TS > TS > the largest of which I know in commercial production.
TS > TS > Those use 3 phase power, and have a rated output Z of 0.67
TS > LS> Well, how well does the crown 10kw amp old up it's damping factor at
TS > 2
TS > LS> ohms?. Alot of people i know run their amps at either
TS > I don't recall.  Note that it's rated at 2/3 of an ohm, not
TS > 8 ohms.  Obviously they're good enough for the target
TS > customer mil contractors.
Quite stable, more stable than the Crest Audio 1000x series.
TS > LS> amp's thermal lights come on.  But it does not double
TS > LS> from it's 800w into 8 ohms to 1325 watts into 4 ohms
TS > LS> then to 2,000 watts into 2 ohms per channel.  Bridged
TS > Every amp is optimized for some output impedance.  Most
TS > tube amps used to be actually impedance matched to their
TS > loads.  Most solid state amps are designed to be dynamic
TS > grounds, capable of sourcing or sinking infinite current.
TS > That would make an ideal solid state amp operate almost as
TS > well into a 0.1 ohm load as into a 100 ohm load, though
TS > with calculable output ratios.  Between biasing and power
TS > supply costs, obviously that isn't true.  The point in the
TS > range at which nominal power is spec'd, the general quality
TS > of construction, and the amount of degradation at either
TS > end of the range are what vary.
TS > IOW, some cheap consumer amp may be optimized at 16 ohms,
TS > rated at 8 per FTC standards, and usable but marginal at 4
TS > ohms.  Many pro amps are optimized around 4 ohms, usable
TS > from 1 to 30.
As you know, or should know, the impedance of a speaker is a reactive load, 
never stays at one impedance.  I could visually see that happen over the 3 
year period that i've been running 120 watt RMS woofers at 800 watts RMS near 
clipping from my amps (8 ohms, dipping to 3 ohms at 50 hz, a characteristic 
that Yamaha would not explain).
TS > TS > The larger Stewart amp is about the biggest for which I see TS > a
TS > practical need in pro audio.  At 17 lbs. and 2 rack
TS > LS> 17 pound amplifier running bassbins?,  Does it have an
TS > LS> external transformer or does it run directly off the
TS > LS> 120AC without a toroid?
TS > They had to be a little more creative than that.  It does
TS > rectify direct off the mains, though with SCRs triggered to
TS > only rectify a little more energy than it needs rather than
TS > run up full power supply capacity when idling.  It then
TS > uses a supersonic DC-DC converter which provides safety
TS > isolation from the mains, and can use a physically small
TS > toroid and filters due to the high frequency.
No transformer saturation problems exist ina such an amp.  As with all my 
amps, they dim the lights when i run them, but they refuse to snap their 20 
amper per channel breakers.
TS > 10,000 W amp, 2 AWG welding cable would be TS > inadequate
TS > for speaker wire.
TS > LS> Depends on current gain.  I use cabling of no more
TS > Since when does copper wire have current gain?
Current gain from the amp, not the wire!.  My amps can carry 100 amperes per 
channel continuous, 200 amperes peak.  I tested this out about 20 times a 
year when the speaker wires short circuited and then melted the insulation on 
my 10 guage cabling.
TS > LS> than 20 feet from the speaker of 8 AWG cable for the
TS > LS> 100 sustained amperes per channel my largest amp can
TS > LS> do without going into protect if a short circuit would
TS > LS> happen (i've tried it, it melted the cable and dimmed
TS > #6 or 8 wire would likely survive.  #1 Cu would be required
TS > for that current under NEC if it were house wiring.
TS > Allowable voltage drop under NEC translates to undesirable
TS > damping factor degredation for audio.
Hmmmm.  NEC standards do not come into play on speaker cables, unless you are 
*certain* about the current gain coming out of the amp *steadily and 
continuously*.
TS > I'd rather handle 5 runs of 8-2 than one run of two banded
TS > 00 rope lay welding cables.  Change to being a movie
TS > lighting electrician if you like whipping that stuff
TS > around.
TS > TS > Now for a really big audio amp, look at the modulator
TS > TS > section of a high level modulated shortwave transmitter TS >
TS > sometime.  Those can exceed 500,000 KW audio output for a 1
TS > TS > MW TX.  (Let's just
TS > LS> RF has no room in pro audio, unless you were talking about RF amps.
TS > Do you have any concept of how a traditional shortwave
TS > transmitter is designed?  I did mention the modulator and
TS > audio output quite clearly.
TS > Facilities for broadcast are very much pro audio, to the
TS > extent that many of the pro audio trades have a user check
TS > off box for it on the card.  Shortwave is the only legal
TS > arena where it's possible to use the largest available
TS > tubes in an audio amplifier.  Using a single pair of
TS > non-custom catalog item tetrodes made by Eimac, it's
TS > possible to design a 2 megawatt audio amp (larger if you
TS > parallel tube pairs).  With operating headroom, that would
TS > be practical for a 2.5 MW transmitter emitting A3
TS > modulation.  1 MW is the largest standard catalog item
TS > transmitter made without using parallel amplifiers.
TS > You could use it to drive speakers, but the 17,500 volt
TS > plates drawing 150 amps might not be practical in the
TS > field, and the same arguments whereby several 1800 watt
TS > amps are more practical than singular larger ones driving
TS > speakers would also apply.
TS > BTW, in case you don't understand A3 (common AM), full
TS > modulation requires audio power equal to half the power of
TS > the RF carrier.  There are some newer solid state analog
TS > and digital designs through the 100 KW level, though most
TS > higher power gear still uses tubes at least for finals.
TS > The traditional high level design uses an AB or B audio
TS > tube pair whose output modulates the B+ to one or two RF
TS > output tubes operated Class C.
Tubes are only OK for midrange from 100hz to the highest highs due to 
transformer saturation I've found in Cary, Counterpoint, Nikko, Conrad 
Johnson, Carver, CAT amplifiers all made from tubes.  They have no low end 
kick, but are loud because of their signifigantly lower damping factor, sort 
of like a receiver (damping of 20 to 100).  I however trust my Crown Macro 
3,600 watt amplifiers at damping of 1,000 at 10 hz to 400 hz into a 1 ohm per 
channel load, which i am not likely to run because whenever i happen to go 
beyond my 32 speaker cabinets (15"x2 in 16 cabinets, trapeziodal shape, and 
18"x2 in the other 16 cabinets, non trapeziodal) i always use more amplfiers. 
Currently the cheapest thing i can do is use 4 speakers per stereo amplifier, 
and all my subwoofers are 1,000 watts RMS being run at 2000 watts RMS with 
bridged amps (IHF damping factor is still > 300 at 20 hz to 400 hz, so no 
problem there with the slamming tight bass).  For the professional setups i 
do with my sound system, i would rather run 1 amp per speaker cabinet like i 
always do because i notice reactive EMF problems are affecting the clarity 
and the transience of the speakers in large setups.  Front loaded woofer 
systems are so old fashioned and inefficient (woofers mounted on the front 
panel of the speaker box, the old fashioned way, no pro setup uses these 
anymore to project sound over a crowd but are better suited for monitors).
Laszlo Sokolai
Team ANTI-Windows95/PRO-OS2/PRO-Unix
lsokolai@bbs42.com
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