Hi all,

I installed a 10" sub w/box and a 300 watt bridged amp last night in my car.
I'm having problems with the amplifier cutting out and going into overload
protection. It does this for 2 or 3 seconds, then kicks in again. The louder
I turn up the volume, the worse it gets.

They are both cheap quality, (Don't laugh, the sub is a Thump!, cant
remember the name of the amp) but I have heard them before, and they worked
better than this.

I think the problem lies in the power wiring for the amp, but maybe one of
you guys could verify for me. The amp came with its own wiring kit,
advertised as 10 gauge, and it looks like 10 gauge. However, if you strip
the wires back, its actually 14 gauge (false advertising if you ask me). So,
my amp has a 16 foot 14 gauge wire powering it.

Anyway, this was the only wire I had so I installed it, directly to the
battery, and I'm wondering if this small wire just cant produce the juice
for this amp to push out the power? It runs cool, so its not like the amp is
getting hot.

Am I on the right track? Is this 14 gauge wire a bottleneck? I'm thinking of
trying a booster cable after work to see if it makes an improvement.

Ryan.

Ryan,

I would say that you may have a bit of a bottleneck with 14 gauge power
wire, but I don't believe this is was is causing your problem.

1.] Check the power and ground connections for loose fits. Make sure the
ground wire is secured to bare metal and is not loose.
2.] Make sure the mounting of the amp is also secure. It may not me a good
idea to have the amp mounted to (or touching) bare metal.
3.] Check your wire connections to the sub and make sure the positive and
negative wires are not touching (and cannot touch).

I guess all my guesses point to a short in the system somewhere. Otherwise,
you may have a faulty amp (sorry).

--

--------------------------------------------------------------
Onyi C. Ejiasa
BlaQmail.com - Empower your e-mail.
--------------------------------------------------------------
Vote for my install @ sounddomain.com!
http://www.sounddomain.com/id/blaqaltima
--------------------------------------------------------------

"Ryan Lester" wrote in message
news:saIBb.17777$f7.842262@localhost...
Hi all,

I installed a 10" sub w/box and a 300 watt bridged amp last night in my
car.
I'm having problems with the amplifier cutting out and going into overload
protection. It does this for 2 or 3 seconds, then kicks in again. The
louder
I turn up the volume, the worse it gets.

They are both cheap quality, (Don't laugh, the sub is a Thump!, cant
remember the name of the amp) but I have heard them before, and they
worked
better than this.

I think the problem lies in the power wiring for the amp, but maybe one of
you guys could verify for me. The amp came with its own wiring kit,
advertised as 10 gauge, and it looks like 10 gauge. However, if you strip
the wires back, its actually 14 gauge (false advertising if you ask me).
So,
my amp has a 16 foot 14 gauge wire powering it.

Anyway, this was the only wire I had so I installed it, directly to the
battery, and I'm wondering if this small wire just cant produce the juice
for this amp to push out the power? It runs cool, so its not like the amp
is
getting hot.

Am I on the right track? Is this 14 gauge wire a bottleneck? I'm thinking
of
trying a booster cable after work to see if it makes an improvement.

Ryan.

I'll bet you have a dual voice 4 ohm coil sub wired in parallel to the amp
and THAT'S what doing it.



Paul Vina



"Ryan Lester" wrote in message
news:saIBb.17777$f7.842262@localhost...
Hi all,

I installed a 10" sub w/box and a 300 watt bridged amp last night in my
car.
I'm having problems with the amplifier cutting out and going into overload
protection. It does this for 2 or 3 seconds, then kicks in again. The
louder
I turn up the volume, the worse it gets.

They are both cheap quality, (Don't laugh, the sub is a Thump!, cant
remember the name of the amp) but I have heard them before, and they
worked
better than this.

I think the problem lies in the power wiring for the amp, but maybe one of
you guys could verify for me. The amp came with its own wiring kit,
advertised as 10 gauge, and it looks like 10 gauge. However, if you strip
the wires back, its actually 14 gauge (false advertising if you ask me).
So,
my amp has a 16 foot 14 gauge wire powering it.

Anyway, this was the only wire I had so I installed it, directly to the
battery, and I'm wondering if this small wire just cant produce the juice
for this amp to push out the power? It runs cool, so its not like the amp
is
getting hot.

Am I on the right track? Is this 14 gauge wire a bottleneck? I'm thinking
of
trying a booster cable after work to see if it makes an improvement.

Ryan.

Ryan Lester wrote:
Hi all,

I installed a 10" sub w/box and a 300 watt bridged amp last night in my car.
I'm having problems with the amplifier cutting out and going into overload
protection. It does this for 2 or 3 seconds, then kicks in again. The louder
I turn up the volume, the worse it gets.

They are both cheap quality, (Don't laugh, the sub is a Thump!, cant
remember the name of the amp) but I have heard them before, and they worked
better than this.

My first sub was a "Thump!". I figured they'd been out of business for
years!


I think the problem lies in the power wiring for the amp, but maybe one of
you guys could verify for me. The amp came with its own wiring kit,
advertised as 10 gauge, and it looks like 10 gauge. However, if you strip
the wires back, its actually 14 gauge (false advertising if you ask me). So,
my amp has a 16 foot 14 gauge wire powering it.


Am I on the right track? Is this 14 gauge wire a bottleneck? I'm thinking of
trying a booster cable after work to see if it makes an improvement.

Even that puny wire should carry enough current to your amp for it to
run. It's just that using too small of a gauge of wire may result in the
wire overheating, and setting something on fire. (I say "may", but in
your case - a 300 watt amp sucking juice through 16 feet of 14 gauge
wire - it's amazing your **** hasn't burned down already). It's more
likely the source of your problem is a bad connection - usually a
ground. Make sure that when you ground your amplifiers, it's to a clean,
paint free section of sheet metal on teh cars floorpan, and that it is
secured tightly by a screw or bolt. Make sure you don't drill through a
brake line or something - look under the car before making your ground
point. And make sure you replace that 14 gauge crap with a 10 or 8 gauge
power cable, and make sure it's fused. A proper amp kit is $20 at
Wal-Mart. A proper installation is $30 at your average car audio shop.
Having your g-ride not go up in flames because of shoddy shade-tree
jerry-rigged installs: priceless.

--
Lizard

Hey guys,

Thanks for your suggestions, but as it turns out, it was definitely the
wire. I bought a real 10 gauge wire set yesterday, and installed it last
night. It totally rocks now. What a difference it made, I can't believe it.
That 14 guage wire was like pushing a river through a garden hose.

The amazing thing was, the old small 14 gauge wire wasn't getting hot.
Weird.

Thanks.

Ryan.




"Ryan Lester" wrote in message
news:saIBb.17777$f7.842262@localhost...
Hi all,

I installed a 10" sub w/box and a 300 watt bridged amp last night in my
car.
I'm having problems with the amplifier cutting out and going into overload
protection. It does this for 2 or 3 seconds, then kicks in again. The
louder
I turn up the volume, the worse it gets.

They are both cheap quality, (Don't laugh, the sub is a Thump!, cant
remember the name of the amp) but I have heard them before, and they
worked
better than this.

I think the problem lies in the power wiring for the amp, but maybe one of
you guys could verify for me. The amp came with its own wiring kit,
advertised as 10 gauge, and it looks like 10 gauge. However, if you strip
the wires back, its actually 14 gauge (false advertising if you ask me).
So,
my amp has a 16 foot 14 gauge wire powering it.

Anyway, this was the only wire I had so I installed it, directly to the
battery, and I'm wondering if this small wire just cant produce the juice
for this amp to push out the power? It runs cool, so its not like the amp
is
getting hot.

Am I on the right track? Is this 14 gauge wire a bottleneck? I'm thinking
of
trying a booster cable after work to see if it makes an improvement.

Ryan.

"Ryan Lester" wrote in message
news:c51Cb.17942$f7.847641@localhost...
| Hey guys,
|
| Thanks for your suggestions, but as it turns out, it was definitely the
| wire. I bought a real 10 gauge wire set yesterday, and installed it last
| night. It totally rocks now. What a difference it made, I can't believe
it.
| That 14 guage wire was like pushing a river through a garden hose.
|
| The amazing thing was, the old small 14 gauge wire wasn't getting hot.
| Weird.
|

Doesn't sound weird - sounds like a connection problem - or it could have
been an operating voltage problem, depending upon what the Vdrop/ft was on
the 14ga (although I seriously doubt it).

Thanks for your suggestions, but as it turns out, it was definitely the
wire. I bought a real 10 gauge wire set yesterday, and installed it last
night. It totally rocks now. What a difference it made, I can't believe
it.
That 14 guage wire was like pushing a river through a garden hose.

The amazing thing was, the old small 14 gauge wire wasn't getting hot.
Weird.

That's probably because it was a connection problem. I sincerely doubt it
was wire gauge that was the issue. That's very rare.

well assuming 100% effiency 300 watts divided by 12 volts is only 25 amps.
getting towards the high end of 14 gauge wire.. but not way out there..
think, wireing in your more to alot of wall outlets is 14 gauge and they are
on 20amp breakers...
I really think it was a bad connection myself.. and it was breaking down b/c
of vibration or maybe even heat..

Adair

well assuming 100% effiency 300 watts divided by 12 volts is only 25 amps.
getting towards the high end of 14 gauge wire.. but not way out there..
think, wireing in your more to alot of wall outlets is 14 gauge and they are
on 20amp breakers...

But at 120Volts, not 12. Big difference.

Les

"Soundfreak03" wrote in message
...
well assuming 100% effiency 300 watts divided by 12 volts is only 25
amps.
getting towards the high end of 14 gauge wire.. but not way out there..
think, wireing in your more to alot of wall outlets is 14 gauge and they
are
on 20amp breakers...

But at 120Volts, not 12. Big difference.

Les

Yes, and also AC, but current is current..
Adair

It was NOT a connection problem.

The ground was on shiny bare metal that I had cleaned with a wire brush on
my drill prior to bolting down the wire. I used one of the rear strut nuts
for ground, and removed the surrounding paint with the wire wheel.

I also cleaned the positive terminal at the battery with baking soda/water,
and then with the wire brush on the drill to make it nice and shiny. To
boot, I connected the new wires in the exact same places, in the same
manner. So, there was no difference the quality of the connections between
the 14 and 10 gauge wire.

Ryan.



"Mark Zarella" wrote in message
...
Thanks for your suggestions, but as it turns out, it was definitely the
wire. I bought a real 10 gauge wire set yesterday, and installed it last
night. It totally rocks now. What a difference it made, I can't believe
it.
That 14 guage wire was like pushing a river through a garden hose.

The amazing thing was, the old small 14 gauge wire wasn't getting hot.
Weird.

That's probably because it was a connection problem. I sincerely doubt it
was wire gauge that was the issue. That's very rare.

Old wire could have had a small break in it or something. Quite common,
actually.

But it's physically impossible for there to be such a dramatic resistance
difference between 14 and 10 gauge for the type of lengths that we're
discussing. Both are well under an ohm, and as such, even if you were
drawing 50 amps through the thing, the difference in voltage drop would be
negligible compared to the absolute voltage drop. Without doing the
calculations, I'd guess it would be on the order of 5% of the absolute v
drop.

If there was a break or bad connection, however, the difference in
resistance could be something like 1000 times more rather than just ~2.

"Ryan Lester" wrote in message
news:g2mCb.223$Ur.8961@localhost...
It was NOT a connection problem.

The ground was on shiny bare metal that I had cleaned with a wire brush on
my drill prior to bolting down the wire. I used one of the rear strut nuts
for ground, and removed the surrounding paint with the wire wheel.

I also cleaned the positive terminal at the battery with baking
soda/water,
and then with the wire brush on the drill to make it nice and shiny. To
boot, I connected the new wires in the exact same places, in the same
manner. So, there was no difference the quality of the connections between
the 14 and 10 gauge wire.

Ryan.



"Mark Zarella" wrote in message
...
Thanks for your suggestions, but as it turns out, it was definitely
the
wire. I bought a real 10 gauge wire set yesterday, and installed it
last
night. It totally rocks now. What a difference it made, I can't
believe
it.
That 14 guage wire was like pushing a river through a garden hose.

The amazing thing was, the old small 14 gauge wire wasn't getting hot.
Weird.

That's probably because it was a connection problem. I sincerely doubt
it
was wire gauge that was the issue. That's very rare.

Yes, and also AC, but current is current..
Adair



Right current is current. But to achieve equal Wattage numbers between 12V and
120V the amperage must increase signifigantly.
BTW 14 gauge is against code, must be 12 for a 20 amp breaker and 10 for a
30amp breaker. I have not seen 14 in houses in a long time, and that was old
aluminum wire. You can get away with 14 if it is daisy chaining things like
light fixtures where it will not see alot of current.

Les

"Soundfreak03" wrote in message
...
Yes, and also AC, but current is current..
Adair



Right current is current. But to achieve equal Wattage numbers between 12V
and
120V the amperage must increase signifigantly.
BTW 14 gauge is against code, must be 12 for a 20 amp breaker and 10 for a
30amp breaker. I have not seen 14 in houses in a long time, and that was
old
aluminum wire. You can get away with 14 if it is daisy chaining things
like
light fixtures where it will not see alot of current.

Les

Les, I think his point was that the voltage doesn't matter. Just the
current.

The reason for this (among others) is because the power dissipated by the
wire is I^2*Rw, where Rw is the resistance of the wire. The voltage drop
*across the wire* will be the same in the 12v case and 120v case if the
current is the same.

Les, I think his point was that the voltage doesn't matter. Just the
current.

Right. I was just wanting to clarify though that even with the same current the
power would be signifiganty different.

The reason for this (among others) is because the power dissipated by the
wire is I^2*Rw, where Rw is the resistance of the wire. The voltage drop
*across the wire* will be the same in the 12v case and 120v case if the
current is the same.

Right, but I was making the point that just because you can use 14 gauge wire
in your house doesnt mean it is suitable for your cars power wire, more of a
clarification point. And I agree with you that the voltage drop between the 10
and 14 wouldnt have made that signifigant a difference. Sorry if my posting was
not clear.

Les

Les, I think his point was that the voltage doesn't matter. Just the
current.

Right. I was just wanting to clarify though that even with the same
current the
power would be signifiganty different.

But it's not. The power dissipated by the wire is identical in each case.
That's the power we're interested in because that's what causes the wire to
heat up.

two things:

one, using suspension or other stressed mounting points as an amp ground
isn't the best idea in the world. They can move if they are under stress
which could create a poor ground over time, but more importantly your
grounding ring terminal isn't hardened to anywhere near the same grade
as either the fastener or the car body - you greatly increase the
chances of that bolted junction working loose as the vehicle works
against that soft terminal material. That's why I would personally never
use a seat belt attachment point, ot the strut junction you used.

two, what did you do to improve the connectivity at the car battery
negative side? None of the rest of this stuff is going to help if you
have a poor ground path.

JD

Ryan Lester wrote:

It was NOT a connection problem.

The ground was on shiny bare metal that I had cleaned with a wire brush on
my drill prior to bolting down the wire. I used one of the rear strut nuts
for ground, and removed the surrounding paint with the wire wheel.

I also cleaned the positive terminal at the battery with baking soda/water,
and then with the wire brush on the drill to make it nice and shiny. To
boot, I connected the new wires in the exact same places, in the same
manner. So, there was no difference the quality of the connections between
the 14 and 10 gauge wire.

Ryan.



"Mark Zarella" wrote in message
...


Thanks for your suggestions, but as it turns out, it was definitely the
wire. I bought a real 10 gauge wire set yesterday, and installed it last
night. It totally rocks now. What a difference it made, I can't believe


it.


That 14 guage wire was like pushing a river through a garden hose.

The amazing thing was, the old small 14 gauge wire wasn't getting hot.
Weird.


That's probably because it was a connection problem. I sincerely doubt it
was wire gauge that was the issue. That's very rare.

Right. I was just wanting to clarify though that even with the same
current the
power would be signifiganty different.

But it's not. The power dissipated by the wire is identical in each case.
That's the power we're interested in because that's what causes the wire to
heat up.

I realized that I must not be making myself clear. I understand the power
dissipated is the same, but the loads (amp) ability to safely draw power,
watts, is different.

20 amps at 120 volts will allow the amp to produce 2400 watts. But 20 amps at
12 volts is only 240 watts. Of course assuming 100% effenciency and no voltage
drop etc.

Thats all I was trying to clarify. Hopefully I am making more sense

Les

Good point about the hardness of the ring terminal, I'll keep an eye on that. Not too worried about it at the moment, but its easy to check it.

I didn't change the manner of connectivity at the battery side whatsoever, I used the same type of ring connector with both wires. I was using 14ga for both pos. and neg. before, now they are both 10ga.

I know you guys dont' believe me, or think I'm missing something here, but I challenge anyone using a ~300watt amp driving a 10" or larger sub to switch from the 8 or 10 ga that your using for power now and go to a 14ga (18 feet of it) and tell me if it works the same.

Ryan.


"John Durbin" wrote in message ...
two things:

one, using suspension or other stressed mounting points as an amp ground isn't the best idea in the world. They can move if they are under stress which could create a poor ground over time, but more importantly your grounding ring terminal isn't hardened to anywhere near the same grade as either the fastener or the car body - you greatly increase the chances of that bolted junction working loose as the vehicle works against that soft terminal material. That's why I would personally never use a seat belt attachment point, ot the strut junction you used.

two, what did you do to improve the connectivity at the car battery negative side? None of the rest of this stuff is going to help if you have a poor ground path.

JD

Ryan Lester wrote:

It was NOT a connection problem.

The ground was on shiny bare metal that I had cleaned with a wire brush on
my drill prior to bolting down the wire. I used one of the rear strut nuts
for ground, and removed the surrounding paint with the wire wheel.

I also cleaned the positive terminal at the battery with baking soda/water,
and then with the wire brush on the drill to make it nice and shiny. To
boot, I connected the new wires in the exact same places, in the same
manner. So, there was no difference the quality of the connections between
the 14 and 10 gauge wire.

Ryan.



"Mark Zarella" wrote in message
...
Thanks for your suggestions, but as it turns out, it was definitely the
wire. I bought a real 10 gauge wire set yesterday, and installed it last
night. It totally rocks now. What a difference it made, I can't believe
it.
That 14 guage wire was like pushing a river through a garden hose.

The amazing thing was, the old small 14 gauge wire wasn't getting hot.
Weird.
That's probably because it was a connection problem. I sincerely doubt it
was wire gauge that was the issue. That's very rare.

Been there, done that, it does.

"Ryan Lester" wrote in message
news:LClDb.832$Ur.33216@localhost...
Good point about the hardness of the ring terminal, I'll keep an eye on
that. Not too worried about it at the moment, but its easy to check it.

I didn't change the manner of connectivity at the battery side whatsoever, I
used the same type of ring connector with both wires. I was using 14ga for
both pos. and neg. before, now they are both 10ga.

I know you guys dont' believe me, or think I'm missing something here, but I
challenge anyone using a ~300watt amp driving a 10" or larger sub to switch
from the 8 or 10 ga that your using for power now and go to a 14ga (18 feet
of it) and tell me if it works the same.

Ryan.


"John Durbin" wrote in message
...
two things:

one, using suspension or other stressed mounting points as an amp ground
isn't the best idea in the world. They can move if they are under stress
which could create a poor ground over time, but more importantly your
grounding ring terminal isn't hardened to anywhere near the same grade as
either the fastener or the car body - you greatly increase the chances of
that bolted junction working loose as the vehicle works against that soft
terminal material. That's why I would personally never use a seat belt
attachment point, ot the strut junction you used.

two, what did you do to improve the connectivity at the car battery
negative side? None of the rest of this stuff is going to help if you have a
poor ground path.

JD

Ryan Lester wrote:

It was NOT a connection problem.

The ground was on shiny bare metal that I had cleaned with a wire brush on
my drill prior to bolting down the wire. I used one of the rear strut nuts
for ground, and removed the surrounding paint with the wire wheel.

I also cleaned the positive terminal at the battery with baking soda/water,
and then with the wire brush on the drill to make it nice and shiny. To
boot, I connected the new wires in the exact same places, in the same
manner. So, there was no difference the quality of the connections between
the 14 and 10 gauge wire.

Ryan.



"Mark Zarella" wrote in message
...
Thanks for your suggestions, but as it turns out, it was definitely the
wire. I bought a real 10 gauge wire set yesterday, and installed it last
night. It totally rocks now. What a difference it made, I can't believe
it.
That 14 guage wire was like pushing a river through a garden hose.

The amazing thing was, the old small 14 gauge wire wasn't getting hot.
Weird.
That's probably because it was a connection problem. I sincerely
doubt it
was wire gauge that was the issue. That's very rare.

If you calculate the math relative to voltage drop over that length of
cable, it's definitely noticeable. Depends a little bit on whether your
amp is regulated or not, the loss of wattage is more likely to be
noticed in that scenario with a loosely regulated amp than a fully
regulated one. The offse tis the regulated amp puts more current load on
the cable as it tries to offset the voltage drop. Either way, you're
better off using an adequate gauge of cable.

About the negative side, did you run your amp negative to the battery?
Or just to the car chassis? The latter is better, but it's a good idea
to add a reinforcing cable to the ground path at the battery too,
otherwise you may still see voltage drop across that junction.

JD

Ryan Lester wrote:

Good point about the hardness of the ring terminal, I'll keep an eye
on that. Not too worried about it at the moment, but its easy to check
it.

I didn't change the manner of connectivity at the battery side
whatsoever, I used the same type of ring connector with both wires. I
was using 14ga for both pos. and neg. before, now they are both 10ga.

I know you guys dont' believe me, or think I'm missing something here,
but I challenge anyone using a ~300watt amp driving a 10" or larger
sub to switch from the 8 or 10 ga that your using for power now and go
to a 14ga (18 feet of it) and tell me if it works the same.

Ryan.



"John Durbin"
wrote in message ...
two things:

one, using suspension or other stressed mounting points as an amp
ground isn't the best idea in the world. They can move if they are
under stress which could create a poor ground over time, but more
importantly your grounding ring terminal isn't hardened to
anywhere near the same grade as either the fastener or the car
body - you greatly increase the chances of that bolted junction
working loose as the vehicle works against that soft terminal
material. That's why I would personally never use a seat belt
attachment point, ot the strut junction you used.

two, what did you do to improve the connectivity at the car
battery negative side? None of the rest of this stuff is going to
help if you have a poor ground path.

JD

Ryan Lester wrote:

It was NOT a connection problem.

The ground was on shiny bare metal that I had cleaned with a wire brush on
my drill prior to bolting down the wire. I used one of the rear strut nuts
for ground, and removed the surrounding paint with the wire wheel.

I also cleaned the positive terminal at the battery with baking soda/water,
and then with the wire brush on the drill to make it nice and shiny. To
boot, I connected the new wires in the exact same places, in the same
manner. So, there was no difference the quality of the connections between
the 14 and 10 gauge wire.

Ryan.



"Mark Zarella" wrote in message
...


Thanks for your suggestions, but as it turns out, it was definitely the
wire. I bought a real 10 gauge wire set yesterday, and installed it last
night. It totally rocks now. What a difference it made, I can't believe


it.


That 14 guage wire was like pushing a river through a garden hose.

The amazing thing was, the old small 14 gauge wire wasn't getting hot.
Weird.


That's probably because it was a connection problem. I sincerely doubt it
was wire gauge that was the issue. That's very rare.

If you calculate the math relative to voltage drop over that length of
cable, it's definitely noticeable.

Depends on what you mean by "noticeable". What are you noticing with? Your
ears when listening to the audio system? Or your eyes when looking at the
voltmeter?

all of the above, my quibbling friend :-)

JD

Mark Zarella wrote:

If you calculate the math relative to voltage drop over that length of
cable, it's definitely noticeable.



Depends on what you mean by "noticeable". What are you noticing with? Your
ears when listening to the audio system? Or your eyes when looking at the
voltmeter?

I'll have to part ways with you on the sound part. Can't say I've ever
noticed, and the math doesn't support that notion either.

"John Durbin" wrote in message
...
all of the above, my quibbling friend :-)

JD

Mark Zarella wrote:

If you calculate the math relative to voltage drop over that length of
cable, it's definitely noticeable.



Depends on what you mean by "noticeable". What are you noticing with?
Your
ears when listening to the audio system? Or your eyes when looking at
the
voltmeter?

Excuse me? The math supports loss of power calculations very nicely ...
and so will SQ listening, provided the system wasn't overpowered to
begin with. Have you lost the ability to hear clipping?

JD

Mark Zarella wrote:

I'll have to part ways with you on the sound part. Can't say I've ever
noticed, and the math doesn't support that notion either.

"John Durbin" wrote in message
...


all of the above, my quibbling friend :-)

JD

Mark Zarella wrote:



If you calculate the math relative to voltage drop over that length of
cable, it's definitely noticeable.




Depends on what you mean by "noticeable". What are you noticing with?


Your


ears when listening to the audio system? Or your eyes when looking at


the


voltmeter?

Excuse me? The math supports loss of power calculations very nicely ...
and so will SQ listening, provided the system wasn't overpowered to
begin with. Have you lost the ability to hear clipping?

The math supports the loss of power. But the loss of power associated with
going from 8-10 to 14 gauge does not exceed "accepted" psychophysical
thresholds. Especially when you factor in the nonlinearities such as
amplifier output Z, loudspeaker power compression, power supply regulation,
and electrical system output Z.

I jumped in mid-stream - what length of cable run are we talking about,
and what size amplifier?

JD

Mark Zarella wrote:

Excuse me? The math supports loss of power calculations very nicely ...
and so will SQ listening, provided the system wasn't overpowered to
begin with. Have you lost the ability to hear clipping?



The math supports the loss of power. But the loss of power associated with
going from 8-10 to 14 gauge does not exceed "accepted" psychophysical
thresholds. Especially when you factor in the nonlinearities such as
amplifier output Z, loudspeaker power compression, power supply regulation,
and electrical system output Z.

18 ft. "300 watts".

"John Durbin" wrote in message
...
I jumped in mid-stream - what length of cable run are we talking about,
and what size amplifier?

JD

Mark Zarella wrote:

Excuse me? The math supports loss of power calculations very nicely ...
and so will SQ listening, provided the system wasn't overpowered to
begin with. Have you lost the ability to hear clipping?



The math supports the loss of power. But the loss of power associated
with
going from 8-10 to 14 gauge does not exceed "accepted" psychophysical
thresholds. Especially when you factor in the nonlinearities such as
amplifier output Z, loudspeaker power compression, power supply
regulation,
and electrical system output Z.

hmmm ... I make that to be something like 75 watts loss.

(300/.6) = 500 input watts, divided by 13V = 38.5A of input current.

14 AWG stranded is about 2.5 ohm loss per 1000 ft, so 0.045 ohm over 18
feet. Personally, I think that's less resistance than you'd measure if
you took an average piece of 14 AWG cable you found in an install and
measured it end to end with a good, zero'd meter but it is what the
charts say, so let's use it.

For voltage drop, E=IR, or 38.5*0.045 = 1.73 volt drop.

For power differences in a loosely regulated amp, V1^2/V2^2 or
13^2/11.27^2 = 1.33, or a 33% drop in power. For a 300 watt amp (I
assumed for purposes of this argument that the amp was 300 W @ 13V input
throughout) that would come up to 225.6 watts lost.

Converting that to dB, I would tend to agree that you are skirting the
limits of audibility, however having spent several years driving two
different vehicles with roughly 300 watt systems using loosely regulated
amps, I also can say that the voltage drop is audible - not constantly,
but certainly when pushing the system close to the onset of clipping
which I found happened quite often with that relatively small amount of
power. And not because I had used 14 AWG, one truck had a 10AWG cable
and the other 8 AWG. But the voltage drop at idle was about 2V, and I
could tell the difference.

JD

Mark Zarella wrote:

18 ft. "300 watts".

"John Durbin" wrote in message
...


I jumped in mid-stream - what length of cable run are we talking about,
and what size amplifier?

JD

Mark Zarella wrote:



Excuse me? The math supports loss of power calculations very nicely ...
and so will SQ listening, provided the system wasn't overpowered to
begin with. Have you lost the ability to hear clipping?




The math supports the loss of power. But the loss of power associated


with


going from 8-10 to 14 gauge does not exceed "accepted" psychophysical
thresholds. Especially when you factor in the nonlinearities such as
amplifier output Z, loudspeaker power compression, power supply


regulation,


and electrical system output Z.

hmmm ... I make that to be something like 75 watts loss.

(300/.6) = 500 input watts, divided by 13V = 38.5A of input current.

14 AWG stranded is about 2.5 ohm loss per 1000 ft, so 0.045 ohm over 18
feet. Personally, I think that's less resistance than you'd measure if
you took an average piece of 14 AWG cable you found in an install and
measured it end to end with a good, zero'd meter but it is what the
charts say, so let's use it.

Any imperfections would also be present in the other wire.

For voltage drop, E=IR, or 38.5*0.045 = 1.73 volt drop.

For power differences in a loosely regulated amp, V1^2/V2^2 or
13^2/11.27^2 = 1.33, or a 33% drop in power. For a 300 watt amp (I
assumed for purposes of this argument that the amp was 300 W @ 13V input
throughout) that would come up to 225.6 watts lost.

Converting that to dB, I would tend to agree that you are skirting the
limits of audibility, however having spent several years driving two
different vehicles with roughly 300 watt systems using loosely regulated
amps, I also can say that the voltage drop is audible - not constantly,
but certainly when pushing the system close to the onset of clipping
which I found happened quite often with that relatively small amount of
power. And not because I had used 14 AWG, one truck had a 10AWG cable
and the other 8 AWG. But the voltage drop at idle was about 2V, and I
could tell the difference.

I'm guessing there was another variable at play there because I just don't
see how the calculated value would account for it. I also performed the
same calculations, and I got 286w vs 253w, but I assumed 12v supply voltage.
Assuming 13v is probably more realistic. My number yields a 0.5dB
difference. Yours would probably be closer to 0.6? Anyway, as I mentioned
in my other post, factoring in amplifier output impedance, loudspeaker power
compression, power supply regulation,and electrical system output impedance
is going to decrease that difference rather substantially.