Dating Speaker from B-15S

Discussion in 'Amps and Cabs [BG]' started by Turbocharbo, Dec 20, 2019.


  1. Turbocharbo

    Turbocharbo Supporting Member

    Feb 16, 2005
    Hey guys

    Wondering if someone can help me find more info on this square magnet speaker found in my late 70s B-15S? It looks like a CTS but I can't find "137" written anywhere.

    Thanks!
     

    Attached Files:

  2. Turbocharbo

    Turbocharbo Supporting Member

    Feb 16, 2005
    Never mind - "67" is the code for Eminence and apparently they replaced CTS at some point in the 70s. Looks like this one was made 40th week of 1978 which lines up with the era of the amp (black screen print, rounded corners on head).

    Anyone know if these are well regarded speakers? It does sound really nice.
     
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  3. AGCurry

    AGCurry Supporting Member

    Jun 29, 2005
    St. Louis
    I think the only difference between the CTS and the Eminence is the brand name; it is as though Eminence absorbed CTS and continued to make the speaker. Someone please correct me if you know otherwise.

    These are well-regarded speakers for the B-15. I have tried four different speakers in my B-15N (JBL D140, Altec 421, Jensen C15L, and a Weber Neo). Even though Ampeg offered the JBL and the Altec as upgrades, none of my replacement attempts sounded as good as the original square-magnet driver, so I reinstalled it.

    Of course, "good" is highly subjective. For me, "good" was equivalent to "how a B-15 is supposed to sound." Not particularly high fidelity, yet punchy and creamy. I think it has something to do with the unridged and very stiff cone.

    They will not handle much power and may not work so well for other amps.
     
    Last edited: Dec 20, 2019
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  4. two fingers

    two fingers Opinionated blowhard. But not mad about it. Gold Supporting Member

    Feb 7, 2005
    Eastern NC USA
    Yeah with that amp, let it do what it does at moderate/low volumes and mic that puppy. The speaker is part of its charm.
     
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  5. BassmanPaul

    BassmanPaul Inactive

    in mine I tried a JBL 2205 and an Altec something or other. Both were very nice but the original square magnet driver was a tad better in my view.
     
  6. Turbocharbo

    Turbocharbo Supporting Member

    Feb 16, 2005
    Great! I plan on using the B-15S for live gigs at moderate to loud volumes.

    I own a '66 B-15N that I use for studio and it currently has an Eminence Delta 15A which I quite like. Do you recommend I swap the two speakers? I don't need the headroom with the N as much as I need it with the S. So, square magnet Eminence in the N and Delta 15A in the S makes sense?
     
  7. El Güero

    El Güero Inactive

    Oct 5, 2015
    I'd guess that had more to do with the Emi being a better match for that particularcab.

    The D-140F is my favorite sounding bass speaker. Kind of weak by today's standards, but it has the best sound (for me). I give the Altec 418B second place, and it doubles as a mighty fine 15" for guitar.
     
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  8. AGCurry

    AGCurry Supporting Member

    Jun 29, 2005
    St. Louis
    From the perspective of power handling, the swap would make sense, since the S makes more power. But you "quite like" the Delta 15, so as long as you're careful with volume, you should be okay as is.
     
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  9. Turbocharbo

    Turbocharbo Supporting Member

    Feb 16, 2005
    Do you know if a ´78 square magnet CTS is similar to a 60s one? I ask because I heard these came with the B-15N in the 60s. I would much prefer my B-15N to be original (ish) and have the more efficient driver in my live rig.
     
  10. 210superair

    210superair

    Sep 10, 2019
    Dating a speaker?

    I've dated worse....
     
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  11. 40Hz

    40Hz Supporting Member

    May 24, 2006
    home
    I’ve got the square magnet CTS in my B-15N.

    I’ve heard other speakers in B-15 amps. I found I always preferred the tone of the CTS.
     
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  12. 40Hz

    40Hz Supporting Member

    May 24, 2006
    home
    Then go unload the CTS and use whatever you want. Your CTS will net a quick sale on the used market. There are more than enough B-15 owners who will be happy to take it off your hands.
     
  13. Turbocharbo

    Turbocharbo Supporting Member

    Feb 16, 2005
    I’m saying I want to put the CTS in my B-15N and the Delta 15A in my B-15S.
     
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  14. 40Hz

    40Hz Supporting Member

    May 24, 2006
    home
    Apologies! Guess I missed that.

    The CTS in the B-15N is a marriage made in heaven to my ears. Really like mine.

    Can’t comment in the proposed B-15S/Delta combination. Never played one of those. So I’ll defer to those who have and are therefore qualified to respond to that part of the question. :)
     
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  15. Turbocharbo

    Turbocharbo Supporting Member

    Feb 16, 2005
    It's actually a '78 square magnet Eminence but apparently it's the same thing as the CTS from the early years. Good to know that those work well with B-15N!
     
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  16. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Yamaha, Ampeg, Line 6, EMG
    CTS wasn't absorbed. They just changed their focus and got out of making speakers. They're still around and thriving very well, making lots of electronic parts, including many of the potentiometers we use in our guitars and amps.

    Fun fact...Bob Gault, the founder of Eminence, used to work for CTS and started Eminence in 1966 with a 3-speaker a day commitment from Ampeg for their B-18's.
     
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  17. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Yamaha, Ampeg, Line 6, EMG
    Oh, regarding the difference between CTS Ampeg speakers of the 60's and 70's, as well as the Delta 15a...

    The 60's Ampeg CTS's are a little brighter than 70's CTS's. I don't know how that B-15S Eminence sounds compared to them, but I used to have a 77 B-15N with a 71 CTS in it, and I couldn't use them interchangeably. Tried it once, and the 71 CTS was too dark in the 60's cab and the 66 Ampeg labeled CTS I got for my 64 B-15N cab was too midscoopy for my tastes in the 77 cab, and it's all because of the cab differences, because nobody would ever accuse my 64 cab of sound midscoopy.

    And the Delta 15a is a dead ringer tonally for the 66's CTS, so I would probably avoid putting either in a B-15S cab.
     
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  18. dan1952

    dan1952 Commercial User

    Jun 27, 2012
    Anderson IN
    Artist Endorsement with Supro Huntington Basses / Owner, Dan's Music, Inc..
    Ampeg, more than any other company that I know of, was great at matching the speakers to the amp. Leave any B15 as stock as possible, and if you need more clean volume, buy an SVT.
     
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  19. Raw N Low

    Raw N Low If I can't hear it, hopefully I'll feel it Supporting Member

    Jul 16, 2009
    Denver, Colorado
    I recently acquired a '79 B-15s from a friend with a EVM 15b series II. The speaker sounds pretty darn good paired up and I don't plan on changing it for now.

    I'm curious to try out the Altec variant first comparison.
     
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  20. beans-on-toast

    beans-on-toast

    Aug 7, 2008
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    Primary TB Assistant

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