Loudspeakers EV XZA-1

[urban79]

So I have two of these in a music rehearsal space. In the three years or so we've owned them, I have replaced the amp modules twice, and now I have the same symptoms for a third time. Whenever it is plugged in and turned on, I get a constant clicking, about 72 BPM. It doesn't matter the level, there is no change in volume of the clicking.

The last time these were replaced under warranty, but that has now run out, and I certainly don't want to shell out $200-300 every couple of years per speaker. Any thoughts on what might be causing it?

Thanks!

Chris

 

[rwhealey]

That's an unusual failure rate for any of the major loudspeaker manufacturers - I could see one amp failure as being a manufacturing defect, but after three failures I would start looking for an external cause.

What are the environmental conditions? Have you metered the AC power to look for things like severe over/under voltage? Is someone abusing them without you knowing?

 

[TimMc]

So I have two of these in a music rehearsal space. In the three years or so we've owned them, I have replaced the amp modules twice, and now I have the same symptoms for a third time. Whenever it is plugged in and turned on, I get a constant clicking, about 72 BPM. It doesn't matter the level, there is no change in volume of the clicking.

The last time these were replaced under warranty, but that has now run out, and I certainly don't want to shell out $200-300 every couple of years per speaker. Any thoughts on what might be causing it?

Thanks!

Chris

Chris, does it make that sound with nothing plugged into the input... only powered up and turned on?

 

[MNicolai]

What happens if you disconnect the speaker drivers from the amplifier and plug the amp into power? If you still hear noise, a component on the PCB is probably physically vibrating. Maybe an inductor.

If the sound is actually coming through the speaker driver though, that might indicate a faulty capacitor or transistor.

If it makes you feel any better, I played a similar game with JBL's powered VRX cabinets a few years back, but because of the RMA process they wanted us to send the entire cabinets back instead of just the Crown amp modules. Went back and forth 3-4 times before the amp modules stopped going kaput after 20-40 hours of use. Never got a clear answer on the cause but my suspicion was a flawed component in the manufacturing process.

 

[urban79]

That's an unusual failure rate for any of the major loudspeaker manufacturers - I could see one amp failure as being a manufacturing defect, but after three failures I would start looking for an external cause.

What are the environmental conditions? Have you metered the AC power to look for things like severe over/under voltage? Is someone abusing them without you knowing?

That is my thought as well - anytime I meter the power, it has been at the 120 mark, but it would be hard to say that something isn't happening over a period of time... I don't believe anyone is abusing them - the two of us that use the classroom are pretty careful about it - I've never found the volume on the speaker set extremely high which was my first expectation on the failure.

Chris, does it make that sound with nothing plugged into the input... only powered up and turned on?

Yes, even with nothing plugged in to either the line-level or microphone input it still clicks.

What happens if you disconnect the speaker drivers from the amplifier and plug the amp into power? If you still hear noise, a component on the PCB is probably physically vibrating. Maybe an inductor.

If the sound is actually coming through the speaker driver though, that might indicate a faulty capacitor or transistor.

If it makes you feel any better, I played a similar game with JBL's powered VRX cabinets a few years back, but because of the RMA process they wanted us to send the entire cabinets back instead of just the Crown amp modules. Went back and forth 3-4 times before the amp modules stopped going kaput after 20-40 hours of use. Never got a clear answer on the cause but my suspicion was a flawed component in the manufacturing process.

I have not been inside yet - wanted to get some ideas of what could be wrong (and therefore how to prevent it in the future) before I go poking around. I'll let you know what I find.

 

[TimMc]

Chris, I had an installation in a small club - no live bands, no DJs, primarily a background music system. I had to replace woofers twice.
We finally learned that the cleaning crew was playing music at Full Tilt Boogie at 7am when there was nobody in the club. We found out when an adjacent business owner mentioned that the music was loud when he came to work every morning.

 

[urban79]

Ok, so the module does not click on its own - it must be the speaker driver; which begs the question is it the module that actually needs replacing? Or something else?

 

[urban79]

Another aspect to this, these speakers are on constantly - could this cause premature failure? I have been asking for a switch to be installed as otherwise I require a ladder to get to the speakers, but it's been two years with no progress...

 

[MNicolai]

It's probably still an issue with the amp module, but more likely caused by a circuit board failure than a vibrating component. If it was an issue with the driver or the cone I'd expect the clicking to be exacerbated at higher SPL's when you're driving it.

I'd visually inspect the components for anything obviously defunct. Make sure the capacitors aren't oozing any conductive goo, that the transistors and other components do not look scorched or emit any kind of burnt electronics smell.

Power -- depends. Some powered speakers go into an energy saving mode and auto-off when the input signal falls below a certain threshold for a long enough stretch of time. If this is the case, you would probably notice the speakers go full mute when their idle and flip on when you drive them, and then hiss a little noise for a 5-10 minutes after you've stopped driving them before going full mute again. If they don't have an energy saving mode, the power supply certainly could fritz out sooner over time. I'd still expect you to get more than a couple years out of these things, but then again they're super entry-level speakers.

If you have another speaker of the same model that is working properly you could rule out the speaker drivers by swapping the amp modules between the cabinets and seeing if the clicking follows the drivers or follows the amps. I'm reasonably confident it's the amp module though.

 

[rwhealey]

Ok, so the module does not click on its own - it must be the speaker driver; which begs the question is it the module that actually needs replacing? Or something else?

Another idea - when I dropped one of my Zx1s, the plastic threads for the screws holding the front and back of the cabinet broke and the speaker began to make a clicking noise when driven. Unlike other plastic EV speakers of the same era, the Zx1's compression driver is not supported by the back of the cabinet, only the horn. This makes them quite a bit more fragile.

Have you taken them completely apart to verify that the cabinet is in physical working order?