one stop boogie Posted May 30, 2010 Share Posted May 30, 2010 Hi people I have two questions firstly what are the best amps to run a pa with two LS 1200s with 2 PS15s and a system with 2 LS 1200s and 4 PS 15s. I currently use a crown Macrotech 2600 on the LS1200s and a Chevin digital quad amp on the tops utilising the two 1000 watt channels. The system sounds awsome in both configurations, However over the weekend I have appear to have blown two HF diaphragms which I find unusual as the system has never been over driven, is it possible that the horns have just come to the end of there life?? can any one advice me as to where I can get new diaphragms at a reasonable price the model number on them is Nexo 75B-8 I believe that B&C are the component suppliers, but I don't know there corresponding serial number or a decent supplier. thanks Link to comment Share on other sites More sharing options...
Simon Lewis Posted May 31, 2010 Share Posted May 31, 2010 The PS15s have the following recommended power reqiurements:Recommended Amplifiers 550 to 1200 Watts into 8 Ohms for 1 x PS15; 1000 to 1800 Watts into 4 Ohms for 2 x PS15 per channel Which model number is your Chevin amp? If it's the (analogue?) one that gives 1000W into 4 Ohms, then a single PS15 per channel is OK (600W) and a pair is OK (1000W) but at the bottom end of the required power. The key question is are you using the Nexo loudspeaker controller, and if so, are the sense terminals on the controler connected to the amplifiers? If the answer's 'yes', then bad luck - the controller usually offers reasonable protection (although the amp gain does need to be taken into account).If the answer's 'no' then... you've found out why it's needed. HF diaphragms can blow through short term overload, transients (bottoming out) and ultrasonic oscillation. If the loudspeaker is fed a distorted waveform, the LF driver will probably reproduce this without too much fuss, but the harmonics will pass to the HF (and it's quite a low frequency c/o on this box) and can fry it. Spares need to come from Nexo UK or a Nexo dealer. The HF driver is a custom unit for Nexo, and whilst it may be possible to fit a B&C diaphragm, there are several variants with different HF responses. I'd stick with the Nexo one. Simon Link to comment Share on other sites More sharing options...
one stop boogie Posted June 1, 2010 Author Share Posted June 1, 2010 The PS15s have the following recommended power reqiurements:Recommended Amplifiers 550 to 1200 Watts into 8 Ohms for 1 x PS15; 1000 to 1800 Watts into 4 Ohms for 2 x PS15 per channel Which model number is your Chevin amp? If it's the (analogue?) one that gives 1000W into 4 Ohms, then a single PS15 per channel is OK (600W) and a pair is OK (1000W) but at the bottom end of the required power. The key question is are you using the Nexo loudspeaker controller, and if so, are the sense terminals on the controler connected to the amplifiers? If the answer's 'yes', then bad luck - the controller usually offers reasonable protection (although the amp gain does need to be taken into account).If the answer's 'no' then... you've found out why it's needed. HF diaphragms can blow through short term overload, transients (bottoming out) and ultrasonic oscillation. If the loudspeaker is fed a distorted waveform, the LF driver will probably reproduce this without too much fuss, but the harmonics will pass to the HF (and it's quite a low frequency c/o on this box) and can fry it. Spares need to come from Nexo UK or a Nexo dealer. The HF driver is a custom unit for Nexo, and whilst it may be possible to fit a B&C diaphragm, there are several variants with different HF responses. I'd stick with the Nexo one. Simon A concurrent post has been automatically merged from this point on. Hi Simon and thanks for the reply, yes I do use the Nexo controller and yes the sense inputs/outputs are connected to the amps, the Chevin amp I use is the Q-BM11 as I understood this is a digital amp, I have never overdriven the PA and I am quite surprised that the horns have gone and currently prices are looking at being nearly £500 for two new diaphragms :-( Link to comment Share on other sites More sharing options...
Simon Lewis Posted June 1, 2010 Share Posted June 1, 2010 ...currently prices are looking at being nearly £500 for two new diaphragms :-(Then it's probably worth talking with the guys at Nexo, and making sure that the amp itself isn't causing problems in any way... Link to comment Share on other sites More sharing options...
one stop boogie Posted June 22, 2010 Author Share Posted June 22, 2010 ...currently prices are looking at being nearly £500 for two new diaphragms :-(Then it's probably worth talking with the guys at Nexo, and making sure that the amp itself isn't causing problems in any way... Link to comment Share on other sites More sharing options...
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