Blown speaker, I think?

Discussion in 'Amps and Cabs [BG]' started by Jacob M, Jun 29, 2008.

  1. Jacob M

    Jacob M

    Aug 28, 2004
    New York
    So I was practicing with my band today, using my Gallien-Krueger 400 RB 1x15, and it just straight up stopped making noise. I had the Volume, Master and Boost all below 5. I had been using a Seymour Duncan Pickup Booster earlier, but wasn't at the time.

    I initially thought the pedal had just run out of batteries, but after fiddling around found out that the amp just straight up wasn't working. I didn't hear any loud noise before it died, it just stopped making noises all together, no weak noises, nothing that sounds weird or wrong, just complete silence. However, the XLR out still works.

    Does this mean that I just completely blew out my speaker playing at about 4? I had been keeping this amp out in my garage, where it gets rather hot during the day, could this have contributed to it? Might it be something besides a blow speaker?
  2. ThunderStik

    ThunderStik Guest

    Jun 25, 2001
    Claremore OK.
    Generally when a driver goes it will give you notice before hand. There are sounds that it will put out that will be a warning sign (most of the time).

    If your pre and XLR are still working I would do the following.

    1) Pull off your speaker grill and LIGHTLY push around the outside of the center of the speaker cone with one finger on each side of the dust cover ( the little round bubble in the center of the speaker). Just like giving the peace sign then push in with the bubble in between the 2 finger.

    If its nice, easy and smooth chances are your driver is ok. If its rough and gravely feeling or wont move at all then the driver is gone.

    2) If the driver is good I would pull it out slowly and check the wires connecting to the rear of it. I have had them come loose on me a few times in the past. If this is the case you may look at a habit I developed a long time ago which is no matter what cab I get I always open up the box and solder the connections up. This will make sure it doesnt happen again and this includes during a show which greatly sucks as if you couldnt tell.
    3) If all connections are good and the speaker feels good you probably have a down power section or a loose connection in the amp itself. Take care of these things first. Then we will see where your at.
  3. ThunderStik

    ThunderStik Guest

    Jun 25, 2001
    Claremore OK.
    Not that I can think of. Once inside the amp,in the actual electronics there can be a shock hazard but not generally in what im talking about. Just be sure its unplugged and you should be golden.
  4. Jacob M

    Jacob M

    Aug 28, 2004
    New York
    It still moves, but I don't know whether to classify it as smooth or rough. It has the same texture as the rest of the speaker's surface, a little rough, sorta like construction paper.
    I assumed since it wasn't gravelly that I should go on to this step. The wires in the rear are still connected, though I don't know if the wire's just supposed to be touching anything that's metal, or if they're supposed to be touching a particular part.
    So, it appears that the dust-cover and wires are O.K., what other options do I have...
  5. vonlefty


    Jun 10, 2008
    I think they meant you should actually push the cone itself, not rub the cover. If a speaker has a mechanical failure, ( and it would have to be a fairly big one to stop working all the sudden in your case) then by pushing on the cone you should be able to feel a problem. A speaker with a mechanical problem will have a gritty or scratchy "feel" to it but more often than not the cone itself won't move very much, if at all, if it's "blown". Also, make sure the tinsel leads are still attached to the voice coil, that's another common problem.
  6. Rick Auricchio

    Rick Auricchio Registered Bass Offender Supporting Member

    It's easy to try another cabinet, even a non-bass speaker as long as you keep the level low. Either that or another amp to check your cabinet.

    Since it's either the amp or the cabinet, switch one of them to see what's up.

    As for the speaker motion when you push it: You're trying to gently push it in and out like it normally moves when it plays. You can feel a scraping inside or it's smooth.

    Note that moving smoothly doesn't guarantee it's good, but if it scrapes it's definitely bad.
  7. ThunderStik

    ThunderStik Guest

    Jun 25, 2001
    Claremore OK.
    Ok, as for speaker "feel" what your trying to gauge is piston movement as the speaker moves in and out. The center of the driver should move in and out freely. Basically your checking for free movement in the motor. Make sure of the feel of this.

    There should be 2 wires connected to the 2 posts on the rear of the driver. These are connected right? Also make sure those 2 wires are connected at the head unit.

    If you are sure of the above,

    How old is your amp? Do you still have a warranty? If so just take it in to have it looked at.

    If not, I would pull the head section out and poke around for any loose wireing. Give a good look over and make sure you dont see anything that looks burnt or loose.

    Once you have the head section out (its alot easier than it sounds) you can actually plug in your speker and a bass and the amp and play with the head section out. While doing this I would give it a good shake and some tender "love taps" to make sure it not a loose connection or anything that you can see going wrong.

    If you still have nothing its time to send it to a repair person. I would however find another driver (speaker cab) to aattach it to since your not real sure what its supposed to feel like. This way you can make sure its not the driver itself.

    Once you have done this it will be alot cheaper to ship just the head unit as opposed to the whole cab.
  8. Jacob M

    Jacob M

    Aug 28, 2004
    New York
    Ok, it moves in and out fine, I don't know what kind of range of motion is expected, but it's not stiff, though i do get resistance after a small bit of movement.

    Yeah, they seem to be connected fine.

    Warrantee was 2 years, I bought it in March of '06, so no dice.
    I guess I'll get going on this.
  9. Pilgrim

    Pilgrim Supporting Member

    Sounds like the head, not the speaker. Check for a blown fuse.

    And that means: look FIRST in the owner's manual for the head, which you of course have retained and carefully filed...or if bought used, you went online and printed it out, then filed it.
  10. Jacob M

    Jacob M

    Aug 28, 2004
    New York
    So I plugged the FX out into another amp and I got results; this is my only bass amp, so I don't have a cab to try to power legitimately, but this pretty much shows that the head isn't the problem, right? 1 thing wrong with the head though is that the cooling fan doesn't work, it just gave a very weak attempt at a start and stayed still while I had the FX out going through a guitar amp.

    So, it seems that I pretty much just have to buy a new speaker, which is kinda a good opportunity to just improve my sound anyway.
  11. ThunderStik

    ThunderStik Guest

    Jun 25, 2001
    Claremore OK.
    Not really because the power section of the head could be bad. Thats why I said find another speaker, just about any other speaker to confirm.
  12. Jacob M

    Jacob M

    Aug 28, 2004
    New York
    Wouldn't there be a danger of under/overlading the speaker and ****ing up another one? Could I plug a cable right from the head into the input of another amp?
  13. Dragonlord

    Dragonlord Rocks Around The Glocks

    Aug 30, 2000
    Greece, Europe
    This may sound stupid, but did you check the speaker cable? I recently thought I had killed my glockenklang cab when I played 2 octaves below a low B with a HOG and it died (no sound at all), and it turned out to be the stupid cable... don't know how it died since it has worked fine for 2 years and I never touch it, but it did.
  14. ggunn


    Aug 30, 2006
    Austin, TX
    The cooling fan is there for a reason, and a fan going out can cause the power section to overheat. The FX out works, but that only checks the preamp section of the amp. You need to:

    Power your speaker with another amp.


    Power another speaker with your amp.

    The will tell you if the prob is with the amp or the speaker, and your recovery strategy very much depends on the result of that test. It should be the very first thing you do, before you start poking around on the speaker cone, opening up the amp, or anything else.
  15. Active or passive bass? :smug:
  16. ThunderStik

    ThunderStik Guest

    Jun 25, 2001
    Claremore OK.

    I dont agree with this. As he is working on a combo amp most of the time you are not afforded speaker jacks. This means chances are good you will have to pull the speaker out to test it anyway. By "poking around" on the driver many times you can tell if its blown.

    Jacob, at low volumes you should not hurt anything your just looking for signal/sound to see if the driver works or not.

    Your not trying to run another amp your trying to test your speaker itself and the amp itself independant of each other. You can believe and do what you want im just trying to help out man.

    As mentioned above the if the fan is not working you have burned up the amp but maybe just could be a fuse or something. So look for those things and check them out. Keep us posted
  17. Jacob M

    Jacob M

    Aug 28, 2004
    New York
    OK, well I'll test out the driver later tonight probably when I get an extra amp to fiddle with.

    Sorry if I sounded combatative or anything, honestly I know next to nothing about amps and I'm just trying to avoid breaking anything further.

    So just to get this clear, if I take my 280 watt amp that was running into an 8ohm speaker and run it through a 4 ohm speaker rated for 150 watts, I was under the impression that I could damage/break that speaker. Are you saying that if I keep the volume low enough, I can do this?

    I called G-K and they said that the fan only turns on after a long while, once the amp has heated up, and that the movement I witnessed was normal, so I'm thinking the fan is actually working and that it's likely to be the speaker. However, I'd been storing the amp in a very hot garage, so I suppose whatever damage heat might do could've been done even if the fan works properly.

    Later tonight I'm gonna have access to another amp to fiddle with so I'll report back.
  18. DO NOT plug your speaker output into another amps input - you will blow the amps preamp section (at the least).

    You need to find a speaker to plug your head into. As long as you are at a low volume, you will not blow up another speaker. You only need enough volume to confirm that signal is making it out of the power amp section of your head.

    The test you already did (from the FX loop) only confirms that the preamp section is still working.
  19. Jacob M

    Jacob M

    Aug 28, 2004
    New York
    Passive; Seymour Duncan Vintage P-Bass pickup being used at the time.
  20. Cool. Just ruling out a dead battery in an active bass.