Blow Fuse! [message #50561] |
Sun, 21 January 2007 08:33 |
Tuffer
Messages: 6 Registered: May 2009
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Esquire |
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Hi Guys, I have been borrowing some of your crossover designs to try and improve my speakers which are used for mainly DJ use. I am using a Beyma 15G40 and PSD2002 in a vented box. I am using an Eminence PXB2:1k6 crossover. I have created an lpad using two 15 ohm resistors and a 0.47uf cap for compensation. The resistors are wirewound and so may be inductive. See a pic below. http://www.tuffer.co.uk/cross1.jpg I have also disconnected one end of the 10uf cap on the crossover to give me a pseudo first order filter on the woofer. http://www.tuffer.co.uk/cross2.jpg Was quite happy with the results. Attenuation is perhaps a little strong. 8db might have been better. On their first proper outing however both the fuses on the crossover board blew. They were being powered by a Behringer EP2500 so about 450w max to each cab. I wasn't present when they blew but was told that they weren't being driven particularly hard. I had been using these crossovers without the lpad or mod for some time without any problems. Can anyone tell me if what I have done looks OK ? Could any of these changes increased the likelihood of overload and the fuses blowing or is it just one of those things that happen ? Should I just replace them with stock Eminence fuse or something else ? Obviously while the fuses have done there job and protected the HF drivers I wan't these cabs to be as reliable as possible. Thanks for your help.
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Re: Blow Fuse! [message #50564 is a reply to message #50563] |
Sun, 21 January 2007 13:00 |
Tuffer
Messages: 6 Registered: May 2009
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Esquire |
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Yes the lamps blew. They worked OK for about 3 hours before they went, which makes me thinks perhaps they were just doing there job. If I replaced them with 3 12v 10w lamps in parallel would this be OK or is there a better way to protect the HF driver ? Excuse my ignorance but where would I check for a dead short or an open ? I have an ohmeter.
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Re: Blow Fuse! [message #50566 is a reply to message #50565] |
Mon, 22 January 2007 02:10 |
Tuffer
Messages: 6 Registered: May 2009
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Esquire |
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Thanks for that. Any idea what power would be required for the lamps to pop ? Would adding a polyswitch in parallel with the lamps be a good idea as this seems to be a solution used a lot ? Any idea what rating ? Thanks for your help.
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Re: Blow Fuse! [message #50570 is a reply to message #50566] |
Mon, 22 January 2007 13:08 |
dB
Messages: 234 Registered: May 2009
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Master |
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Hi Tuffer, You said, adding a polyswitch in parallel with the lamps. You mean in series? PolySwitchâ„¢ is a theoretic idea, but to design (and some factories do it) a xover you need to test the finished xover over the speakers. So, after you chose one from the tables with the right triger current you have to go to the lab and blow a few PSD2002 to know the right Threshold Current. It comes out very expensive and it might not work if they are not fast enough. You can see the lights from the lamps (xover light bulbs) working and it's a much more gentle process, and your clients don't lose the sound in the process because the speaker doesn't turn off. Best Regards
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