K-120 fizzy sounds

Hi Guys

I'm new to the site here. Really got the JBL bug over the last year and I've got a good little collection now after sorting out some duds from the ebay. I've got a 212 closed back guitar cabinet with a k120 and a e120, which is pretty sweet, but my favorite sound of all is the single k120 in the open back of a deluxe reverb. I love how it's just a touch less efficient than the weber Blue I had in before and to me the "full-range" sound of the speaker means you hear the "whole picture" of the guitar and amp without getting nailed in the ear whole (unpleasantly) by honky mids and upper mids.

However.... as seems to be pretty common there are some issues. When I first got the speaker there was intermittently some fizzy noise when bringing the amp to high volume and overdrive.

This brings me to nagging JBL question 1. Should these be driven to overdrive or lots of distortion? I've read alot of opinions of people saying they JBLs are good clean speakers, and not good for overdrive. I love them for OD but I'm not hurting them by pushing them full tilt on the DR am I? I can't imagine the little 18 Watter could do anything that bad... say it ain't so! It sounds so good!

Then, back to the fizz. Anyway the fizz went away at high volume, I figured perhaps there was a bit of dust or sand or glue or something rattling around in there under the dustcap, which to me explained why it would be intermittent. Then all of the sudden a month or two ago it switched. So now it sounds fizzy at low volume and the only way to clear it up is to turn up the amp volume past 6 or 7, where it's almost always fine now, and then if I bring the amp volume back down the fizzy goes away for a little while at least but will usually come back. I'm pretty sure there's no VC rub. Another plausible explanation I've ready (probably on Weber's site) is some kind of looseness where the magnet structure meets the frame. Any other ideas on what it could be or how to diagnose/repair it.

Much thanks for any insight/answers.

Could be a number of things. The problem with descriptions on the internet is one man's "fizzy" could be another man's "scratchy", another man's "buzzy"....distortion.

It could be a number of things. Debris under the dust cap that changes position with the forces within. Could be a lead wire that is frayed and on it's way out. Could be the dust screen on the magnet vent under the dust cap. Could be the dust screen at the back side of the magnet assembly.

Might be repairable... might need a recone and a recharge for you to enjoy a K120 in all it's glory. The K120 and a Deluxe Reverb is a marriage made in guitar heaven when all is right with both.

Go here for the low down on the reincarnation:
http://www.audioheritage.org/vbullet...hlight=rebirth

Thanks for the reply. I guess with an older speaker like this there's no telling what could have flaked off and be buzzing/fizzing/wheezing around in there somewhere. I guess I was hoping for "anything but a recone." I read on Weber's sight where he talked about cutting out the dustcap to clean the gap and re-gluing it. Would that be a worthwhile experiment do you think?

Otherwise I'll probably have to wait until the next year before I have a speaker budget again so I might have to let this limp along or shelve it for a while. What does a rebuild/recone cost? This one is pretty clean by comparison to the one in the link methinks. Are there any reputable re-coners in my area (MD)?

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Originally Posted by JBLuvver

Thanks for the reply. I guess with an older speaker like this there's no telling what could have flaked off and be buzzing/fizzing/wheezing around in there somewhere. I guess I was hoping for "anything but a recone." I read on Weber's sight where he talked about cutting out the dustcap to clean the gap and re-gluing it. Would that be a worthwhile experiment do you think?

Otherwise I'll probably have to wait until the next year before I have a speaker budget again so I might have to let this limp along or shelve it for a while. What does a rebuild/recone cost? This one is pretty clean by comparison to the one in the link methinks. Are there any reputable re-coners in my area (MD)?

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Check to see if one of the tinsel lead wires in the back of the unit between the terminals and cone are not sitting too close to rear of cone and rubbing or vibrating.:hmm:

Replace the leadwires ( by a real good tech ) and then diagnose. It's a common issue with the MI speakers.

Well for now the problem has disappeared. So thats good I guess... unless it decides to reappear in the middle of a gig. So I didn't even get to check if there was something to fix/adjust on the tinsel leads. But that will be my first place to look if and when it comes back. To be continued....

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Originally Posted by JBLuvver

Well for now the problem has disappeared. So thats good I guess... unless it decides to reappear in the middle of a gig. So I didn't even get to check if there was something to fix/adjust on the tinsel leads. But that will be my first place to look if and when it comes back. To be continued....

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It was a piece of debris in the gap that been displaced. It might or might not come back to fizz again.

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Originally Posted by edgewound

It was a piece of debris in the gap that been displaced. It might or might not come back to fizz again.

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Loose things floating around are no fun!:crying:

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Originally Posted by jcrobso

Loose things floating around are no fun!:crying:

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I had a customer who had many E140 broken because the reconer put a little round piece of foam to cover the inside of the vent.
Over time the foam deteriorated and the gunk lodged itself between the VC and the pole piece, forcing the VC to rub against the top plate and short out. :banghead: