Gallien Krueger Neo 410-II overheating.

[JoeyFab]

My wife bought me a brand new G-K NEO 115 cab, and I blew it up at the very first gig that I used it at. It was an outdoor gig ("Farmageddon"), so I had my Ampeg SVT3-PRO/PR-410HLF rig daisy-chained to a BBE Max bass preamp/Carvin power amp/the G-K NEO 115 cab. After a short while the NEO 115 cab started to smell funny (something burning) which devolved into lots of smoke coming from the cab and it cutting out. Made for a great stage effect! Thankfully, I still had the Ampeg rig to play through to finish the gig.

Since it was still under warranty, I took it to the local G-K rep and they determined that the adhesive that was used to adhere the magnet to the 15 in. speaker basket had a gap in it and it couldn't hold the two together properly. They got a new driver from G-K and installed it, and the cab has been fine ever since (nearly 10 years now). Seems that it was a manufacturing defect, and G-K properly stood behind their product.

I hope the same thing isn't happening to you, and if it is, I hope that your cab is still under warranty.

 

[agedhorse]

They were more than fair with how they treated you imo. That's not what causes smoke and burning…

 

[JoeyFab]

They were more than fair with how they treated you imo. That's not what causes smoke and burning…

That's what they told me. Maybe they just made something up to get G-K to honor the warranty. Pretty sure I didn't overpower the cab, as the Carvin was a DCM1000 and I think I only used one channel. But maybe I bridged it, so maybe I did. Either way, I was happy it was fixed under warranty.

 

[ninjatanzen]

Some companies/employees go above and beyond. It really makes a positive difference as a customer. I'm also much more likely to continue supporting those wonderful people and businesses. Something about a two-way street?

 

[agedhorse]

Some companies/employees go above and beyond. It really makes a positive difference as a customer. I'm also much more likely to continue supporting those wonderful people and businesses. Something about a two-way street?

Agreed

 

[Kostiantyn]

he did not state anywhere that his cab is rated 4ohms. But if it is, adding a second one is no option, cause the 1001rb only goes down to 4ohms.
But assuming the cab would be 8ohms. Is it still possible to overload it by pushing more than 800w into it? The amp should have 480w at 8ohms. Does distorting it really go over 800 in this case? Seems wild to me

I have 8 ohm version. I do have a capability to add another 8 ohm cab safely.

 

[Kostiantyn]

The amp's 700 Watt rating is the amount of power it can output below a certain level of distortion. You can easily push it beyond that rating as long as you're okay with the loss in fidelity (and whatever damage it might cause).

If you are using heavy distortion effects you might not even be able to tell when you're pushing the amp beyond its rating because the distortion it adds is difficult to distinguish from the signal it was fed.

I'm certain that distortion I'm using doesn't prevent me from seeing what is happening. I keep input gain (Volume knob) very low, around 9 o'clock, there's a clip diode that helps you see if you're overdriving the input, I keep the inpuut so low it never blinks. Then I adjust the overall volume with Boost and Woofer knobs. I still think I'm not pushing it anywhere near its limits, because Boost at 10 o'clock and Woofer at 12 o'clock even not that loud.

 

[agedhorse]

I'm certain that distortion I'm using doesn't prevent me from seeing what is happening. I keep input gain (Volume knob) very low, around 9 o'clock, there's a clip diode that helps you see if you're overdriving the input, I keep the inpuut so low it never blinks. Then I adjust the overall volume with Boost and Woofer knobs. I still think I'm not pushing it anywhere near its limits, because Boost at 10 o'clock and Woofer at 12 o'clock even not that loud.

The distortion is being generated before the input circuitry, the input clip LED doesn't indicate this.

It's quite possible to overpower the crossover with heavy distortion from the DG pedal even without reaching rated power from the amp.

 

[Kostiantyn]

Here's the exercpt from the manual, I always did it like it says - set Master at noon, add volume with input Volume knob.

Yesterday I kept the Woofer low, and Volume high - no smell detected. But it was a quiet practice, so not a fair comparison. Go figure.

 

[agedhorse]

In reality, set the controls AS NEEDED for the bass you are using, the playing style and and level differences that pedals you are using requires.

The n my annual presents a starting point for the average player.

 

[TeaTime]

Ok, what happened with this? Did you find the cause? Did you find a fix? Did you fire the drummer/get the girl/change string brands?

 

[63hz]

The manual is there to teach you how to use and understand the controls. Once you know how to use them, and understand the functionality you can take over and consult the manual as necessary. As stated it is a starting place, although some industries have much better documentation than others

 

[agedhorse]

The manual is there to teach you how to use and understand the controls. Once you know how to use them, and understand the functionality you can take over and consult the manual as necessary. As stated it is a starting place, although some industries have much better documentation than others

Some manuals in this industry are much better than others too.

 

[Kostiantyn]

Ok, what happened with this? Did you find the cause? Did you find a fix? Did you fire the drummer/get the girl/change string brands?

I'm still investigating.
When I bought the cab, it had visually damaged tweeter. I realized it may had some issues before and was damaged by sloppy repair. I bought both P-Audio PHT-406 from third party seller and 1" Compression Driver 8 Ohm from official GK store (I'm sure they are the same, GK just relabels them and still calls the part PHT-406 in their invoices).

I swapped the tweeter and so far there was no weird smells after relatively loud 3 hour rehearsal.

I started using Full Range mode on cabinet, though, because in my opinion GK intetrnal crossover are set way too high, the cab crossover sound much more balanced. Not sure, I didn't measure anything scientifically and was constatntly tweaking my settings, so I may be wrong.

I'm definitely will be adding NEO 212 though, I miss something in the tone from NEO410 by itself. RBH 410 I played usually was more than enough, but it was 10 years ago so again - different bass, different place, different vibes.

 

[63hz]

I wanted to also chime in with some technical information about how you damaged your cab.

The TL;DR is that the person who suggested your distortion pedal is at fault was likely correct.

I know you weren't really understanding how that was at all possible, but it's rather simple in regards to the way that analog audio circuits work, the way power amps work, and the effect of clipping a signal on RMS voltage.

Essentially when you clip with a distortion box, fuzz, overdrive etc you can force the CABs wiring and passive electronics to receive excessive voltage. This is why gain staging is important.

For example your clip indicator on the amp head only indicates if you've clipped the amps preamp stage. It doesn't tell you anything about the total RMS output from the power amp stage.

Plug a bass directly into an amp with no distortion and play something. You will notice it is not nearly as loud as when distortion is applied.

Now apply some distortion. The level of the signal rises, meaning the cabs are now receiving higher RMS. The clip indicator is typically looking for transient spikes and is likely positioned the blink prior to any EQ controls on the amp. The clip indicator may also be looking for transient spikes rather than letting you know if you've overloaded RMS voltage.

Anytime you are adding additional gain or distortion into an amp head or in the send/return path you must be careful about RMS voltage.

Plug directly into the amp with no pedals, turn all the way up and see about how loud it is on average, not transients.

I'm guessing it probably wasn't as loud as when you had the distortion pedal and smelled smoke?

It's also possible there was a fault with your unit and the increased RMS voltage just put a spotlight on it for ya.

But yeah, too much voltage / gain can definitely damage a cab. Distortion boxes add gain.

Also, heavily distorted bass produces more of a square wave which is not ideal.

Please anyone who knows more than me feel free to correct inaccuracies

Yeah, I use a quite a bit of distortion from Darkglass B7K.

 

[JimChjones]

Also, heavily distorted bass produces more of a square wave which is not ideal.

There's nothing wrong with square waves per se. There's a lot of bollox talked about them, especially in connection with underpowering speaker myths. The feature of a square wave which may be relevant is that it contains the most energy and the most high frequency for a given amplitude.

As I understand it, and @agedhorse please correct, a conventional amplifier will put out nomore than a maximum voltage - or amplitude. A typical undistorted bass guitar signal will contain comparatively little HF, and at the amplitude limit will deliver typically power that approximates to the rated power of the amp. All well and good. OK, now feed a square wave like signal at the same amplitude. That signal contains vastly more power and vastly more HF than the undistorted bass. So if you have a speaker system sized for the rated power of the amp the "square wave" signal can overload the speaker system, especially if it contains dedicated HF units, but its nothing to do with it being a square wave, its just too much power.

 

[agedhorse]

There's nothing wrong with square waves per se. There's a lot of bollox talked about them, especially in connection with underpowering speaker myths. The feature of a square wave which may be relevant is that it contains the most energy and the most high frequency for a given amplitude.

As I understand it, and @agedhorse please correct, a conventional amplifier will put out nomore than a maximum voltage - or amplitude. A typical undistorted bass guitar signal will contain comparatively little HF, and at the amplitude limit will deliver typically power that approximates to the rated power of the amp. All well and good. OK, now feed a square wave like signal at the same amplitude. That signal contains vastly more power and vastly more HF than the undistorted bass. So if you have a speaker system sized for the rated power of the amp the "square wave" signal can overload the speaker system, especially if it contains dedicated HF units, but its nothing to do with it being a square wave, its just too much power.

Correct.

 

[Kostiantyn]

I added second 8 ohm, 2x12" NEO cabinet just in case. No weird smells so far, liked the mix of 12s and 10s.
Will continue my research and continue to monitor the situation.

 

[63hz]

There's nothing wrong with square waves per se. There's a lot of bollox talked about them, especially in connection with underpowering speaker myths. The feature of a square wave which may be relevant is that it contains the most energy and the most high frequency for a given amplitude.

As I understand it, and @agedhorse please correct, a conventional amplifier will put out nomore than a maximum voltage - or amplitude. A typical undistorted bass guitar signal will contain comparatively little HF, and at the amplitude limit will deliver typically power that approximates to the rated power of the amp. All well and good. OK, now feed a square wave like signal at the same amplitude. That signal contains vastly more power and vastly more HF than the undistorted bass. So if you have a speaker system sized for the rated power of the amp the "square wave" signal can overload the speaker system, especially if it contains dedicated HF units, but its nothing to do with it being a square wave, its just too much power.

I wasn't implying that there was anything *wrong* with square waves, just that they are not ideal.

A square wave can be created by driving a sine wave into hard clipping.

To my statement, I wasn't saying that square waves are "have something wrong with them", I was saying that speaker cones have an easier time reproducing a sine wave than they do a square wave. I personally don't think the harmonics of a square wave would damage the crossover section of a bass cab — bass amps/cabs are used for synths somewhat commonly.

In my mind, you can damage your cab in a few ways. You can damage the cones, you can overload (overheat) the cables, etc.

If you think about a waveform representing sonic energy, a square wave is like being punched in the face. Very fast, instantaneous transient rise and prolonged sustain.

To me, square waves are less than ideal because of how "hard" they are on speaker cones. And, being a side effect of hard clipping a sine wave, they are a sign that the signal being passed through has heavily clipped some previous gain stage.

A sine wave is more like gentle massage.

All that extra energy creates heat.

Yada yada, harmonics are created too, but what damages your speakers is not the harmonics but the energy

 

[agedhorse]

I wasn't implying that there was anything *wrong* with square waves, just that they are not ideal.

A square wave can be created by driving a sine wave into hard clipping.

To my statement, I wasn't saying that square waves are "have something wrong with them", I was saying that speaker cones have an easier time reproducing a sine wave than they do a square wave. I personally don't think the harmonics of a square wave would damage the crossover section of a bass cab — bass amps/cabs are used for synths somewhat commonly.

In my mind, you can damage your cab in a few ways. You can damage the cones, you can overload (overheat) the cables, etc.

If you think about a waveform representing sonic energy, a square wave is like being punched in the face. Very fast, instantaneous transient rise and prolonged sustain.

To me, square waves are less than ideal because of how "hard" they are on speaker cones. And, being a side effect of hard clipping a sine wave, they are a sign that the signal being passed through has heavily clipped some previous gain stage.

A sine wave is more like gentle massage.

All that extra energy creates heat.

Yada yada, harmonics are created too, but what damages your speakers is not the harmonics but the energy

Now we are getting into urban mythology territory. Harmonics absolutely can damage tweeters and in some cases even the crossover/L-pad.