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Speaker cabinet for a Fender Twin Reverb Custom 15.

Discussion in 'Amp Central Station' started by Tommasogezz, Sep 3, 2013.

  1. Tommasogezz

    Tommasogezz TDPRI Member

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    I own a Fender Twin Custom 15, essentially an 85 watt twin reissue 65 with an Eminence 15 speaker. I'm perfectly happy with the sound of this amp: extremely clean, fantastic low end and sparkling high end..
    The only missing side, just to find one, is the middle range..
    That's why I'm thinking about pairing a 2x12 cabinet to the 15 speaker.
    I already divided the amp into head and cabinet so I'd like to know what kind of 12 speaker you suggest to combine with the 15 or just to use alone with the head.. Finally I want to have three one speaker cabinets: one with the original 15 and two with the 12 speakers.
    I'm thinking about the EVM12L or the Eminence Swamp Thang.
    The amp is a 4 ohm.
    The 12s are both 8 ohm.
    The in-built 15 is a 4 ohm.
    How to combine them without blowing the transformer?
    Any suggestion about the speakers?

    Any help is welcome!
     
  2. marshman

    marshman Friend of Leo's

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    Well, the Twin Reverb comes with Jensen C12Ks as standard, so that might be a logical place to start. I've heard very few bad comments about Jensens' Neo 12" speakers, so that would save you a few pounds, and I'd like to think that the Jensen speakers would be easy to find as they are made in Italy.

    Hopefully, someone with a better understanding of transformer/impedance interactions will help with the other part of your question.
     
  3. waparker4

    waparker4 Doctor of Teleocity

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    Might have to buy an 8 ohm 15 speaker, wire them all parallel for 2.67 ohms.
     
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  5. Tommasogezz

    Tommasogezz TDPRI Member

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    I'll think about a couple of Jensen.. Thank you
    Anyway you must know that in Italy we can find almost everything...
     
  6. Tommasogezz

    Tommasogezz TDPRI Member

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    Thanks a lot. If I plug just an 8 ohm speaker on a 4 ohm amp how will it work?
     
    Last edited: Sep 3, 2013
  7. waparker4

    waparker4 Doctor of Teleocity

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    Fender amps are suppose to be able to handle a mismatch up to a factor of 2. However I'd rather mismatch on the low side. Ymmv
     
  8. eugenedunn

    eugenedunn Friend of Leo's

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    Tube amps behave better with a mismatch of higher impedance, due to the "blow back" voltage..... If you're gonna buy a couple new 12-inch speakers, make them each 16 ohms...then, when you wire them in parallel, the cabinet will be 8-ohm impedance total.

    That means, you could conceivably run it daisychained simultaneously with the other 15-inch speaker for more sonic bliss (a total 4-ohm load to your amp).
     
  9. waparker4

    waparker4 Doctor of Teleocity

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    I believe you have it reversed. Lower speaker load is safer.

    http://www.geofex.com/tubeampfaq/taffram.htm

    Go to Q: Why do I have to match speakers to the output impedance of the amp? and Extended A: It's almost never low impedance that kills an OT, it's too high an impedance.


    Even so , you want to be careful what loads speakers you are mixing and matching, because their ohm rating determines how much of the amp's power they will dissipate. You (may not) don't want a situation where some of the speakers are doing all the work and the remaining speakers are relatively quiet.
     
  10. eugenedunn

    eugenedunn Friend of Leo's

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    Sorry, you're right, fly back voltage is the phenomenon that's due to higher impedance mismatch..... I meant to refer to low impedances being hard on tubes because of over-dissappation. I believe tubes are the weaker link....so....
     
  11. Tommasogezz

    Tommasogezz TDPRI Member

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    So what's or what are the right combinations between
    One 15 speaker 4 ohm
    One 12 speaker 8 ohm
    One 12 speaker 8 ohm

    I already know the 15 works(...)
    The two 12 together in parallel will be 4 ohm total (8x8)/(8+8)
    The 15 with just one 12 in parallel will be (8x4)/(8+4)=2,66...7
    Is there a way to plug just one 12 cabinet??

    Any other suggestion about speakers type and brand?
    What do you think about the EVM and the Eminence Swamp Thang?
    Thanks a lot!!!
     
  12. eugenedunn

    eugenedunn Friend of Leo's

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    One of the coolest "Swiss Army Knives of Connectivity" is the Weber Z-Matcher. It's an impedance matching transformer that allows you to dial in the desired impedance of the speaker loads you're connecting to almost any conventional amplifier..... check it out at Weber VST.

    It also comes with a line out jack for extra connectivity options. I have enjoyed using mine for years.
     

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  13. waparker4

    waparker4 Doctor of Teleocity

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    I don't know, that's why I suggested an 8 ohm 15" driver..

    One 15 4 ohm in series with
    Two parallel 12 speakers 8/2 = 4 ohms

    makes a total load of 8 ohms. Parallel would make 2 ohms.

    The pair of speakers will get half the power (1/4 for each) and the 15 will get the other half of the power. By my calculations (which I think are correct :rolleyes: ... _)
     
  14. Tommasogezz

    Tommasogezz TDPRI Member

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    Is there anyone experienced with extra cabinet on a Fender Twin?
    How to increase the mid response on a 15" jbl copy speaker?
    Can a 1x 12 cabinet solve the "problem"??
    Any advice will be appreciated!!
     
  15. eugenedunn

    eugenedunn Friend of Leo's

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    I've played through a couple rigs that are similar to what you're talking about and never found a particular lack of midrange.....

    A silverface Fender Vibrasonic (essentially a 100-watt Fender Twin with 15-inch JBL D130F in combo format....my buddy dropped the chassis into a head cabinet and put the JBL in a ported sealed back extension cabinet.

    A Fender Showman (essentially 85 watt Fender Twin in head format). This was paired with either a 15-inch sealed back tone-ring cabinet or my front ported sealed back cabinet loaded with an Altec 421A.

    All of these cabinets were sealed back cabinets with different types of porting..... All are fantastic sounding.....plenty of bass and full range tone. So my point is that a fuller tone is gonna come from a ported sealed back cabinet. A sealed cabinet does tend to damp the speaker and give punchier bass...you can EQ appropriately without farting out and that also means your midrange is gonna sound stronger, without causing boominess.
     
  16. Tommasogezz

    Tommasogezz TDPRI Member

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    Wow Eugenedunn!
    That is what I call a real player suggestion!
    Thank you very much!
    I think I'm gonna bring the cabinet to my tech and ask him to seal the back by a removable piece of wood! This way I can easily remove it when I rec
     
  17. Tommasogezz

    Tommasogezz TDPRI Member

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    Wow Eugenedunn!
    That is what I call a real player suggestion!
    Thank you very much!
    I think I'm gonna bring the cabinet to my tech and ask him to seal the back by a removable piece of wood! This way I can easily remove it when I record as I also mic it from the back..
    Last two questions:
    What does it mean "ported"?... I tried to find it on the web but couldn't really understand the meaning in the sentence "ported sealed back etc.."
    A closed back instead of the opened stock cabinet will not reduce the three-dimensional sound I really love in this amp?
     
  18. JDC

    JDC Tele-Holic

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  19. marshman

    marshman Friend of Leo's

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    I'm not sure you'll be able to seal that amplifier...I presume the tubes will need fresh air circulation to prevent excessive heat buildup. If you only play the amp for 20-30 minutes at a time, it might not matter.

    'Ported' refers to specifically engineered holes in the cabinet to reinforce certain aspects of the response, can be adjusted to enhance specific ranges of the output. I have no understanding of the science involved, though.
     
  20. Tommasogezz

    Tommasogezz TDPRI Member

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    Hi Marshman,
    I started the thread writing than the combo has already been divided into head and cabinet so I don't think is going to be a problem for the valves if I seal the back of the cabinet...
    Anyway I'm a professional player and amp is on around 5 hours a day as I use it for practicing, teaching, recording and of course gigging.
    That's why I want to improve the sound. I'm not that kind of gear collector with 10 guitars and 5 amps for playing in the bedroom..
    I'd really love suggestion from people who owns the same amp I know and solved the problem before me: how to increase the mid response in a fender twin custom 15"??
    Thanks a lot!!!
     
  21. mabley123

    mabley123 Friend of Leo's

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    like eugenedunn says. the ev and jbl both are recomended to have a sealed ported cabinet.

    the ev and jbl both do best in a ported and tuned cabinet and both are recommended to have ported cabinets by the manufacturer.
    the thiele cabinet is 1 that is available from mesa that is made for the EV but is actually a bit small.

    an ev requires a 1.3 cubic foot cabinet ( internal measurement ). same as for a JBL D130F.
    the E series JBL requires a 1.5 cubic foot box and slightly over 4 inch ports. EV need some where around a 3 inch port.

    Ive been looking for cabinet(s) for the E120's.

    even though not ported.. hard truckers makes a nice semi open back cabinet they have told me works well with JBL's as they designed cabinets for grateful dead... and the dead used JBL speakers so the have a long experience with these speakers.

    at the moment I run 4 x 12 jbl e120's in a sealed back and ported sound city cabinet and a 69 dual showman reverb
     
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