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JBL K120

Discussion in 'Amps and Cabs [BG]' started by John 3:16, Apr 7, 2015.

  1. Has anybody used these for bass guitar? I'm thinking about using a pair of these either in two seperate cabinets or one cabinet. They are 8 ohm speakers. I mostly use tube amps. But I do periodically use my Aguilar TH500. I don't have a cabinet yet so I'd have to have one built. I really like the sound of my JBL d140's. I have 2-15 and 1-15 cabinets. So I'm thinking maybe a 2-12.
  2. Don't go there unless your anp is only 50-60 watts.
  3. Well my main amp that I use is a 70's Sunn Model T. Rated at 150 watts. Then for smaller gigs I use a Sunn Sonic 1-40. Rated at 60-80 watts.
  4. MIMike


    Jan 1, 2013
    West MI
    One of the best bass tones I ever got was with a pair of D-120's driven by my GK200MB.
    As mentioned before, be careful not to give then too much juice (volume).
  5. pfschim

    pfschim Just a Skeleton with a Jazz bass

    Apr 26, 2006
    SF Bay Area
    yep, tone is not the issue so much as power handling. To my knowledge 120's are intended for guitar, and have modest power handling specs compared to the other bass oriented JBL's. If you have not got the K120's yet, you might look for 130's instead.
  6. Bassmec


    May 9, 2008
    Ipswich UK
    Proprietor Springvale Studios
    Well that's the 12" speaker that is very, very hard to beat for midrange agility and tone, either for cleanish guitar or bass, if you want to use a pair with anything other than a lowish watt tube amp you will blow them up.
    The 12" old school JBL pair that will handle your 500 watt Tranny amp all day long is the 2206 driver but that said, I think my 2206's are a lot duller sounding than my K120's and I have an old Orange basket fender signature JBL D120f that tends to get used in studio as the go to loudspeaker to compliment the Motherload Speaker sim direct output.
    The White framed driver to the left is the Altec Lansing 417 series II, another utterly classic sounding 12" Alnico magnet speaker with an aluminium voice coil cap.:)
  7. I have an Ampeg B-15N loaded with a Altec 418B. So I am familiar with Altecs. I used to have a Ampeg B-15S loaded with a Atlec 421. That's my experience with Altecs. I really like the 418B. So I'm thinking maybe the JBL K120's would not be worth the effort to use in a bass guitar cabinet.
  8. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Power handling is very low under ~70Hz. The aluminum VC is wound with very low overhang, and the entire moving mass is very quite low so it's optimized for >100Hz really.
  9. Bassmec


    May 9, 2008
    Ipswich UK
    Proprietor Springvale Studios
    Probably better to think of the K120's as the tube powered midrange component of a bi amped bass rig based on a modern lightweight powered sub of some sort.
    I used the JBL 2206's in my old tri amp rig.
    but they really needed the 2" horn units to extend their upper mid response.
    I don't think you would need a horn with the K120's as they seem to put out a lot of treble without a tweeter.:)
    PS My excuse for the excessive Acoustic 408 4X15 was that I was in a Reggae Band back then.:)
  10. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    The K120 makes a fine 50 watt bass speaker where low end under 70 is not needed at any kind of volume. It's also a nice driver in combination with something like a 2240 or 2240, with the natural rolloff of the 2240 complementing the K120 pretty well. (yes, mixing driver sizes)
    Bassmec likes this.
  11. I've used K120's in a 4x12 cab with about 600 watts. The cab below it was another 4x12 loaded with 2206H's ( JBL 2206H 12" High-Power LF Driver ) with about 1200 watts. My K cabinet was eq'd for about 80hz and up - they give a beautiful tone like no other. That K cab of mine was one in a million. So, yes, they sound astounding for bass guitar. They are quite efficient - my cab sure was.
    Bassmec likes this.
  12. nysbob


    Sep 14, 2003
    Cincinnati OH
    People used to put those in fender twins - they could kill you. So much louder and more full range than the stock jensens. I think they'd be great to record through, where you want a little low end roll-off anyway.
    Bassmec likes this.
  13. Mojo-Man


    Feb 11, 2003
    I love JBL's. Just scored a mint, NOS, pair of JBL K140's. Can't wait to load these into a 2x15 cab.
    nysbob likes this.
  14. lhoward


    Apr 27, 2003
    Western NY State
    And to the OP also.

    I think you'll find that the K130 actually has half the xmax of the K120. I understand the sound can be very nice. I have a D130 in a custom cab I built about 30 years ago, but the xmax is only 0.76mm and I only use it for practice so I can enjoy the sound without over driving the suspension system. I use D140's, E140's, E145's and my favorite is a 2035HPL which has an xmax of 7.0 and a very low voice coil inductance (0.25), which allows a higher rolloff frequency and I need no HF driver, and it handles 300 watts.
    Check out these refs:
    http://www.jblproservice.com/pdf/thiele small parameters/theile parameters.pdf
    http://www.jblpro.com/pub/obsolete/k_series.pdf This brochure seems to identify K120 usage in cabs for guitars.

    Lloyd Howard
  15. I think I'll surpass using the JBL K120's for bass guitar in an enclosure. Though if I still had my Ampeg SB12 you better believe I'd be putting one of these in it to use.

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