin,tx
    The box is already strongest in the corners. Crossbrace out in the middle of the panels to stop resonances/vibrations, etc. May not end up looking exactly like this diagram but you get the idea. Can use dowel, 1x1's, plywood strips, whatever you have.


    C86632BF-orig.
     
  10. emor

    emor

    May 16, 2004
    kcmo
    I can do that.
    Thanks.
     
  11. emor

    emor

    May 16, 2004
    kcmo
    Bracing:

    IMG_6267.
     
  12. will33

    will33

    May 22, 2006
    austin,tx
    That looks good, can line it and load it up. It'll be sturdier and play better too. Energy wasted vibrating the cab panels is energy not making sound.
     
  13. nice refurb on that cab, Will's advice was spot on. If you're interested in resurrecting those JBLs see if you can find an old Showman 2-15 cab or the like and drop them in there after a little bracing and porting. Two 4" ports that are 5" in length will do fine, put them between the two drivers like the old Kustom 2-15.

    I redid recently a Showman cab like that but w/two of the 8 ohm JBL D140Fs and have been enjoying the sound w/an old GK800RB, in fact it's my main bass guitar rig. And w/casters and handles it's not too bad a schlep.

    Those JBLs will take 150 watts according to JohnK_10, but I wouldn't push it much past that. Maybe find a nice tube head that's 100 watts or more and you'd be in vintage tone heaven, those drivers are too nice to be sitting in a closet.
     
  14. shaginwagin

    shaginwagin

    Apr 2, 2012
    Arizona
    Dang, nice job! That oughta work!

    Good score on that cab, hope it sounds good with your jbl's...
     
  15. emor

    emor

    May 16, 2004
    kcmo
    O.K., just to complete the sequence, here is the completed lining:

    IMG_6270.

    Unfortunately, the JBLs are going to have to wait for another day. The openings are just slightly too small and will have to be routed to accommodate the larger drivers. Like a dumbass I didn't check the fit before installing the batting.:rollno:
     

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