LS> common AC breaker panel.  Every time ONE amp clipped, 
 LS> the line takes a drop as i figured out the amps 
 LS> output stage tried to stop the back EMF from the 
 LS> woofer and the woofer saw the amp as a complete short 
 LS> circuit on a clip blink.  This is why the breakers on 
 LS> my speaker cabinets shut off when i drive a 800 watt 
 LS> speaker at 300 watts into a bit of clipping.  When i 
 LS> run the 800 watt speaker at 900 watts into clipping, 
 LS> the breakers on the speaker cabinets do not shut off 
 LS> anymore.  Damnest problem i ever saw.
If I thought you had studied integral calc of trig functions, polar 
conversions, forms of AC instrumentation including phase relationships 
relative to power, crest factor causing variable calibration errors, and a 
few other related areas of physics and math, I could help you sort out why 
that is fairly well.  Short of that kind of background, you just have to 
trust the engineers who tell you about solid system design, including good 
components and clean support utilities.  
I'll give you a ratio that likely won't completely make sense:  (pi/2)^2
That, about 2.47, is the ratio of power between a fully clipped square wave 
and a clean sine wave of equal peak amplitude.  (Ask a calculus teacher with 
physics/electronics knowledge to explain it with some graphs.)  Adding some 
allowance for amp derating and inaccurate power measurement through indirect 
means, the numbers you think you're seeing aren't that surprising.  I suspect 
you're not seeing exactly what you think, and that the indicated 300 W is 
more than that, and the 800-900 W reading less.  
TS > LS> grilles on my yamaha 4115-II's.  With a balanced line TS > LS> i can 
push the mixer higher because i lifted the
TS > LS> negative on the balanced xlr lines.  Makes the mixer
TS > Either your equipment doesn't use normal electronic design TS > or 
you're doing something that should give less headroom,TS > not more.
 LS> Well, in english, i ran unbalanced source to balanced 
 LS> amps.  This was why i could go higher on the master 
 LS> out feeds from the mixer.  I just did the wiring like 
 LS> so:
If you're saying that jumpering input low to ground on your amps changes the 
input sensitivity, then the amp circuit has a quirk.  That doesn't make it a 
balanced feed.  I thought before you had mentioned using a pro mixer with 
balanced line outs.  With some exceptions, the line drivers commonly used 
offer 6 dB more headroom balanced than single ended on such pro gear.  Input 
stage gain isn't affected by full balanced, floating differential, or 
unbalanced operation.  Some designs are affected by other factors that can 
appear related, but require some circuit design background to understand.  
 LS> RCA jack red positive, shield negative.      XLR end, 
 LS> ground not connected but
 LS>                                              negative 
 LS> from RCA shield goes to
 LS>                                              negative 
 LS> on XLR, or ring on 1/4"
 LS>                                              plug.  
 LS> Positive from rca goes to
 LS>                                              tip of 
 LS> 1/4 balanced or positive
 LS>                                              of XLR plug.
"Tip" and "Ring" are old telephone switchboard plug terms.  They apply to the 
similar 1/4" plugs used in audio, but not to XLRs.  There are two standards 
as to which of pins 2 & 3 are + or -, often thought of as the center pin + 
for the US, and the center pin - for Europe.  Fun, fun.  That's one reason 
many pros with good budget don't mix and match brands too much.  Custom 
cables and setup are one thing in the studio, but a real PITA on the road.  
 LS> I found a standardized conflict when i ran my Crown amps, my AudioPro 
 LS> amps, and the new QSC amps i picked up.  The Crown 
 LS> wants the balanced 1/4" to have the positive on the 
 LS> ring of the 1/4" plug.  Same with the QSC.  However, 
 LS> the AudioPro amps want the positive on the 1/4" 
 LS> balanced connectors to be the tip of the plug.  Is 
 LS> there a standard for connecting racks of amplifiers 
On 1/4" Tip should be +, so that ring can short - to sleeve in some jacks.  
For XLR, see above.  There's not really a means of enforcement other than 
learning which vendors to not buy.  
 LS> together out there?  I have dealt with Yamaha 
 LS> amplifiers connected with Crown connected with 
 LS> AudioPro connected with QSC and i had to reverse the 
 LS> phase on alot of banana jacks to get the sound 
 LS> straight.
That's propbably more practical, as if you swap amps, you'll have less of a 
mess with input cables wired alike, and some bannanas flipped.  
Terry
--- Maximus 2.01wb
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