Conference tekvax::audio

    	Any thoughts on this?
    
    	Thanks for any info.
    
    
Shawn,
    I just wonder if you have any idea on this type of the problems?
    
    
	1- When I turn the volume up to about 20-30w, my speakers get popped
	   every couple minutes.
	2- Since I have many components, so I hook everything to a power surge.
	   That's way I just power on/off from a power surge.  But, after I
	   power everything off.  15 second later am getting a staticnoise comes
	   out throught the speakers, then 2 minutes after getting a LOUD
	   popped.  Below is what I have for setup:


- AR9Ls speakers
- Klipsch Forte
- Phase Linear Model 700 Series II Amp (365 watts per channel RMS)
- Phase Linear Model 3000 Preamp
- Carver TX-11 FM Receiver
- DBX-4BX Range Expander with Impact Restoration Unit
- Soundcraftsman Equalizer DC2214
- DBX 400 Patch Bay System
- Carver C-9 Sonic Hologram Generator
- DBX 224 Noise Reduction System
- Pioneer Laser Disc
- Pioneer Tape Deck
- JVC tape Deck
- Yamaha CD
- Audio Source Surround Sound Processor
- B&O Turntable
    

    
    First of all, he has way to much stuff here!
    The popping that happens when he turns up the volume may be a blown
    speaker or it could be that something is putting out DC.
    
    The noise when he turns power off sounds normal, that is, normal for
    this system. The loud pop is his poweramp discharging the capacitors.
    
    Turning off the whole system at the power surge protector will defeat
    any muting circuits build in the preamp. A better idea is getting
    something like the Adcom ac-something that sequence the equipment. It
    first turns off all the stuff and then turns off the poweramp or maybe
    it's the othwer way around. He will have to live with problem 2 if he's 
    going to use the powersurge AC switch.
    
    To try to isolate the first problem here a few things he can do. Does
    problem 1 occur on all sources? On both channels? Disconnect all the
    stuff and start with CD connected to preamp connected to power amp and
    see if problem 1 persists. 
    
    It could be that he's speakers are rated to low. Looking back at his
    configuration I noticed that he has two pairs of speakers. Does problem
    1 occur on both pairs. What happens if he switches front and rear
    speakers?
    
    He's saying that this happens when he turns the volume up to 20-30W.
    How does he determine that he's actually using that kind of power? 
    30W in a normal system is LOUD. 
    
    
    /Peter                     
    

    re: .-2
    
    The Phase Linear amp is an older design that is known for "unusual"
    problems.  Because they do not have speaker protection built in, they
    are also known as "flame linear".  The shutdown sequence should be as
    follows:
    	1) Lower volume control to minimum.
    	2) Power off the amp.
    	3) Power off the remaining equipment.
    
    If you are only getting the popping noise at relatively high volume
    levels, I'd suspect a leaky coupling cap between the pre-amp stage and
    the power amp stage of the poweramp.
    
    Dan