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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Lounge => Topic started by: Debbie Dunkley on April 07, 2014, 09:23:57 PM

Title: JBL PRX612 noise
Post by: Debbie Dunkley on April 07, 2014, 09:23:57 PM
Not sure how long this has been going on at gigs because the noise coming from the horn is so faint and I may not have noticed it as the last few gigs with all the outside noises going on. I know it didnt happen when I bought it.
Today I set up my 2 PRX612's in my home for band rehearsal and noticed one of them has a faint high pitched frequency noise coming from the horn.  Like radio interference.  It happens regardless of whether anything is going through it. I checked cables and even changed outlets (different circuit) just in case but the sound is there as soon as it is switched on.
It is only 7 months old and has not had very much use - I use other speakers which I rotate through according to the venue size and type of music.
I am a little surprised due to the reputation these speakers have but like anything, there are no guarantees that something will not fail I suppose.
So at least I'll get it repaired FOC. Good job I have other speakers I can use while I wait.
Any ideas as to what is could be?? or is that like asking "How long is a piece of string?"

Also, my speakers are 'babied' - they are never dropped, knocked, abused or even spoken to badly......
Title: Re: JBL PRX612 noise
Post by: Tim Perry on April 07, 2014, 11:09:20 PM
Not sure how long this has been going on at gigs because the noise coming from the horn is so faint and I may not have noticed it as the last few gigs with all the outside noises going on. I know it didnt happen when I bought it.
Today I set up my 2 PRX612's in my home for band rehearsal and noticed one of them has a faint high pitched frequency noise coming from the horn.  Like radio interference.  It happens regardless of whether anything is going through it. I checked cables and even changed outlets (different circuit) just in case but the sound is there as soon as it is switched on.
It is only 7 months old and has not had very much use - I use other speakers which I rotate through according to the venue size and type of music.
I am a little surprised due to the reputation these speakers have but like anything, there are no guarantees that something will not fail I suppose.
So at least I'll get it repaired FOC. Good job I have other speakers I can use while I wait.
Any ideas as to what is could be?? or is that like asking "How long is a piece of string?"

Also, my speakers are 'babied' - they are never dropped, knocked, abused or even spoken to badly......

One of my PRX'e went bad with what sound like the same problem, an intermittent crackle.  After a couple week a authorized serve center is now working on it... supposedly. The extreme hassle of getting this stuff fixed makes me leery of ever investing in this company's product again.   
Title: Re: JBL PRX612 noise
Post by: Cailen Waddell on April 08, 2014, 07:54:18 AM
Debbie, when you look at authorized service centers in NC, the best choices are Durham and Greensboro, and Greensboro is far and above the best choice IMHO. You can PM me if you need more details....
Title: Re: JBL PRX612 noise
Post by: Tim McCulloch on April 08, 2014, 09:49:36 AM
Debbie, when you look at authorized service centers in NC, the best choices are Durham and Greensboro, and Greensboro is far and above the best choice IMHO. You can PM me if you need more details....

Greensboro is a vastly under-rated city.  I had a touring gig that took me there roughly twice a year and looked forward to it each time.
Title: Re: JBL PRX612 noise
Post by: Debbie Dunkley on April 08, 2014, 10:35:15 AM
One of my PRX'e went bad with what sound like the same problem, an intermittent crackle.  After a couple week a authorized serve center is now working on it... supposedly. The extreme hassle of getting this stuff fixed makes me leery of ever investing in this company's product again.

Might be the same thing although my sound is constant -not a crackle.
I have been using JBL products for many years and they have always served me well so this won't affect my loyalty - UNLESS I get the runaround in trying to get it fixed.
Title: Re: JBL PRX612 noise
Post by: Tim Perry on April 08, 2014, 04:42:34 PM
Might be the same thing although my sound is constant -not a crackle.
I have been using JBL products for many years and they have always served me well so this won't affect my loyalty - UNLESS I get the runaround in trying to get it fixed.

The service center not only demanded the receipt but a copy of the original factory sales invoice.  They also wanted me to ship the entire speaker not just the power module.

I am working through the retail outlet where I bought them. 

Hope you have a good service experience.
 
Title: Re: JBL PRX612 noise
Post by: Debbie Dunkley on April 08, 2014, 04:54:57 PM
The service center not only demanded the receipt but a copy of the original factory sales invoice.  They also wanted me to ship the entire speaker not just the power module.

I am working through the retail outlet where I bought them. 

Hope you have a good service experience.

Interesting. ...
So I called the service center I intend to use which has been recommended to me. The gentleman I spoke with seemed very accommodating and asked that I bring in a copy of the sales receipt only along with the speaker. He advised that if the amp is the problem, they will remove it from the cab and send just the amp to JBL. If it is anything else,  they will repair it there. (I have a feeling it is the amp)

According to the JBL website, if you choose to go directly through them, they require the whole unit sent back to them - not the amp module. That is if it was you or me - not an authorized repair shop. The guy mentioned that if that is the case, it will take a few weeks.....

Going to drop it off tomorrow and we will see.
Title: Re: JBL PRX612 noise
Post by: Bob Leonard on April 08, 2014, 05:31:06 PM
The service center not only demanded the receipt but a copy of the original factory sales invoice.  They also wanted me to ship the entire speaker not just the power module.

I am working through the retail outlet where I bought them. 

Hope you have a good service experience.

Which is generally an indication they are not a fully authorized JBL service center.
Title: Re: JBL PRX612 noise
Post by: Debbie Dunkley on April 08, 2014, 06:55:07 PM

Which is generally an indication they are not a fully authorized JBL service center.

That's a worry...Tim did you check the JBL website to see if these guys are authorized? If so, I wonder why they would need anything more than the sales receipt.
Title: Re: JBL PRX612 noise
Post by: Tim Perry on April 08, 2014, 07:09:54 PM
That's a worry...Tim did you check the JBL website to see if these guys are authorized? If so, I wonder why they would need anything more than the sales receipt.

They are on the list.
Title: Re: JBL PRX612 noise
Post by: Debbie Dunkley on April 08, 2014, 07:19:46 PM
They are on the list.

Then you should be fine. If you don't feel comfortable with the way things are being handled, you could contact JBL.
I had a question regarding speaker crossover frequencies a few weeks ago when I purchased my PRX718xlf and I went on to the JBL website and asked them my question.
The next day I had one of the techs call me to help me which I thought was really good customer service. It made me feel more confident about my purchase. Gave me the impression they are a company who cares so if you get any issues, I'd call or email JBL.
Title: Re: JBL PRX612 noise
Post by: Cailen Waddell on April 08, 2014, 07:34:17 PM
There are different things you can be on the list for.....
Title: Re: JBL PRX612 noise
Post by: Ray Aberle on April 09, 2014, 12:44:42 AM
According to the JBL website, if you choose to go directly through them, they require the whole unit sent back to them - not the amp module. That is if it was you or me - not an authorized repair shop.

I had one of my VRX boxes go out on me last summer. I contacted JBL directly to discuss the warranty repair-- since they're self-powered, I had the same concerns you did. They directed me to send them just the amp module, in order to save on the shipping expense. That might have been, of course, since I was confident/qualified enough to remove it myself. :) I'd also sent them pictures of the fried-out part of the inside of the module, since I was working on troubleshooting it myself first.

(Of course, they had some weirdness where they thought it'd been exposed to moisture, and that was what caused the fault-- which didn't make sense since these boxes live on casters, and aren't used in the rain. It was weird. Fortunately, I was able to get them to take care of me still! Thanks, JBL!)

-Ray
Title: Re: JBL PRX612 noise
Post by: Debbie Dunkley on April 09, 2014, 02:36:32 PM
I had one of my VRX boxes go out on me last summer. I contacted JBL directly to discuss the warranty repair-- since they're self-powered, I had the same concerns you did. They directed me to send them just the amp module, in order to save on the shipping expense. That might have been, of course, since I was confident/qualified enough to remove it myself. :) I'd also sent them pictures of the fried-out part of the inside of the module, since I was working on troubleshooting it myself first.

(Of course, they had some weirdness where they thought it'd been exposed to moisture, and that was what caused the fault-- which didn't make sense since these boxes live on casters, and aren't used in the rain. It was weird. Fortunately, I was able to get them to take care of me still! Thanks, JBL!)

-Ray

It makes sense that they don't want everybody taking apart speakers and causing even more problems. Good to know that they realized you knew what you were doing and that they took care of you.
I dont foresee any problems and I'll report back as and when I have an update.  I dropped it off today and the 'JBL person' will be in on monday to look at it.
Title: Re: JBL PRX612 noise
Post by: Debbie Dunkley on April 30, 2014, 10:37:20 AM
They are on the list.

Hey Tim...did you get your speaker sorted out without any problems??

Mine has been in since 4/10. The guy called me the next week and said they had the speaker playing music all day but couldn't here the noise I had described. I explained AGAIN that the noise can only be heard when there is NOTHING playing through it. He said they had misunderstood and in that case they would remove the amp module and send it in to JBL.
So I called  last week to follow up and he said they had changed their minds and were going to fix it themselves instead as it seems there is an earthing problem. . I still haven't heard anything.....
Considering I was told that it would take a few weeks IF it had to go back to JBL, I am a little disappointed that it is taking this long for an in-house - apparently straight forward repair.
Title: Re: JBL PRX612 noise
Post by: Tim Perry on May 01, 2014, 12:35:56 AM
Hey Tim...did you get your speaker sorted out without any problems??

Nope.  I hope to get the module back some day, either fixed or not. In the meantime I'm getting more calls for gigs then I can execute.

 
Title: Re: JBL PRX612 noise
Post by: Debbie Dunkley on May 01, 2014, 05:10:21 PM
Ironically after having posted my comment yesterday,  I got a call this afternoon from the service center letting me know the speaker is ready for pick-up.  So....3 weeks. Not too bad I suppose especially as I have 3 more of these I can use but I can fully understand the frustration of some people if income relies on these going down. Maybe there just aren't enough JBL authorized centers which causes long waiting times....

The fault by the way was 2 capacitors had gone bad on the power stage. (Did I word that correctly?)....Really?....7 month old speakers....NEVER pushed hard, in fact hardly used at all because these were kept in my studio for monitors 95% of the time.... The diagnosis corresponds with the symptoms because the noise I heard did not change with the gain control and was not affected by anything being connected. Does anyone know what could cause this?
Title: Re: JBL PRX612 noise
Post by: Cailen Waddell on May 01, 2014, 05:52:40 PM
Bad capacitors from the factory.   Glad it worked out... But yeah it's disappointing when cluster met service is lacking. Especially in this customer service driven industry...
Title: Re: JBL PRX612 noise
Post by: Tim Perry on May 01, 2014, 05:53:01 PM
Ironically after having posted my comment yesterday,  I got a call this afternoon from the service center letting me know the speaker is ready for pick-up.  So....3 weeks. Not too bad I suppose especially as I have 3 more of these I can use but I can fully understand the frustration of some people if income relies on these going down. Maybe there just aren't enough JBL authorized centers which causes long waiting times....

The fault by the way was 2 capacitors had gone bad on the power stage. (Did I word that correctly?)....Really?....7 month old speakers....NEVER pushed hard, in fact hardly used at all because these were kept in my studio for monitors 95% of the time.... The diagnosis corresponds with the symptoms because the noise I heard did not change with the gain control and was not affected by anything being connected. Does anyone know what could cause this?

Probably nothing you did (other then just use the things).  Parts can go bad just because they want to.
Title: Re: JBL PRX612 noise
Post by: Debbie Dunkley on May 01, 2014, 07:28:43 PM
OK...good. Thanks for the replies Tim and Cailen.  If it is simply one of those things - then that's what it is.
At least it is fixed. The noise it was making was very subtle and to be honest had no effect on the sound it was reproducing at all. Who knows how long it may have lasted or how long it had been going on (maybe from new???)...... but once I noticed it, my concern was to catch whatever was causing it BEFORE it fails. And that was bound to be early in the night at an important show right??
Title: Re: JBL PRX612 noise
Post by: Debbie Dunkley on May 08, 2014, 10:35:12 PM
Picked up the speaker on monday. The noise is still there !!
However, just the fact it has been tested,  something was found to be wrong and replaced and nothing else shows as defective makes me feel a little  better. If the tech can find nothing actually 'wrong' with the speaker to cause the sound other than those 2 leaking capacitors then I suppose I have confidence that it doesn't have  a failing component.
I haven't called the shop to tell them because if they can't hear the noise then it would be a tough sell at this point ( the noise is very quiet) - AND they did work on it after all. In fact I would think the noise was the normal sound of the speaker at idle if I didn't own 3 others that don't sound that way....
I tested it with some nice loud music and it sounds good......oh well...
Title: Re: JBL PRX612 noise
Post by: Tom Burgess on May 09, 2014, 01:02:55 PM
Picked up the speaker on monday. The noise is still there !!
However, just the fact it has been tested,  something was found to be wrong and replaced and nothing else shows as defective makes me feel a little  better. If the tech can find nothing actually 'wrong' with the speaker to cause the sound other than those 2 leaking capacitors then I suppose I have confidence that it doesn't have  a failing component.
I haven't called the shop to tell them because if they can't hear the noise then it would be a tough sell at this point ( the noise is very quiet) - AND they did work on it after all. In fact I would think the noise was the normal sound of the speaker at idle if I didn't own 3 others that don't sound that way....
I tested it with some nice loud music and it sounds good......oh well...
Have you considered taking it back along with one of your other 612's so that you can demonstrate the difference for them?  I'd like to think they'd be very interested in solving the issue.
Title: Re: JBL PRX612 noise
Post by: Steve Garris on May 09, 2014, 02:47:41 PM
Or perhaps you could shoot a video, demonstrating the noisy one compared to the others?
Title: Re: JBL PRX612 noise
Post by: Debbie Dunkley on May 09, 2014, 10:45:56 PM
Have you considered taking it back along with one of your other 612's so that you can demonstrate the difference for them?  I'd like to think they'd be very interested in solving the issue.

I would if the place was local. My husband travels around for work and was the one to drop off and pick up. The JBL tech is only there 2 days a week so he'd have to arrange sales calls on one of those 2 days and dedicate the time to demo the 2 speakers...probably aint gonna happen :(
Title: Re: JBL PRX612 noise
Post by: Debbie Dunkley on May 09, 2014, 10:47:12 PM
Or perhaps you could shoot a video, demonstrating the noisy one compared to the others?

This sounds doable.... I might put something together and send the file to them ahead of time so they know what I mean..
Title: Re: JBL PRX612 noise
Post by: Karen Furno on May 10, 2014, 03:27:56 PM
Earlier this year I worked on some Avid SC48 consoles that had noise problems on some of the input channels.  After some inspired poking around, I discovered that the noise only occurred when phantom power was turned on for that channel.  We are not an Avid authorized repair center, so the customer agreed to swap out the whole input module with a reworked one from Avid.  When the new one came in, I noticed the input DC blocking caps were now electrolytic units instead of the high-dollar metalized polyester ones in the original unit.  Not having a schematic, or access to Avid techs, I can only surmise that the blocking caps were leaking ever so slightly when the 48 VDC phantom hit them.  They probably met every manufacturer spec for leakage, but because they were used in a very high gain audio path, and we are fussy about 100+ dB signal to noise, they added unacceptable noise in our application.  It's funny too, because they were high quality WIMA caps, at around $2.75 apiece in the Mouser catalog, and the electrolytics were likely around 50 cents.  Even funnier, when our own SC48 started exhibiting the same noise symptoms, Avid replaced the modules under warranty, and guess what, the new ones had WIMA caps in them.  I guess WIMA had a batch run that were slightly more noisy than usual.
Title: Re: JBL PRX612 noise
Post by: Tim Perry on May 11, 2014, 11:25:32 AM
Nope.  I hope to get the module back some day, either fixed or not. In the meantime I'm getting more calls for gigs then I can execute.

Well here is the result:  The module was returned fully functional. No parts were needed. Apparently reseating the preamp module took care of the issue.

While the speaker was (barely) in warranty, the electronics were not, yet the work was done no charge. I wasn't even charged for shipping.

I ran speaker six hours for testing.

The symptoms were an intermittent scratchy noise  usually when cold and disappearing when the unit warmed up. the symptoms progressively got worse reaching the point of unusability.

Down time was 11 weeks. "Turnaround" time by the service shop was probably about 10 weeks.  Return shipping within the same state was a full week.
Title: Re: JBL PRX612 noise
Post by: Debbie Dunkley on May 11, 2014, 11:45:10 PM
Well here is the result:  The module was returned fully functional. No parts were needed. Apparently reseating the preamp module took care of the issue.

While the speaker was (barely) in warranty, the electronics were not, yet the work was done no charge. I wasn't even charged for shipping.

I ran speaker six hours for testing.

The symptoms were an intermittent scratchy noise  usually when cold and disappearing when the unit warmed up. the symptoms progressively got worse reaching the point of unusability.

Down time was 11 weeks. "Turnaround" time by the service shop was probably about 10 weeks.  Return shipping within the same state was a full week.

Well I'm pleased you are back in business Tim.... but 10/11 weeks turnaround seems excessive to me under any circumstances....