Date: Sat, 26 Oct 2013 22:57:23 -0700
From: Grant Saviers <grants2@pacbell.net>
To: Jim Lux <jimlux@earthlink.net>, towertalk@contesting.com
Subject: Re: [TowerTalk] Tower and antenna decisions
Jim,
You're the audio expert, but didn't Bob Carver figure out some clever
variable supply voltage tricks with his big Sunfire amps? I have two
and my "Signature" stereo is rated 2 to 16 ohms (1250w/ch 4 ohms) and
runs stone cold even when delivering big power. No other amp I've tried
had the headroom needed for my B&W 801Fs to generate max orchestral
peaks at concert hall levels.
So isn't what you are suggesting been done before in the audio domain?
Grant KZ1W
## whoa.... lets not even go there.....comparing high power audio amps with
RF amps.
All the big SS audio amps I have seen use fixed voltage..and most use an
unregulated
supply, with huge C filter caps...and a huge torroid. Typ is like 67-90 vdc.
## The output Z on most of the bigger SS audio amps is just a fraction of an
ohm at best,
like .1 or .2 ohm. Now you can see why they put out only XXX watts into 10
ohms, and
a bunch more into 8 ohms....and still more into 4 ohms..and insane amounts of
power into 2 ohms.
## You get get max power transfer with matched Zs. Into a low 2 or 4 ohm
load, it will not only
put out globs of power.... it will also put out one helluva lot of current as
well.
## On my Denon amp, when operating with low power, it slides into class A
mode. The bias is always
sliding.. depending on drive level. Any more than aprx 10 watts, and it
slides into class B mode...then off we
go up to 400++ into 2 ohms. Krell does a similar thing with their Class A
amps to keep em from burning up.
If the wife is home, I can never crank it up anyway...so gave up years ago, and
got relegated to headphones...
.which I have gone through 12-13 pairs over the years. The Sennheiser HD-650s
is what I now use....driven
by a 4 x channel rack mount Class A headphone amp. IE: 4 x stereo
headphones, all independent can be
used at one time..each with their own controls Plan B is the Sirius / XM
satellite radio in the mustang, + 6 x CD
disc player + kw amp......provided the wife is not in the car.
Jim VE7RF
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