What’s this little thing that was rattling around in my cabinet?

Marko5657 · #1 03-12-2011, 12:44 PM

GK 212MBE. I’m guessing it has something to do with the tweeter, as that doesn’t work.

This cab sounds really bad when I hit the lower strings.

I’ve been gigging it and it stays in the band trailer, so I don’t get to just mess with it on stage, but I knew it was making some nasty noises, so I brought it home, and man, it sounds pretty bad.

I bought this used at MF, assuming it was one of the newer ones not afflicted with the cab vibration rattle I read about with the older ones, but maybe that is my problem.

Btw, any links to the fix for that rattle? I think it was a matter of putting in a brace or something.

Thanks...

delta7fred · #2 03-12-2011, 12:46 PM

That's a capacitor, probably part of the crossover. No wonder you cab sounds bad.

Marko5657 · #3 03-12-2011, 12:49 PM

So you think that this capacitor being out is the reason for the low-end distortion farting kinda sound?

delta7fred · #4 03-12-2011, 01:07 PM

I'm not familiar with the GK 212MBE cab, but it won't be helping having a cap removed.

Just a thought but maybe the reason the capacitor has broken off is because of vibration caused by a previous owner thrashing it mercilessly. Could be a voice coil is also distorted and catching on the magnet (blown speaker) causing the farting out at higher volumes.

Sorry to be vague, but it is difficult diagnosing a fault without having the cab in front of you.

billfitzmaurice · #5 03-12-2011, 01:18 PM

It is a capacitor, but not a type that would usually be used in a crossover.

Marko5657 · #6 03-12-2011, 01:18 PM

Quote:

Originally Posted by delta7fred

I'm not familiar with the GK 212MBE cab, but it won't be helping having a cap removed.

Just a thought but maybe the reason the capacitor has broken off is because of vibration caused by a previous owner thrashing it mercilessly. Could be a voice coil is also distorted and catching on the magnet (blown speaker) causing the farting out at higher volumes.

Sorry to be vague, but it is difficult diagnosing a fault without having the cab in front of you.

I understand, and appreciate your input.

I’m researching the purpose of capacitors right now, and that could very well be the problem, but advice from someone would help.

Where the capacitor wires were connected, there’s no wire sticking out for resoldering, so maybe I could just get another better one?

Again, any advice appreciated.

Marko5657 · #7 03-12-2011, 01:22 PM

Quote:

Originally Posted by billfitzmaurice

It is a capacitor, but not a type that would usually be used in a crossover.

Not sure what that means. Should I get another?

Again, even at lower volumes, the lows sound farty and distorted, not really a rattling sound to my ears.

I tightened up the speakers (one had a few loose screws), tried active and passive basses, don’t know what to do.

billfitzmaurice · #8 03-12-2011, 01:26 PM

Quote:

Originally Posted by Marko5657

Not sure what that means. Should I get another?

As far as I can tell it's not a crossover capacitor, so there's no point in getting another. Besides, how would you know where to put it?
In any event a missing crossover cap would not explain the issues you're having. It sounds like blown drivers to me. The apparently toasted tweeter also points to that.

delta7fred · #9 03-12-2011, 01:26 PM

I will bow to Bill's superior knowledge on all things cab related.

Does the GK 212MBE have ports, if it does then this cap may have nothing to do with your cab. It may just have 'found it's way in there', a bit like the tea spoon I found in my combo once.

Marko5657 · #10 03-12-2011, 01:29 PM

It’s a piezo, so I didn’t think they used crossovers.

Maybe I should disconnect one driver at a time and see if one sound good and one bad, unless they’re both blown.

Marko5657 · #11 03-12-2011, 01:32 PM

Okay, just listening to it close, one speaker is making noises and one not.

Marko5657 · #12 03-12-2011, 01:55 PM

Quote:

Originally Posted by Marko5657

Okay, just listening to it close, one speaker is making noises and one not.

I take that back. I unplugged one speaker at a time, they both sound distorted when playing the lower notes (B string mostly), and now both together seem are behaving the same together.

Marko5657 · #13 03-12-2011, 01:58 PM

Open A, even at higher volume, sound fine, even open E not too bad, mainly below that.

Does that sound like blown drivers?

bongomania · #14 03-12-2011, 02:03 PM

I have my ear right up against the computer screen, and I still can't tell exactly what it sounds like.

Since you aren't in a position to fix it yourself, not knowing where the capacitor even came from, or whether it's the cause or a symptom or unrelated; and since clearly the cab needs fixing; TAKE IT TO A REPAIR SHOP.

Marko5657 · #15 03-12-2011, 02:15 PM

Quote:

Originally Posted by bongomania

I have my ear right up against the computer screen, and I still can't tell exactly what it sounds like.

Since you aren't in a position to fix it yourself, not knowing where the capacitor even came from, or whether it's the cause or a symptom or unrelated; and since clearly the cab needs fixing; TAKE IT TO A REPAIR SHOP.

Yeah, this thread got off from just asking what the capacitor was.

Sorry ‘bout that; of course I can’t expect help with such little info.

Marko5657 · #16 03-12-2011, 02:39 PM

Update, just for the hell of it.

Took it outside just to make sure there was nothing else making the vibrating sound. It still sounded bad. I just jammed my knee against the back of the cab, and the distortion just about went away.

I guess I’ll look into bracing.

BassmanPaul · #17 03-12-2011, 02:41 PM

Quote:

Originally Posted by bongomania

I have my ear right up against the computer screen, and I still can't tell exactly what it sounds like.

That's strange!

My laptop's shaking around all over the place!

Oops - That's my knees sorry!

Got to agree with Bongo - take it to a tech.

billfitzmaurice · #18 03-12-2011, 03:27 PM

Quote:

Originally Posted by Marko5657

Update, just for the hell of it.

Took it outside just to make sure there was nothing else making the vibrating sound. It still sounded bad. I just jammed my knee against the back of the cab, and the distortion just about went away.

I guess I’ll look into bracing.

You may find this of value:
the MB212 "kit-built" project (intro.).......