Is amp tech a moron?

[popandslap]

Okay here's the deal. On my GK Neo 212 cab, only ONE of the woofers makes a buzzing noise when high notes are played either high up on the fretboard or lower on the D and G strings. This occurs when the volume is turned up slightly, enough to make the room rumble. The person who services GK amps and cabs through Guitar Center tried saying there was nothing wrong and that it was my bass. First of all, my bass is setup right, there is NO fret buzz that could be causing this problem. Also, if it was fret buzz, wouldn't both of my woofers be buzzing? The tech also said it could be dirty power, again, wouldn't both of my woofers be buzzing? I'm getting really fed up here, I know it's not the grill because i've taken it off and this issue is still present. Both woofers are tightly screwed in, i've even removed the woofers to ensure there is nothing causing the buzzing. What do you think the problem is?

[SpamBot]

Tighten all screws you can find, then report back.

[dan stanton]

Look for tiny tears in your speakers. Since you have diagnosed it yourself, don't ask the tech, tell them what you need, don't ask.

[popandslap]

Originally Posted by SpamBot

Tighten all screws you can find, then report back.

I've already done this, everything else is riveted.

[popandslap]

Originally Posted by dan stanton

Look for tiny tears in your speakers. Since you have diagnosed it yourself, don't ask the tech, tell them what you need, don't ask.

There aren't any tiny tears from what I can tell, but my thoughts were what if the voice coil is damaged? The only way to tell would be to remove the dust cap right? My drummer who works for GC is siding with the amp guy trying to say that he has all of the contracts for all GC's in the state, NY, MA, and RI which I think is complete B.S. because he told me this guy works out of his house which is supposedly modified to be a shop.

[dmusic148]

Well, it SEEMS obvious that it must be the one woofer, or something else in the cab. But for the heck of it, try a different bass, and amp, just as a 'sanity check.'
It COULD just be a loose connection on the noisy speaker.
Or, the woofer has overheated, distorting the voice coil, which makes it rub. These problems will often be more noticeable when playing certain notes, as you have observed.

[David1234]

First, play a CD through the amp to be "extra super" sure it isn't something else in your bass.

Next, see if there's an air gap in the cab's handles or the cab's input sockets. You can get a chuffing kind of rattle sound on big notes from an air gap, that would seem to localise it more near one woofer than the other. You just have to play big notes at it til you find it (or download a tone generator such as this so you can send it a 100Hz sine from your PC to test with)

Another thing to consider - I've previously had a rattle caused by a physically loose tweeter. The rattle was still there when the tweeter was defeated, so it didn't seem to be a tweeter problem til I held the cab up and shook it, and recognised the rattle for what it was. This probably isn't your problem, but it's worth checking the possibility. Good luck!

[Calaverasgrande]

It is rare but I have seen this happen when the leads from the terminal on the woofer frame to the actual VC rub against each other. There can also be a stray piece of speaker cable causing this.
Or in my case, the finger foam that someone installed inside of my GK4112 was physically rubbing against the speaker cones! I trimmed it back and made a note to self to purchase some poly batting.

As far as te amp tech, my amp tech works out of his house (converted warehouse) and does damn good work. The amount and variety of tools they need kind of necessitates that they all be in one place.
Now someone can totally shoot me down on this, but IMHO amp techs working out of their own garages are generally better than the ones I have encountered in stores.
A good amp tech doesnt need to man a counter at a guitar store to pay his bills. All he has to do is bias amps and do mods/repairs very well.
Unfortunately if you are trying to get warranty service you may be stuck with this guy, and he doesnt dound like he cares to help. Often warranty service contracts arent very profitable, but are entered into so they can perform the non-warranty repairs as an authorized service center and get referrals from the manufacturer.

[popandslap]

Originally Posted by Calaverasgrande

It is rare but I have seen this happen when the leads from the terminal on the woofer frame to the actual VC rub against each other. There can also be a stray piece of speaker cable causing this.
Or in my case, the finger foam that someone installed inside of my GK4112 was physically rubbing against the speaker cones! I trimmed it back and made a note to self to purchase some poly batting.

As far as te amp tech, my amp tech works out of his house (converted warehouse) and does damn good work. The amount and variety of tools they need kind of necessitates that they all be in one place.
Now someone can totally shoot me down on this, but IMHO amp techs working out of their own garages are generally better than the ones I have encountered in stores.
A good amp tech doesnt need to man a counter at a guitar store to pay his bills. All he has to do is bias amps and do mods/repairs very well.
Unfortunately if you are trying to get warranty service you may be stuck with this guy, and he doesnt dound like he cares to help. Often warranty service contracts arent very profitable, but are entered into so they can perform the non-warranty repairs as an authorized service center and get referrals from the manufacturer.

I'm not saying guys who work out of modified homes or garages are bad, I'm saying that it seems like a load when my buddy tells me he has the contracts for ALL guitar center stores in CT as well as the other states mentioned. You're trying to tell me he's the only one authorized to do repairs out of 4 states? I think that's a little fishy.

[James Judson]

Voice coil needs replacement. Been there done that. Used to happen on a regular basis to me in the 60's and 70's. Running 2 dual 15 cabs I'd replace one about one a year.

To test, gently push the cone up and down and listen for the rub. Push at the edge in different spots (kinda tweaking the cone to one side). Compare to the good speaker.

[joegeezer]

Change your battery.

[T-Bird]

Hi.

Hard to tell whether he's a moron, a third party description is never too trustworthy .

Every tech I know of tests speakers (and amps as well) with signal generators, test-CD's, synths, music program, etc. for a reason. The reason obviously being to eliminate the possibility of signal source affecting the test result. If the tech actually does that much work as he claims, he probably also monitors the output SPL.
If the speaker (or an amp) falls within the manufacturers parameters = it's good. Just a fact of life.

If a speaker or an amp does pass the test doesn't mean it's necessarily without problems. Getting any warranty work done in that case is a really slim possibility though, as far as the manufacturer is concerned, everything checks ok.

Other than the "rub-test", the NEO's are a bit hard to diagnose mechanically as the heat sink doesn't necessarily provide a flat reference surface as most of the traditional speakers do. A bent frame is a regular problem with narrow air gap motors on stamped steel baskets. While a NEO motor is considerably lighter, it still has mass, and on stamped steel baskets bending is a possibility.

You can make simple test rig by using Your amp & cab and a PC based signal generator. Find out the buzzing frequencies and find out where the buzz comes from.

Regards
Sam

[derridiandrift]

Originally Posted by David1234

First, play a CD through the amp to be "extra super" sure it isn't something else in your bass.

This is the best way to eliminate the possibility of the problem being with your bass or any other bass. Play it at a reasonable volume, then put your ear by each driver to determine which one is pooched.

[Jaco who?]

I can't tell you what's really wrong; I'm always amazed at people thousands of miles away who apparently can, but you could check the tinned wires that come out of the back of the terminal connector to see if they rub on the cone of the driver, and if GK is chinsey enough to use spade connectors, squish 'em down with some pliers before you squeeze the onto the terminals, or just say f' it and solder them on. Run on sentence structure of the day...

[billfitzmaurice]

Originally Posted by popandslap

Okay here's the deal. On my GK Neo 212 cab, only ONE of the woofers makes a buzzing noise when high notes are played either high up on the fretboard or lower on the D and G strings.... What do you think the problem is?

The tech is either too lazy to test the drivers individually or he doesn't know what to test for, or both. Meaningful testing requires taking the drivers out of the cab. BTW, most techs have extensive training in electronics but little, if any, with speakers. At the very least anyone who claims expertise with speakers would know how to do re-coning. Therefore look for a reconing shop, they would have the expertise to find the problem and fix it.

[Jim Campbell]

Originally Posted by billfitzmaurice

The tech is either too lazy to test the drivers individually or he doesn't know what to test for, or both. Meaningful testing requires taking the drivers out of the cab. BTW, most techs have extensive training in electronics but little, if any, with speakers. At the very least anyone who claims expertise with speakers would know how to do re-coning. Therefore look for a reconing shop, they would have the expertise to find the problem and fix it.

i dunno...it doesn't say much about what opportunities the tech has had to check it out,or even if he's seen it in person....the op seems a tad quick on the draw to assume said tech is a moron,and it's unclear if the op might not be the most pleasant guy to deal with....

there are lots of possible things that could be wrong and eliminating the variables by the op is not mentioned anywhere.....hearing a buzz and automatically assuming a speaker warranty problem without first doing a few preliminary checks is not likely to endear anyone to any tech business,as they now have to spend time checking for problems that may be elsewhere in the signal path,and may not occur with the cab itself......

perhaps a rundown of what checks have and have not been done by the op is in order before it is assumed that the tech is a moron....

[AltGrendel]

Originally Posted by Jim Campbell

i dunno...it doesn't say much about what opportunities the tech has had to check it out,or even if he's seen it in person....the op seems a tad quick on the draw to assume said tech is a moron,and it's unclear if the op might not be the most pleasant guy to deal with....

He's probably frustrated because he thinks the tech isn't listening to him.

How well he's explaining the problem is another issue. Techs only like to play 20 questions for so long, so I think the OP now doing homework that he should have done before taking the amp in.

How much tact he's using is something else again.

[Jim Campbell]

Originally Posted by AltGrendel

He's probably frustrated because he thinks the tech isn't listening to him.

How well he's explaining the problem is another issue. Techs only like to play 20 questions for so long, so I think the OP now doing homework that he should have done before taking the amp in.

How much tact he's using is something else again.

yeah....i can almost hear the conversation....

[billfitzmaurice]

Originally Posted by Jim Campbell

perhaps a rundown of what checks have and have not been done by the op is in order before it is assumed that the tech is a moron....

If the tech thinks that one driver working poorly while the other works fine is the fault of the bass then I tend to agree more with the OPs opinion.

[Gearhead43]

Originally Posted by billfitzmaurice

If the tech thinks that one driver working poorly while the other works fine is the fault of the bass then I tend to agree more with the OPs opinion.

+1 Guy sounds kinda shade-tree to me.