1960A Cab sounds tinny

Discussion in 'Cabinets & Speakers' started by JammanTSL100, Feb 20, 2020.

  1. JammanTSL100

    JammanTSL100 New Member

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    I have 2 1960a 412 cabs. 1 sounds great the other very tinny or thin, not much bottom chunk at all. I am comparing the cabs 1 at a time using my TSL 100 head.

    I pulled that back to make sure they both had the same speakers in them they both have the correct Celestion G12T-75's. One cab is 1999 the other is 2001 - I do not think the drastic sounding difference is normal. I have to put Bass on the TSL to max to make it sound decent.

    The only think I can think of is maybe the jack plate is causing it? I don't see much that cna go wrong with it. I tried both mono jacks and stereo and no change. Any other ideas or has anyone had the same issue with a bad jack plate? Any pointers would be appreciated.
     
  2. Micky

    Micky Well-Known Member VIP Member

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    Speakers connected out of phase
     
  3. ampmadscientist

    ampmadscientist Well-Known Member

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    You are describing a blown speaker...or cold amplifier bias.

    Take the speakers out of the cab one at a time.
    Move the speaker cone with you fingers in/out like a piston. *
    If the speaker cone scrapes when it moves in / out, it's blown.
    The speaker can also be frozen, and the cone won't move at all. This is what makes a speaker sound tinny.
    The speaker can still work, but the cone can be frozen and unable to move.

    * Move the cone to test STRAIGHT in and out, do not push the speaker cone in/out at an angle. The speaker cone only moves in 2 directions, straight in and straight out.

    When you take each speaker out, check the terminals with an ohm meter. Each 16 ohm speaker should read 12.6 ohms.

    When all the speakers are back in the cabinet and wired:
    Plug a speaker cable into the cabinet. Measure the end of the speaker cable with an ohm meter, should read 12.6 ohms for a 16 ohm cabinet.
    Touch a 9 volt battery to the end of the speaker cable.
    The speakers should make a loud POP sound.
    The speakers should all move in the same direction when you touch the battery to the end of the speaker cable. Make sure each speaker is moving the correct direction.

    End of speaker cab test.

    Today's Tip:
    Cold bias can make the amp sound like it has a blown speaker. Check the amp bias if you are experiencing these symptoms (above).

     
    Last edited: Feb 20, 2020
    marshalltsl and Adieu like this.
  4. mickeydg5

    mickeydg5 Well-Known Member

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  5. mickeydg5

    mickeydg5 Well-Known Member

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    I will go with what Micky menioned or corroded contacts and plugs. Clean everything with a lubricating electronics cleaner.

    Measure reistance through speaker cable and cabinet. If it is abnormally high then there is a bad/corroded contact or solder joint. That will make it sound dull.
     
  6. tschrama

    tschrama Well-Known Member

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    one cab is standing in the corner, while the other is next to it?

    e. g. room acoustics
     
  7. Matthews Guitars

    Matthews Guitars Well-Known Member

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    Speaker phasing. If any speaker is out of phase with the others, there goes the bass response. It's a very easy mistake to make if you're working inside the cabinet.

    Take the back off and take a photo showing the wiring to the speakers and post it here. Try to make the wiring to all four speakers as clearly visible as possible. An overall photo of all of it, and additional photos showing the wring going to the individual speakers.

    I'll bet one speaker is reversed. Or two.
     
  8. GIBSON67

    GIBSON67 Well-Known Member

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    Get out your multimeter and check everything. Could be out of phase speakers or a bad jack(connection) or possibly a blown speaker.

    My 425A stereo jack just went out the other day, those things are garbage!

    Hard wire them without the stereo jack...this could be your best tone upgrade, ever!
     
    Kinkless Tetrode likes this.
  9. Scumback Speakers

    Scumback Speakers Well-Known Member Sponsor

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    There's a VH tribute band named Fan Halen out here in LA. He got a cab cheap from GC that sounded like ass, so Dave Friedman told him to get some M75's for the VH tones he wanted. So Derek came over with his cab, I opened it up, and sure enough, a brand new Marshall 425B cab was wired out of phase on two speakers. I recrimped the spade terminals, wired it correctly, and then it sounded decent. Derek still got four M75 65w for his other cab, but he was pretty happy I fixed that one in 10 minutes.

    It just goes to show you the factory occasionally screws up. He got that cab cheap, I think he paid $400 for it with the speakers because it sounded thin and tinny.

    So I agree with Matthews Guitars, take good pics of the wiring, it's likely the speakers are wired wrong. Not sure if you have a switching plate, or what, but wiring diagrams for 4x12 cabs with a single input jack are here: http://www.scumbackspeakers.com/wire.html
     
    Kinkless Tetrode likes this.
  10. JammanTSL100

    JammanTSL100 New Member

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    THANKS EVERYONE for the responses! I found the issue. It was wired out of phase at the jack plate. It should have been wired as in the image attached -- it was red-black-black-red instead of red-black-red-black.

    Sounds great now! :)
     

    Attached Files:

  11. Matthews Guitars

    Matthews Guitars Well-Known Member

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    :agreed: I really figured it was that. Glad you got it settled out for NO COST. :applause:
     
  12. Antmax

    Antmax Well-Known Member

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    Yeah. I bought a Marshall MX212A and it was out of phase from the factory. Was lucky that I had an old speaker I wanted to swap out otherwise I would have returned it. It's incredible how terrible an out of phase cab can sound. When I bought it up on guitar forums a couple of other people had the same problem with the same model cab :(

    Made me wonder if that was half the reason the cab had meh reputation.
     
  13. DonP

    DonP Active Member

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    Oh wow. Was this a factory new cab? I have a 1998 1960A I've never been too happy with. I bought it new.
     
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  14. DonP

    DonP Active Member

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    Just an update: I checked my wiring and it was good. This 1960A cab is from 1998 and the wires are soldered in the rear "cup".

    What was wrong was I had the cable plugged into the 4 ohm instead of the 16 ohm. Sounds much better when cab and amp are both the same (duh). Luckily This was going on for only a very brief time.

    I think it has been performing correctly since new. I just wonder if a quad of G12T-75's is right for me. I like more "Chug" in my tone.
     
    Sustainium likes this.

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