I finally received the final components needed to wire up the JP2.0s and PR170s in my test baffle. I managed to mount and wire the entire left Mid/Tweeter panel. I had the JP2.0 wired with a series 20uF capactor directly to one set of binding posts and the PR170 wired directly to the other set. I connected each speaker to its own channel of my amplifier. I setup the DCX2496 with a 48db/oct LR crossover at 2.5 Khz. Everything was going fine, the speakers sounded better than I had hoped.
Then I did something really, really, really stupid. I decied I wanted to move some the wiring on the back of the speakers so I went to shut down my system. I turned of the DCX without shutting down the amp
There was a !!LOUD!! pop and I saw a blue arc in the JP2.0 Tweeter, I could see the PR170 move way beyond its limit, probably close to 5mm. The ribbon in the tweeter is destroyed. Its pushed way back out of the gap and looks like it's been stretched alot. There is also a deposit of metal where the ribbon either hit the magnet or where a spark jumped. There doesn't appear to be any physical damage to the PR170s cone or surround but I haven't had a chance to listen to it since this happened. I talked to madisound and they can replace the ribbon but they think I might have damaged the transformer as well
I know that this is a "learning hobby" but this SUCKS! I need help from the experts out there:
Anyone have a similar problem with a DCX, I hope I'm not the first bonehead to do something like this. If the DCX always pops when it turns off what happens if there is a poweroutage? Does it just blow up your speakers everytime?
I thought the 20uF cap would have protected the ribbon since its a highpass filter, I thought that was the purpose of putting it there even with digital X-overs.
What are the chances I didn't destroy the PR170? How do I check to see if it is still ok?
--Chris
Then I did something really, really, really stupid. I decied I wanted to move some the wiring on the back of the speakers so I went to shut down my system. I turned of the DCX without shutting down the amp
There was a !!LOUD!! pop and I saw a blue arc in the JP2.0 Tweeter, I could see the PR170 move way beyond its limit, probably close to 5mm. The ribbon in the tweeter is destroyed. Its pushed way back out of the gap and looks like it's been stretched alot. There is also a deposit of metal where the ribbon either hit the magnet or where a spark jumped. There doesn't appear to be any physical damage to the PR170s cone or surround but I haven't had a chance to listen to it since this happened. I talked to madisound and they can replace the ribbon but they think I might have damaged the transformer as well
I know that this is a "learning hobby" but this SUCKS! I need help from the experts out there:
Anyone have a similar problem with a DCX, I hope I'm not the first bonehead to do something like this. If the DCX always pops when it turns off what happens if there is a poweroutage? Does it just blow up your speakers everytime?
I thought the 20uF cap would have protected the ribbon since its a highpass filter, I thought that was the purpose of putting it there even with digital X-overs.
What are the chances I didn't destroy the PR170? How do I check to see if it is still ok?
--Chris
Ouch, sorry to hear about that.
Hope you get it sorted double quick and with minimal cost.
I had problems with a Behringer DSP1124 parametric EQ aka a BFD. It was wired to a sub and whilst it the noise was unpleasant, subs can take far more punishment than a treble unit. Having said that I only let it do it once and afterwards I always ensured I turned the components on and off in the correct order to avoid it happening again.
I guess you were unlucky.
Hope you get it sorted double quick and with minimal cost.
I had problems with a Behringer DSP1124 parametric EQ aka a BFD. It was wired to a sub and whilst it the noise was unpleasant, subs can take far more punishment than a treble unit. Having said that I only let it do it once and afterwards I always ensured I turned the components on and off in the correct order to avoid it happening again.
I guess you were unlucky.
gary f said:
I hope that you're right! The amp is rated at 120 watts per channel and I fear for the worst
I'll hook up just the PR170 and see if it sounds ok when I get home from work tonight.. Any suggestions how to test if it was damaged other than to listen for strange noises, distortion, compare how it sounds to the other one I bought?ShinOBIWAN said:
Yeah I should have known better than to power things up at 1:30 AM... Never thinking clearly that late at night. If its only the ribbon element it will cost $28 plus shipping according to the guys at madisound. If the transformer is blown I'll probably have to buy a new one..
What really bites is that you buy them in matched sets. Now I'll have one original and one repaired one
I'll let you guys know what I find out and try to take some pictures of the blown ribbon to post here.
--Chris
I'm using the same DCX2496 and JP-2.0 as you are. No offense, but I'm glad you made the mistake before I did. Now I'll be sure to power the Behringer off last!
As far as the 48/db LR you're using, why did you choose this over the Butterworth? I'm using my Fountek in a line array with (10) Vifa TC14 5" woofers and am not sure which filters to use. I will probably see which one sounds the best, but if we have 8th orders at our disposal, why not use them, right? Or am I wrong?
Again, sorry about your luck but thanks for posting this and helping me out.
As far as the 48/db LR you're using, why did you choose this over the Butterworth? I'm using my Fountek in a line array with (10) Vifa TC14 5" woofers and am not sure which filters to use. I will probably see which one sounds the best, but if we have 8th orders at our disposal, why not use them, right? Or am I wrong?
Again, sorry about your luck but thanks for posting this and helping me out.
The big cap mainly protects the transformer from any DC voltage that might hit it from the amp. 20uF would provide a too low frequency of filtering to have saved the ribbon.
If you have an ohmeter, you could measure the DC resistance across the terminals. If it's the same value as the other tweeter, then the xfrmr may still be OK.
If you have an ohmeter, you could measure the DC resistance across the terminals. If it's the same value as the other tweeter, then the xfrmr may still be OK.
Is this a problem with active crossovers in general or specifically with Behringer products? I would think there should be no reason why you should not be able to turn the crossover off before the amplifier. What causes this large spike of power? Is the crossover outputting a DC signal and then the amplifiers are amplifying it? I'm building an active crossed speaker right now and while I'm going to be using a computer as my crossover I'm still concerned for the health of my drivers.
I know ribbons are more fragile then dome tweeters but I use a 70uf cap on my speakers to protect my scan 97's from turn on thumps and accidents. The caps work fine and I have subjected the speakers to an accidental turn off of the active xover before the amplifier by mistake, everything survived.
tiroth said:
Yes I am using unbalanced amplifier inputs. I've shorted pins 1 and 3 on the XLR connector as stated in the manual.
ShinOBIWAN said:
Has anyone come up with a way to solve this issue? Guess I better start digging through all the DCX threads on the forum again
5th element said:
The 20uf should be a 1st order HP filter at around 1khz... I figured that would be enough to filter out alot of the low freq stuff. However I think that if the DCX had sent an impulse type function most of the energy would have transfered directly to the ribbon.
--Chris
DCX turn on turn off
Hey I'm no expert here and have only had my Behringer DCX2496 for a month or so. I am however the king of sloth and turn my equipment on and off in the order of whatever happens to be nearest my hand. Have never experienced more that a barely audible thump when turning the DCX on or off with the power amps running. You might want to check elsewhere in your system just to make sure.
Michael
Hey I'm no expert here and have only had my Behringer DCX2496 for a month or so. I am however the king of sloth and turn my equipment on and off in the order of whatever happens to be nearest my hand. Have never experienced more that a barely audible thump when turning the DCX on or off with the power amps running. You might want to check elsewhere in your system just to make sure.
Michael
Re: DCX turn on turn off
What amplifiers are you using? Are they balance/unbalanced inputs? The reason I ask is that the DCX was the first thing I turned off for the same reason you mentioned. It was closest to my hand Amps, sources, where stopped but fully powered with this happened.
--Chris
audiobot said:
What amplifiers are you using? Are they balance/unbalanced inputs? The reason I ask is that the DCX was the first thing I turned off for the same reason you mentioned. It was closest to my hand
Amps, sources, where stopped but fully powered with this happened.--Chris
Hi Chris
My first active XO was a Marchand XM1 kit and I had the same issues going with turn-off thump. I was/am pretty careful about turning things on and off in proper order, but I couldn't control brown outs and power outages - these were casuing me more distress than anything else.
I've got a different active XO and amps now and I'm also using JP2's with PR170MO's. But I also added one more step of protection to the 27mf series cap on the tweeter. I bought a nice beefy Belkin UPS and have my Ashly XO plugged into it. I've had a number of power outages since then and the shut down is smooth as silk. The UPS keeps the XO running long enough for the amp's caps to discharge and I can turn it off safely.
Just a thought if you're looking for some extra protection, but it still won't save you from the dumb audiphile stuff.
Allan
My first active XO was a Marchand XM1 kit and I had the same issues going with turn-off thump. I was/am pretty careful about turning things on and off in proper order, but I couldn't control brown outs and power outages - these were casuing me more distress than anything else.
I've got a different active XO and amps now and I'm also using JP2's with PR170MO's. But I also added one more step of protection to the 27mf series cap on the tweeter. I bought a nice beefy Belkin UPS and have my Ashly XO plugged into it. I've had a number of power outages since then and the shut down is smooth as silk. The UPS keeps the XO running long enough for the amp's caps to discharge and I can turn it off safely.
Just a thought if you're looking for some extra protection, but it still won't save you from the dumb audiphile stuff.
Allan
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