if your peaks are up that equates to higher (but probably not much like you
said) average output. BUT, you brought up a good point about the clipping

"Frank Gilliland" wrote in message
...
In , "Dr. Death"
wrote:

snip
So you agree, it would work for ssb

I agree that adding a cap across the power leads will help keep the peaks
up,
and that's assuming the amp isn't clipping on the peaks. IOW, it should
improve
the audio quality when using a less-than-perfect power supply, just as if
it
were an audio amp. What it -won't- do is improve your average output power
by
any significant margin.







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I have used the BIG caps as used on the audio amps on my RF power amp and
it did help on the current spikes that was needed on SSB peaks. Without the
Cap, the voltage could drop to 10.5 volts on current peaks measured at the
amp, now it might go to 12 - 12.5 volts only rising to the supplied 13.8
volts in the system.
It help to reduce the headlights flicker at night also.
Just type in FARAD in e-bay search under car stereo.
The caps can be dangerous when charged up . They can discharge VERY high
amps if shorted out as their ESR is very low. 1- 30 Farads can be found,
and
they are not cheap either. I have seen a bank of them even crank over a 8
cylinder engine. Try that with 100,00 uF Cap.





"Dr. Death" wrote in message
...
if your peaks are up that equates to higher (but probably not much like
you
said) average output. BUT, you brought up a good point about the clipping

"Frank Gilliland" wrote in message
...
In , "Dr. Death"
wrote:

snip
So you agree, it would work for ssb

I agree that adding a cap across the power leads will help keep the
peaks
up,
and that's assuming the amp isn't clipping on the peaks. IOW, it should
improve
the audio quality when using a less-than-perfect power supply, just as
if
it
were an audio amp. What it -won't- do is improve your average output
power
by
any significant margin.







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"Dr. Death",
Using a very large capacitor to keep the instantanious
voltage
from dropping very much certainly will work. The question is,
how
much benefit is going to be realized from that? The answer is,
not
very much. Now, balance that 'not very much' with the cost of
those
very large capacitors and draw your own conclusions.
Personally, I
think it's a waste of time, just isn't worth it. It usually
means
that you're trying to 'squeeze' more out of something than it
was
designed to do to start with, which is a kinda silly thing to
do. If
you want to try it, then have at it. I'd rather waste my money
on
other things...
'Doc

actually it was just food for thought, with all the flaming going on I
thought I would introduce a subject that would produce more thinking than
fighting.

"'Doc" wrote in message ...


"Dr. Death",
Using a very large capacitor to keep the instantanious
voltage
from dropping very much certainly will work. The question is,
how
much benefit is going to be realized from that? The answer is,
not
very much. Now, balance that 'not very much' with the cost of
those
very large capacitors and draw your own conclusions.
Personally, I
think it's a waste of time, just isn't worth it. It usually
means
that you're trying to 'squeeze' more out of something than it
was
designed to do to start with, which is a kinda silly thing to
do. If
you want to try it, then have at it. I'd rather waste my money
on
other things...
'Doc

"Dr. Death",
Good idea.
'Doc

I'll add to that those wonderful "Monster caps" that are those High farad
values of 5, 15, and 50 Farads (Thanks alot Alumapro, and Pheonix Gold) are
junk. Even if the measured or stated (ESR) is low. The other problem is ESL,
equivlent series inductance. The ESL is kind of like a the responsecurve of
a VSWR curver through the frequency rage of a Antenna.

The ESL changes with freq. Now that may be low with a DC circuit. But the
minute you start fluctuating that current and voltage, the ESL Will start to
rear it ugly head. Remember L = Inductace is the Opposition to current flow.

If you really want some good imput on this hit up Carsound.com Forums and
look up under Richard Clarks Archived topis for Capacitors.

"Frank Gilliland" wrote in message
...
In , "Dr. Death"
wrote:

I noticed that a lot of high end auto audio systems use a capacitor in
series with the main power lead to the amplifies so the amp hits harder.
Could this same principle be applied to ssb, I think it can.
place a 1 farad audio cap inline with the power lead to say a Texas star
dx1600 and you run the rig on ssb the cap will discharge under peak load
giving you a higher average output.

Any comments? (and I mean REAL comments)



Even though you are a troll, you actually raise a good point here. Now I'm
assuming you meant that the capacitor is connected in parallel with the
power
supply leads, because if it were connected in series you would get no
power.

In an SSB amp the RF power follows the audio, and will therefore have a
current
draw that varies at audio frequencies. A capacitor placed across the power
leads
of the amp, when combined with the inherent resistance of the wires from
the
battery, creates a simple low-pass filter which will help smooth out those
'audio' peaks. The bigger the amp, the bigger the cap. And keep the leads
from
the amp to the cap as short as possible.

BTW, this type of filter won't do much in AM service since the current
drawn by
the amp in AM is fairly steady (at least it -should- be, i.e, it's not
amplifying a signal loaded with overmodulation and 'swang'). But it -will-
filter out noise from the power supply.

A word about those 'moster caps' for audio amps: Most of them have a high
equivalent series resistance (ESR) which defeats the purpose of using
them. They
behave more like a rechargeable battery than a capacitor. Locate your
local
computer junkyard and get some of those big electrolytics from the
mainframe
power supplies. Typically, just one 100,000 uFd aluminum electrolytic has
a
lower ESR than a 1.0 farad 'monster' cap. Also remember that you can
reduce the
ESR by putting capacitors in parallel. Ten 10,000 uFd caps in parallel
will have
a much better ESR, and therefore much better filtering ability, than one
100,000
uFd capacitor of the same type, even though the total mFd value is the
same.





=============

"...but I admitted I was wrong, Like a man! Something you and QRM
have a problem with. You guys are wrong and you both know it and
are both too small to admit it."
---- Twistedhed ----

=============


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On Mon, 8 Dec 2003 03:23:00 -0600, "Dr. Death"
wrote:

I noticed that a lot of high end auto audio systems use a capacitor in
series with the main power lead to the amplifies so the amp hits harder.
Could this same principle be applied to ssb, I think it can.
place a 1 farad audio cap inline with the power lead to say a Texas star
dx1600 and you run the rig on ssb the cap will discharge under peak load
giving you a higher average output.

Any comments? (and I mean REAL comments)

A one farad capacitor can only supply one amp for one
second at one volt. Hardly worth the expense.

It can only prevent a voltage drop on the first few peaks
of a SSB modulated signal. It's usefulness would be almost
totally drained after speaking just one appropriate word, pointless.

In , wrote:

On Mon, 8 Dec 2003 03:23:00 -0600, "Dr. Death"
wrote:

I noticed that a lot of high end auto audio systems use a capacitor in
series with the main power lead to the amplifies so the amp hits harder.
Could this same principle be applied to ssb, I think it can.
place a 1 farad audio cap inline with the power lead to say a Texas star
dx1600 and you run the rig on ssb the cap will discharge under peak load
giving you a higher average output.

Any comments? (and I mean REAL comments)

A one farad capacitor can only supply one amp for one
second at one volt. Hardly worth the expense.

It can only prevent a voltage drop on the first few peaks
of a SSB modulated signal. It's usefulness would be almost
totally drained after speaking just one appropriate word, pointless.

Then there is not much point in using them in any kind of DC power supply, is
there? Of course there is. Do the math, Tnom:

A good car battery has, on the average, an source impedance of around 0.01 ohms
(dropping 1 volt per 100 amps, which is a darn good battery). Ten feet of #8 AWG
has a DC resistance of 0.0063 ohms, and we'll just assume that the negative lead
is grounded at 0 ohms. So the total source impedance at the input of the amp is
0.0163 ohms. Now take an amp that can do 500 watts PEP. Assuming 50% efficiency,
that means it can draw a maximum of 79.4 amps @ 12.6 volts. But since the source
impedance is 0.0163 ohms, the voltage is going to drop 1.3 volts on the peaks,
reducing the peak output by 50 watts or more. This is a type of soft-clipping
and can result in some significant AF -and- RF distortion. And that's not
considering the temperature coefficient of copper, which shows more resistance
as it warms up from carrying lots of current, making the situation worse.

Adding caps at the power input leads of the amp can significantly reduce the
source impedance of the power supply. It -can't- provide more power than the
supply is capable of providing, but it -can- smooth the voltage ripple just like
in any other type of power supply. And what if the vehicle is running? Do the
math: If you have a 100 amp alternator (at 13.8 volts), it has a source
impedance of .138 ohms, which is significantly higher than the battery, so it's
not going to be much help. In fact, because it's going to be so heavily loaded,
it's going to introduce some ripple into the power lines, ripple that can be
reduced by using caps at the input of the amp.

How much capacitance is needed? There is no easy equation. There are a number of
factors, such as the source resistance of the battery and alternator, resistance
of the wire, ESR of the capacitors, average modulation percentage, PEP watts,
etc, etc. Because of the very low impedance required by the amp, low ESR is
paramount. Despite the advertised claims, the 'monster' caps usually have an ESR
of several ohms, much higher than is usable. Computer-grade electrolytics have a
much lower ESR. Using many smaller caps in parallel is better than one big cap
because the ESR is much lower. Those are just a few things to consider. But the
general rule is to keep adding caps until they no longer make any improvement.


I'm really suprised, Tnom. After all the times you have shot your mouth off and
been proven wrong on technical topics, you -still- haven't learned to think
before you speak. Maybe next time.







=============

"...but I admitted I was wrong, Like a man! Something you and QRM
have a problem with. You guys are wrong and you both know it and
are both too small to admit it."
---- Twistedhed ----

=============


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Well lets see here DOC and Frank
Have you tried a Large farad cap on your amp? I thought not.
So unless you have then don't cut it.

Frank you need to learn what ESR is you ****en dum ass.
These cap have a very LOW ESR as I said in my first post I or do you not
read very well.
Doc , it works, and you know it could unless your a Dumass also. so why put
your little ****ty wisdom comments in
Sure its costs money, but to me running several alternators and a big amp
just to say Audio is a waste of money to me. We all have our quirks.
Why do CBERs spend good money just to raise the power out on a 4 watt rig to
7 watts and think its walking the dog, cant tell it on the receiving end.
O well beleave what you want. He asked a question and I gave a good answer,
it works.
Then here comes all the so called Brains on this group. Hell I dough if they
really do anything with there's, just sent on their ass and tell every one
else
how smart they think they really are .
SO called DOC is really a flunky, and Frank hell he must work for some
portal potty outfit.
Dam It would be nice if they could just give a answer without trying to act
as if they are the only ones in the world with knowledge.
**** them two.


Frank go and get one of those caps there are very LOW
"Frank Gilliland" wrote in message
news
In , wrote:

On Mon, 8 Dec 2003 03:23:00 -0600, "Dr. Death"
wrote:

I noticed that a lot of high end auto audio systems use a capacitor in
series with the main power lead to the amplifies so the amp hits harder.
Could this same principle be applied to ssb, I think it can.
place a 1 farad audio cap inline with the power lead to say a Texas star
dx1600 and you run the rig on ssb the cap will discharge under peak load
giving you a higher average output.

Any comments? (and I mean REAL comments)

A one farad capacitor can only supply one amp for one
second at one volt. Hardly worth the expense.

It can only prevent a voltage drop on the first few peaks
of a SSB modulated signal. It's usefulness would be almost
totally drained after speaking just one appropriate word, pointless.

Then there is not much point in using them in any kind of DC power supply,
is
there? Of course there is. Do the math, Tnom:

A good car battery has, on the average, an source impedance of around 0.01
ohms
(dropping 1 volt per 100 amps, which is a darn good battery). Ten feet of
#8 AWG
has a DC resistance of 0.0063 ohms, and we'll just assume that the
negative lead
is grounded at 0 ohms. So the total source impedance at the input of the
amp is
0.0163 ohms. Now take an amp that can do 500 watts PEP. Assuming 50%
efficiency,
that means it can draw a maximum of 79.4 amps @ 12.6 volts. But since the
source
impedance is 0.0163 ohms, the voltage is going to drop 1.3 volts on the
peaks,
reducing the peak output by 50 watts or more. This is a type of
soft-clipping
and can result in some significant AF -and- RF distortion. And that's not
considering the temperature coefficient of copper, which shows more
resistance
as it warms up from carrying lots of current, making the situation worse.

Adding caps at the power input leads of the amp can significantly reduce
the
source impedance of the power supply. It -can't- provide more power than
the
supply is capable of providing, but it -can- smooth the voltage ripple
just like
in any other type of power supply. And what if the vehicle is running? Do
the
math: If you have a 100 amp alternator (at 13.8 volts), it has a source
impedance of .138 ohms, which is significantly higher than the battery, so
it's
not going to be much help. In fact, because it's going to be so heavily
loaded,
it's going to introduce some ripple into the power lines, ripple that can
be
reduced by using caps at the input of the amp.

How much capacitance is needed? There is no easy equation. There are a
number of
factors, such as the source resistance of the battery and alternator,
resistance
of the wire, ESR of the capacitors, average modulation percentage, PEP
watts,
etc, etc. Because of the very low impedance required by the amp, low ESR
is
paramount. Despite the advertised claims, the 'monster' caps usually have
an ESR
of several ohms, much higher than is usable. Computer-grade electrolytics
have a
much lower ESR. Using many smaller caps in parallel is better than one big
cap
because the ESR is much lower. Those are just a few things to consider.
But the
general rule is to keep adding caps until they no longer make any
improvement.


I'm really suprised, Tnom. After all the times you have shot your mouth
off and
been proven wrong on technical topics, you -still- haven't learned to
think
before you speak. Maybe next time.







=============

"...but I admitted I was wrong, Like a man! Something you and QRM
have a problem with. You guys are wrong and you both know it and
are both too small to admit it."
---- Twistedhed ----

=============


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In 9McBb.1407$8y1.13274@attbi_s52, "MasterCBer" wrote:

Well lets see here DOC and Frank
Have you tried a Large farad cap on your amp?

I use caps on just about everything mobile. They work great to get the low-end
from an audio amp. No, I don't run an RF amp, base or mobile. Yes, I have
intalled a few; and yes, they do run better with a big cap on the power leads.
By 'better' I mean that the audio is cleaner and IMD is reduced.

I thought not.

No you didn't.

So unless you have then don't cut it.

Frank you need to learn what ESR is you ****en dum ass.
These cap have a very LOW ESR as I said in my first post I or do you not
read very well.

From Cornell Dubilier:

381LX473M016A452
47000 uFd @ 16 VDC
0.017 ohms @ 120 Hz
0.013 ohms @ 20 kHz

Now you can probably find farad-sized electrolytics -advertised- for lower ESR,
but they don't tell you the frequency or conditions under which that ESR was
measured. There are engineering standards for measuring such things as ESR.
Industry has to deal with these standards all the time. But as long as these
caps are not marketed for industrial use the manufacturers can declare an ESR
that is measured in any way they want, even by measuring the cap in a series
resonant circuit with a high impedance source. IOW, it's a lot of hype, just
like the ridiculous gain figures that are advertised for some CB antennas. About
the lowest -real- ESR you will find among those ultra-high-density caps is about
0.2 ohms, and it will cost you most of a paycheck (two or three paychecks if you
have a McJob).

The problem here is one that has existed since the first capacitor was invented:
There is a tradeoff between charge density (uF per cubic inch) and ESR. Whenever
the physical size of a capacitor gets too large, it usually dictates a different
type of capacitor. A 1 farad air capacitor would have an extremely low ESR, but
it would probably be as big as an aircraft carrier (which would introduce other
problems, but those are ignored for the sake of this example). If it was an
oil/paper capacitor it might be as big as a house. Even an aluminum electrolytic
of 1 farad would still be quite large for a mobile application. So these monster
caps are built with a different type of electrolytic process, one that packs
more farads into a smaller space, but at the expense of increased dielectric
absorption/hysteresis, i.e, a higher ESR.

Put more simply, if these big caps were as good as the advertisers claim them to
be, they would have replaced aluminum electrolytics a long, long time ago. They
haven't. Put even more simply, if it looks too good to be true, it probably is.
If you don't believe me, buy one and measure it yourself. You will need a very
low impedance source and load, then measure the difference in ripple voltage on
a scope. Post the results.

And just to make my point about smaller caps in parallel being better than one
big cap:

381LX472M016H012
4700 uFd @ 16 VDC
0.113 ohms @ 120 Hz
0.085 ohms @ 20 kHz

Put ten of the 4700 uFd caps in parallel and you have 47000 uFd, but with an ESR
of 0.0113 ohms @ 120 Hz and 0.0085 @ 20 kHz, which is better than the 47000 uFd
capacitor. This value would drop the source impedance (in my example from the
previous post) from 0.0163 ohms to 0.0067 ohms, meaning the voltage will only
drop 0.53 volts on a peak. So in this example, the caps give back three-quarters
of the power that is missing from the peaks when run without the caps. Compare
that to any size cap with an ESR of 0.2 ohms.






=============

"...but I admitted I was wrong, Like a man! Something you and QRM
have a problem with. You guys are wrong and you both know it and
are both too small to admit it."
---- Twistedhed ----

=============


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