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What is this Driver?

Discussion in 'Amps and Cabs [BG]' started by carbonfold, May 27, 2012.


  1. carbonfold

    carbonfold Supporting Member

    Oct 13, 2006
    Dallas, Texas
    Looking by the image of this square back 15 inch speaker, it looks to be a CTS 15 1969 built in 20th month. However, does anyone knows what watt and ohm rating is?

    0b927c20.jpg
     
  2. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Most drivers then were 8 ohm, some 16 ohm, almost none 4 ohm, and few handled more than 50 watts.
     
  3. carbonfold

    carbonfold Supporting Member

    Oct 13, 2006
    Dallas, Texas
    Well I have an old Kustom 215 "slantish" 2x15 cab with casters and trying to figure out it's rating. These are the drivers that it is loaded with.
     
  4. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    I think 100w power handling for the whole cab is pretty accurate.
     
  5. Most drivers Kustom used were rated as 8-16ohms as they read on the back. I have a CTS out of a 2x15 from 1972. I'll check it out and report back. ;)
     
  6. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    If you have a multimeter, you can easily figure out the impedance.
     
  7. carbonfold

    carbonfold Supporting Member

    Oct 13, 2006
    Dallas, Texas
    As you can see, nothing on the back of the drivers or CTS plate:

    b20b485a.jpg


     
  8. carbonfold

    carbonfold Supporting Member

    Oct 13, 2006
    Dallas, Texas
    It's funny how I hand fought each screw off and back on on the rear panel.... And didn't even think of getting my multimeter out to check... Ha :)



     
  9. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    That. And chances are it will fart out with more than 50w. Thermal power handling means little, driver excursion means a lot, and 60s vintage drivers had very little excursion capacity.
     
  10. carbonfold

    carbonfold Supporting Member

    Oct 13, 2006
    Dallas, Texas
    Ok, so instead of unscrewing a million screws off the back again, I just checked the ohms from the 1/4 jack. I got a reading of 6.8ohms. I assume that would be 8ohm cab "on paper" per say.

    I know when I opened the cab up that the drivers where connected in parallel. So I would assume they would be rated "on paper" as 16ohm drivers. So, honestly wouldn't this probably be a better guitar cab vs a bass cab?

    I picked up the cab when I bought my Sovtek Bassov Blues Boy 100w. Really didn't need this cab with the buy but the guy didn't want to split the sale up. It doesn't sound too bad with the head.



     

  11. Speaker impedance is completely irrelevant as far as whether it's a guitar or bass speaker.

    I gigged with an old Kustom 2x15 for a few years. Was it a great bass cab? Compared to today's cabs, nah, it wasn't a great cab. But it was built in a time when great speakers were few and far between, and its matching solid state bass head was 125 watts--which was relatively high-powered by the standards of the day. And its tone was very good for old-school Motown, country, and classic rock. So yes, it was a good bass cab! But with limitations, compared to today's cabs.

    It likely would sound pretty good with guitar too.
     
  12. carbonfold

    carbonfold Supporting Member

    Oct 13, 2006
    Dallas, Texas
    I wasn't attempting to steer toward speaker impedance in relation to guitar or bass. I actually should have been more direct.

    It was geared towards bill's comment in speaker excursion and being such a low wattage cab.


     
  13. Gotcha.

    Incidentally, the Kustoms had 3 different speaker choices. The CTS were the lowest cost, then there were JBL D140F's available, and then the 3rd choice was Altec Lansing 421A's.

    Again, the CTS speakers were "acceptable" within the limitations of its time. Driving them at low volume, with modest power, and if the low frequency EQ was flat, they would be adequate...barely...
     
  14. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    I actually like those old CTS speakers, although they sound better in some cabs than others.
     
  15. will33

    will33

    May 22, 2006
    austin,tx
    That makes it an 8ohm cab assuming both drivers are wired up and working. That wasn't all that uncommon back then, unlike today where almost all 215's are 4ohm. Many rigs back then were available with 2 big cabs like that, both to get loud enough without bottoming out, and because that PA's weren't like they are today either. Still wasn't all that uncommon for backline to carry larger gigs than we do nowdays.
     
  16. will33

    will33

    May 22, 2006
    austin,tx
    I've come across a few that have great tone, as long as you don't push them too far.
     
  17. Okie dokie.
    My speaker (1972 15" CTS) reads 8.1 ohms.

    It also has 8-16ohms stamped on the back of the magnet.
     
  18. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    8.1 ohms DCR equals about 12 ohms impedance, explaining why they called it 8-16 ohms.
     

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