I have an Xtant A4004. It's in three channel mode, the components work
fine, but if the sub hits, the amp puts out no sound on the hit. Basically
it makes a noise for about .1 seconds and then silence for about 2 seconds,
then it repeats. My installer said it was a bad amp, so I replaced it, the
new amp does the same thing. Then I was told it was the alternator, so
brilliant me.... I replaced the alternator (granted I wanted a polished one
anyway and it was an excuse). Same behavior. I'm now wondering if its the
battery because I left the music running at a normal listening level with
the car off (obviously without the sub hooked up) and the battery died after
about 20 minutes. However I THOUGHT I'd be able to test the battery by
jumping it to another car. I hooked up the sub again but had the same
behavior. So, is this a valid battery test, or if not, why? Next step is
to pull the battery out of my wifes car and hook that up and see what
happens, but I was hoping to avoid having to do that with a pair of jumper
cables.

I have an Xtant A4004. It's in three channel mode, the components work
fine, but if the sub hits, the amp puts out no sound on the hit.
Basically
it makes a noise for about .1 seconds and then silence for about 2
seconds,
then it repeats. My installer said it was a bad amp, so I replaced it,
the
new amp does the same thing. Then I was told it was the alternator, so
brilliant me.... I replaced the alternator (granted I wanted a polished
one
anyway and it was an excuse). Same behavior. I'm now wondering if its
the
battery because I left the music running at a normal listening level with
the car off (obviously without the sub hooked up) and the battery died
after
about 20 minutes. However I THOUGHT I'd be able to test the battery by
jumping it to another car. I hooked up the sub again but had the same
behavior. So, is this a valid battery test, or if not, why? Next step is
to pull the battery out of my wifes car and hook that up and see what
happens, but I was hoping to avoid having to do that with a pair of jumper
cables.

That actually sounds like a classic symptom of a bad battery to me.
Contrary to what many people in here claim, the battery plays an active role
in powering the audio system. Anyone who has ever disconnected the battery
while the car is running (not recommended if you value your car!) will see
the exact symptoms you're describing when trying to run their audio system.
The amp is essentially shutting off and turning back on everytime the
current draw is substantial.

As for the jumper cable question...it's not working for the same reason why
you can't instantly start your car after hooking up the jumper cables.

ok, i just went out and bought a big ass optima yellowtop. same problem,
however i'll give it
the benefit of the doubt and allow it to have time to charge in case it ran
down sitting on the shelf
at the auto store. if this doesn't solve it, i'm lost. new alternator, new
battery, new amp, 2ga wiring direct to the battery.
this is getting expensive to troubleshoot.


"MZ" wrote in message
...
I have an Xtant A4004. It's in three channel mode, the components work
fine, but if the sub hits, the amp puts out no sound on the hit.
Basically
it makes a noise for about .1 seconds and then silence for about 2
seconds,
then it repeats. My installer said it was a bad amp, so I replaced it,
the
new amp does the same thing. Then I was told it was the alternator, so
brilliant me.... I replaced the alternator (granted I wanted a polished
one
anyway and it was an excuse). Same behavior. I'm now wondering if its
the
battery because I left the music running at a normal listening level
with
the car off (obviously without the sub hooked up) and the battery died
after
about 20 minutes. However I THOUGHT I'd be able to test the battery by
jumping it to another car. I hooked up the sub again but had the same
behavior. So, is this a valid battery test, or if not, why? Next step
is
to pull the battery out of my wifes car and hook that up and see what
happens, but I was hoping to avoid having to do that with a pair of
jumper
cables.

That actually sounds like a classic symptom of a bad battery to me.
Contrary to what many people in here claim, the battery plays an active
role
in powering the audio system. Anyone who has ever disconnected the
battery
while the car is running (not recommended if you value your car!) will see
the exact symptoms you're describing when trying to run their audio
system.
The amp is essentially shutting off and turning back on everytime the
current draw is substantial.

As for the jumper cable question...it's not working for the same reason
why
you can't instantly start your car after hooking up the jumper cables.

actually now that i think about it, arent yellow tops designed to give you
full output until theyre dead?

"Rob" wrote in message
...
ok, i just went out and bought a big ass optima yellowtop. same problem,
however i'll give it
the benefit of the doubt and allow it to have time to charge in case it
ran
down sitting on the shelf
at the auto store. if this doesn't solve it, i'm lost. new alternator,
new
battery, new amp, 2ga wiring direct to the battery.
this is getting expensive to troubleshoot.


"MZ" wrote in message
...
I have an Xtant A4004. It's in three channel mode, the components
work
fine, but if the sub hits, the amp puts out no sound on the hit.
Basically
it makes a noise for about .1 seconds and then silence for about 2
seconds,
then it repeats. My installer said it was a bad amp, so I replaced
it,
the
new amp does the same thing. Then I was told it was the alternator,
so
brilliant me.... I replaced the alternator (granted I wanted a
polished
one
anyway and it was an excuse). Same behavior. I'm now wondering if
its
the
battery because I left the music running at a normal listening level
with
the car off (obviously without the sub hooked up) and the battery died
after
about 20 minutes. However I THOUGHT I'd be able to test the battery
by
jumping it to another car. I hooked up the sub again but had the same
behavior. So, is this a valid battery test, or if not, why? Next
step
is
to pull the battery out of my wifes car and hook that up and see what
happens, but I was hoping to avoid having to do that with a pair of
jumper
cables.

That actually sounds like a classic symptom of a bad battery to me.
Contrary to what many people in here claim, the battery plays an active
role
in powering the audio system. Anyone who has ever disconnected the
battery
while the car is running (not recommended if you value your car!) will
see
the exact symptoms you're describing when trying to run their audio
system.
The amp is essentially shutting off and turning back on everytime the
current draw is substantial.

As for the jumper cable question...it's not working for the same reason
why
you can't instantly start your car after hooking up the jumper cables.

Yikes. Kind of an expensive option for just a replacement. Walmart
batteries are certainly good enough. Sears puts their Die Hards on sale
every so often too.

Anyway, I think the first thing you have to determine is what the amp is
doing when it stops. Is it shutting off? Is it going into protection?
There should be indicator lights to tell you this.

--
Mark
remove "remove" and "spam" to reply


"Rob" wrote in message
...
ok, i just went out and bought a big ass optima yellowtop. same problem,
however i'll give it
the benefit of the doubt and allow it to have time to charge in case it
ran
down sitting on the shelf
at the auto store. if this doesn't solve it, i'm lost. new alternator,
new
battery, new amp, 2ga wiring direct to the battery.
this is getting expensive to troubleshoot.


"MZ" wrote in message
...
I have an Xtant A4004. It's in three channel mode, the components
work
fine, but if the sub hits, the amp puts out no sound on the hit.
Basically
it makes a noise for about .1 seconds and then silence for about 2
seconds,
then it repeats. My installer said it was a bad amp, so I replaced
it,
the
new amp does the same thing. Then I was told it was the alternator,
so
brilliant me.... I replaced the alternator (granted I wanted a
polished
one
anyway and it was an excuse). Same behavior. I'm now wondering if
its
the
battery because I left the music running at a normal listening level
with
the car off (obviously without the sub hooked up) and the battery died
after
about 20 minutes. However I THOUGHT I'd be able to test the battery
by
jumping it to another car. I hooked up the sub again but had the same
behavior. So, is this a valid battery test, or if not, why? Next
step
is
to pull the battery out of my wifes car and hook that up and see what
happens, but I was hoping to avoid having to do that with a pair of
jumper
cables.

That actually sounds like a classic symptom of a bad battery to me.
Contrary to what many people in here claim, the battery plays an active
role
in powering the audio system. Anyone who has ever disconnected the
battery
while the car is running (not recommended if you value your car!) will
see
the exact symptoms you're describing when trying to run their audio
system.
The amp is essentially shutting off and turning back on everytime the
current draw is substantial.

As for the jumper cable question...it's not working for the same reason
why
you can't instantly start your car after hooking up the jumper cables.

i'll be running a PC in the car too, so wanted to make sure the battery was
up to the task. the amp does not go into protected mode. nor give any
indication anything is wrong. the only thing i notice is after the sound
cuts out, the idle of the car jumps up a 100rpm or so for a split second
then drops back down. the amp makes a brief noise again, cuts out, car idles
higher, drops back down. over and over.

"MZ" wrote in message
...
Yikes. Kind of an expensive option for just a replacement. Walmart
batteries are certainly good enough. Sears puts their Die Hards on sale
every so often too.

Anyway, I think the first thing you have to determine is what the amp is
doing when it stops. Is it shutting off? Is it going into protection?
There should be indicator lights to tell you this.

--
Mark
remove "remove" and "spam" to reply


"Rob" wrote in message
...
ok, i just went out and bought a big ass optima yellowtop. same
problem,
however i'll give it
the benefit of the doubt and allow it to have time to charge in case it
ran
down sitting on the shelf
at the auto store. if this doesn't solve it, i'm lost. new alternator,
new
battery, new amp, 2ga wiring direct to the battery.
this is getting expensive to troubleshoot.


"MZ" wrote in message
...
I have an Xtant A4004. It's in three channel mode, the components
work
fine, but if the sub hits, the amp puts out no sound on the hit.
Basically
it makes a noise for about .1 seconds and then silence for about 2
seconds,
then it repeats. My installer said it was a bad amp, so I replaced
it,
the
new amp does the same thing. Then I was told it was the alternator,
so
brilliant me.... I replaced the alternator (granted I wanted a
polished
one
anyway and it was an excuse). Same behavior. I'm now wondering if
its
the
battery because I left the music running at a normal listening level
with
the car off (obviously without the sub hooked up) and the battery
died
after
about 20 minutes. However I THOUGHT I'd be able to test the battery
by
jumping it to another car. I hooked up the sub again but had the
same
behavior. So, is this a valid battery test, or if not, why? Next
step
is
to pull the battery out of my wifes car and hook that up and see
what
happens, but I was hoping to avoid having to do that with a pair of
jumper
cables.

That actually sounds like a classic symptom of a bad battery to me.
Contrary to what many people in here claim, the battery plays an
active
role
in powering the audio system. Anyone who has ever disconnected the
battery
while the car is running (not recommended if you value your car!) will
see
the exact symptoms you're describing when trying to run their audio
system.
The amp is essentially shutting off and turning back on everytime the
current draw is substantial.

As for the jumper cable question...it's not working for the same
reason
why
you can't instantly start your car after hooking up the jumper cables.

i'll be running a PC in the car too, so wanted to make sure the battery
was
up to the task.

What are you using? Mine draws less than 5 amps.

the amp does not go into protected mode. nor give any
indication anything is wrong. the only thing i notice is after the sound
cuts out, the idle of the car jumps up a 100rpm or so for a split second
then drops back down. the amp makes a brief noise again, cuts out, car
idles
higher, drops back down. over and over.

So the power light is staying on (and not dimming - the power light on some
amps stay on a bit)?

Other possibilities include:
- head unit's remote output is intermittent for whatever reason (wouldn't
really explain the 100rpm thing though).
- you have an overvoltage situation (I doubt this is the case since you
replaced your alternator)
- amp is broken
- head unit is broken
- poor power connections somewhere down the line - have you checked the
ground from your battery to the chassis? Have you checked your battery
cables?

I can't think of any others off the top of my head. What you need to do is
start isolating components.

"MZ" wrote in message
...
i'll be running a PC in the car too, so wanted to make sure the battery
was
up to the task.

What are you using? Mine draws less than 5 amps.


just a laptop but i might be leaving it in standby mode rather than powered
off for a day or two at a time.

the amp does not go into protected mode. nor give any
indication anything is wrong. the only thing i notice is after the sound
cuts out, the idle of the car jumps up a 100rpm or so for a split second
then drops back down. the amp makes a brief noise again, cuts out, car
idles
higher, drops back down. over and over.

So the power light is staying on (and not dimming - the power light on
some
amps stay on a bit)?


yes, there are three lights on the amp, power, thermal protection and
current overload. only the power is on and does not dim.

Other possibilities include:
- head unit's remote output is intermittent for whatever reason (wouldn't
really explain the 100rpm thing though).

it also wouldnt explain why the component speakers have no problems ever
(even when the sub is doing its strange thing the other two channels
continue to function properly).

- you have an overvoltage situation (I doubt this is the case since you
replaced your alternator)
- amp is broken

could very well be

- head unit is broken

again i dont think so since the components work fine

- poor power connections somewhere down the line - have you checked the
ground from your battery to the chassis? Have you checked your battery
cables?


yes, no problem here. 2ga wire running straight to the battery including
the ground, connections are solid. ive also tried grounding to the chassis
per someone elses suggestion.

I can't think of any others off the top of my head. What you need to do
is
start isolating components.



i need to find someplace willing to bench test the amp at this point i
think. i cant imagine having 2 new amps with the same identical problem,
but hey, some people win the lottery at 10,000,000:1 too.

Other possibilities include:
- head unit's remote output is intermittent for whatever reason
(wouldn't
really explain the 100rpm thing though).

it also wouldnt explain why the component speakers have no problems ever
(even when the sub is doing its strange thing the other two channels
continue to function properly).

It appears I overlooked this in your original post. This is very
interesting. Based on this, it seems unlikely that it would be a power
situation. Is the sub input on the amp receiving a separate input from the
head unit?

i need to find someplace willing to bench test the amp at this point i
think. i cant imagine having 2 new amps with the same identical problem,
but hey, some people win the lottery at 10,000,000:1 too.

You're right. It doesn't happen often, but it happens. There is still the
possibility that it's the head unit, only if it has a separate sub out that
you're using.

"MZ" wrote in message
...


You're right. It doesn't happen often, but it happens. There is still
the
possibility that it's the head unit, only if it has a separate sub out
that
you're using.


no seperate out from the head unit. just L/R run into the amp, then you
feed a set of L/R outs from the front channels into a L/R input for the
sub/rear channel. three channel mode you just use the two outside +/-
poles, no settings or jumpers, for four you use both sets of rear L/R.
writing this makes me think there could be an issue from the outs of the
front to the ins of the rear, but its just a standard set of RCA cables and
clearly the rear is getting a signal. perhaps i can run the outs from the
front into a boombox with RCA ins and see if it cuts in and out. that would
be a good test. ok im thinking again . i assume you need to do this
because the crossover circuitry sits between the front inputs and the
outputs. then again maybe not since you could run the rear channels at full
range. ok im babbling now, i have more stuff to go test .

"Rob" wrote in message
...

"MZ" wrote in message
...


You're right. It doesn't happen often, but it happens. There is still
the
possibility that it's the head unit, only if it has a separate sub out
that
you're using.


no seperate out from the head unit. just L/R run into the amp, then you
feed a set of L/R outs from the front channels into a L/R input for the
sub/rear channel. three channel mode you just use the two outside +/-
poles, no settings or jumpers, for four you use both sets of rear L/R.
writing this makes me think there could be an issue from the outs of the
front to the ins of the rear, but its just a standard set of RCA cables
and
clearly the rear is getting a signal. perhaps i can run the outs from the
front into a boombox with RCA ins and see if it cuts in and out. that
would
be a good test. ok im thinking again . i assume you need to do this
because the crossover circuitry sits between the front inputs and the
outputs. then again maybe not since you could run the rear channels at
full
range. ok im babbling now, i have more stuff to go test .



Are you sure it's not the sub?

yes, i carted out one of my home speakers and hooked it up, it did the same
thing.

"KaeZoo" wrote in message
...

"Rob" wrote in message
...

"MZ" wrote in message
...


You're right. It doesn't happen often, but it happens. There is
still
the
possibility that it's the head unit, only if it has a separate sub out
that
you're using.


no seperate out from the head unit. just L/R run into the amp, then you
feed a set of L/R outs from the front channels into a L/R input for the
sub/rear channel. three channel mode you just use the two outside +/-
poles, no settings or jumpers, for four you use both sets of rear L/R.
writing this makes me think there could be an issue from the outs of the
front to the ins of the rear, but its just a standard set of RCA cables
and
clearly the rear is getting a signal. perhaps i can run the outs from
the
front into a boombox with RCA ins and see if it cuts in and out. that
would
be a good test. ok im thinking again . i assume you need to do this
because the crossover circuitry sits between the front inputs and the
outputs. then again maybe not since you could run the rear channels at
full
range. ok im babbling now, i have more stuff to go test .



Are you sure it's not the sub?

Well, my fluke will only measure up to 2 amps unfortunately. However I
tried swaping around inputs and outputs, no difference, but I did notice if
I turned the gain way down and set the xover for the sub to full range, the
sub worked, however it was pretty distorted... on the lows!!!! it sounded
ok on mids. It's sounding more and more like this amp is hosed.

"Rob" wrote in message
...
yes, i carted out one of my home speakers and hooked it up, it did the
same
thing.

"KaeZoo" wrote in message
...

"Rob" wrote in message
...

"MZ" wrote in message
...


You're right. It doesn't happen often, but it happens. There is
still
the
possibility that it's the head unit, only if it has a separate sub
out
that
you're using.


no seperate out from the head unit. just L/R run into the amp, then
you
feed a set of L/R outs from the front channels into a L/R input for
the
sub/rear channel. three channel mode you just use the two outside
+/-
poles, no settings or jumpers, for four you use both sets of rear L/R.
writing this makes me think there could be an issue from the outs of
the
front to the ins of the rear, but its just a standard set of RCA
cables
and
clearly the rear is getting a signal. perhaps i can run the outs from
the
front into a boombox with RCA ins and see if it cuts in and out. that
would
be a good test. ok im thinking again . i assume you need to do this
because the crossover circuitry sits between the front inputs and the
outputs. then again maybe not since you could run the rear channels
at
full
range. ok im babbling now, i have more stuff to go test .



Are you sure it's not the sub?

Hi Rob,

You could have a bad battery, but it sounds as if the more probably
cause is a high resistant connection (causing a voltage drop). I
would suggest that you have your battery and charging system tested at
an auto parts or battery store and take a voltmeter and carefully
check each connection (including the grounds) for a voltage drop.
Corrosion and oxidation cuse this and cleaning to bare metal will help
considerably.

For more information on testing a battery, please see Section 4 in the
Car and Deep Cycle Battery FAQ on www.batteryfaq.org and Section 5 for
charging system sizing.

Kindest regards,

BiLL.......

On Thu, 13 May 2004 23:56:01 GMT, "Rob" wrote:

I have an Xtant A4004. It's in three channel mode, the components work
fine, but if the sub hits, the amp puts out no sound on the hit. Basically
it makes a noise for about .1 seconds and then silence for about 2 seconds,
then it repeats. My installer said it was a bad amp, so I replaced it, the
new amp does the same thing. Then I was told it was the alternator, so
brilliant me.... I replaced the alternator (granted I wanted a polished one
anyway and it was an excuse). Same behavior. I'm now wondering if its the
battery because I left the music running at a normal listening level with
the car off (obviously without the sub hooked up) and the battery died after
about 20 minutes. However I THOUGHT I'd be able to test the battery by
jumping it to another car. I hooked up the sub again but had the same
behavior. So, is this a valid battery test, or if not, why? Next step is
to pull the battery out of my wifes car and hook that up and see what
happens, but I was hoping to avoid having to do that with a pair of jumper
cables.

"Rob" wrote in message .. .
Well, my fluke will only measure up to 2 amps unfortunately. However I
tried swaping around inputs and outputs, no difference, but I did notice if
I turned the gain way down and set the xover for the sub to full range, the
sub worked, however it was pretty distorted... on the lows!!!! it sounded
ok on mids. It's sounding more and more like this amp is hosed.



I may be stating the obvious, but, have you checked your ground.
Namely where it attaches to the chasis? I have seen these come loose
or become fouled and the amp tries to derive ground from the HU. This
will cause the amp to go into protect due to the lack of a stiff
ground, sometimes the HU RCA ground is referenced through a couple of
resistors. Does the amp turn on without the RCA's connected, If so
try running a portable CD player into the amp without the HU RCA's
connected, Did the problem worsen?

Give that ground wire and connection a good look over, yeah it may
read a really low impedance but can it carry big current?

When the amp cuts out it is protecting itself, probably from under
voltage. Sometimes it will protect itself when a driver (transistor)
opens and you only get 1/2 a waveform on the output, but you had the
problem with 2 amps and output devices / drivers opening are not that
common, usually they short and it's really obvious when that happens.
It won't turn on, it will shread speakers, or it will cycle in and out
of protect immediately and just burp when it comes on.

Chad