Just a note,Think of ESR as how fast a capacitor will charge/discharge.
As Frank pointed out,think of slower caps acting more like rechargeable
batteries,that's too slow to filter out audio peaks,let alone RF.
At high current levels,wire resistance becomes an important factor,and
caps can help with the inherent voltage drop/sag.



Frank Gilliland wrote:

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 ----

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


-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

snip
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:

Oranges and apples...............
P.S. you are a idiot for even equating the two


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 for how long........."Do the math"

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.


One thing I am not surprised at........You will ignore the facts, like
you normally do to flame the group or express your pseudo
theory.


Yeah...Right, A few farads will make a justifiable difference. You're
to funny.

In , wrote:

snip
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:

Oranges and apples...............
P.S. you are a idiot for even equating the two

Then explain the operational difference between a power supply filter cap and a
cap placed across the input of a load. Duh....!!!

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 for how long........."Do the math"

......? I said it -CAN'T- provide more power than the power supply. Are you deaf?

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.


One thing I am not surprised at........You will ignore the facts, like
you normally do to flame the group or express your pseudo
theory.

Present some FACTS, Tnom. I dare you!



Yeah...Right, A few farads will make a justifiable difference. You're
to funny.

What's funny is watching you choke on basic DC power supply theory (pun
intended).







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

"...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 ----

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


-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Well here is some of the specs supplied for a 1 Farad cap from the
manufacture.,

# Capacitance 1 farad,+/- 5%, 20-24 Volt Surge, 105'C
# Dia. 3.54" x H 9.65"
# E.S.R. (0.0016 Ohm) Frequency? I don't care it works for me. Good enough
for me to use on a SSB amp with a 8 ' run of cable. Like I found out it just
helps
in reducing the voltage nulls during the audio peaks, and reduces the sudden
voltage drops in the electoral system. For
$59 bucks it OK to do. That's what he asked and This was my answer.


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

snip
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:

Oranges and apples...............
P.S. you are a idiot for even equating the two

Then explain the operational difference between a power supply filter cap
and a
cap placed across the input of a load. Duh....!!!

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 for how long........."Do the math"

.....? I said it -CAN'T- provide more power than the power supply. Are you
deaf?

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.


One thing I am not surprised at........You will ignore the facts, like
you normally do to flame the group or express your pseudo
theory.

Present some FACTS, Tnom. I dare you!



Yeah...Right, A few farads will make a justifiable difference. You're
to funny.

What's funny is watching you choke on basic DC power supply theory (pun
intended).







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

"...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 ----

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


-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Well here is some of the specs supplied for a 1 Farad cap from the
manufacture.,

# Capacitance 1 farad,+/- 5%, 20-24 Volt Surge, 105'C
# Dia. 3.54" x H 9.65"
# E.S.R. (0.0016 Ohm) Frequency? I don't care it works for me. Good enough
for me to use on a SSB amp with a 8 ' run of cable. Like I found out it just
helps
in reducing the voltage nulls during the audio peaks, and reduces the sudden
voltage drops in the electoral system. For
$59 bucks it OK to do. That's what he asked and This was my answer.


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

snip
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:

Oranges and apples...............
P.S. you are a idiot for even equating the two

Then explain the operational difference between a power supply filter cap
and a
cap placed across the input of a load. Duh....!!!

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 for how long........."Do the math"

.....? I said it -CAN'T- provide more power than the power supply. Are you
deaf?

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.


One thing I am not surprised at........You will ignore the facts, like
you normally do to flame the group or express your pseudo
theory.

Present some FACTS, Tnom. I dare you!



Yeah...Right, A few farads will make a justifiable difference. You're
to funny.

What's funny is watching you choke on basic DC power supply theory (pun
intended).







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

"...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 ----

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


-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Snipped because your response is just to ridiculous to
even bother reading. In a nutshell your dribble implies that:

A one farad cap used on a large amp (dx1600) used on
SSB will make a difference.. It can't make any noticeable
difference at all.

A one farad cap by definition can only supply one amp
for one second at a one volt potential. It can not make any real
difference on a setup that requires 150 amps on voice peaks.

The current draw on voice peaks last long enough to deplete
the benefits a one farad cap instantaneously. If the cap is depleted
instantaneously then a standard SSB voice keyup would instantaneously
absorb all of the caps ability to hold a voltage and make a noticeable
difference in a voice communication.

The problem is not in the theory but in the relative usefulness of
one farad for a 1500 watt amp. One farad is not big enough.