[headrott]

I am installing 2 (2 channel, obviously) amps (an alpine 3548(for the
front) and an alpine 3522 (for the rear)into my car (1993 BMW 318is). I
have the positive cables hooked directly to the battery and and the
ground cables grounded to the floorboard.
The problem is that when I turn on the HU, the amps power up fine but
when I go to turn up the volume (from 0) there is a loud thump on all 4
speakers and the audio that comes out is very weak (even when you turn
it up loud). Also, sometimes on the back speakers (comming from the
3522) the speakers make a constant very fast thump-thump-thump-thump.
The volume of this is a medium volume even when the volume on the HU is
only on 1 or 2. I have tried messing with the ground wires multiple
times, but with no luck. I am at my knowledges end, so please someone
help me figure this out. Tank you for your time and help.

[MOSFET]

What HU are you using? Are you using line-level RCA inputs or speaker-level
inputs? So both amps do EXACTLY the same thing? Do they each have seperate
inputs from the HU (like front and rear)? In other words, are you Y-ing a
signal and then sending that to the amps or do they each have their own
seperate inputs from the HU?

If you are sending a front signal to the 3548 and then a rear to the 3522
(I've used that amp, it's a GREAT little amp), is each amp doing EXACTLY the
same thing? If so, it's safe to assume that the problem is related to your
HU or how you have your HU connected to the amps, not the amps themselves.
But we need a bit more info first before we can narrow the problem down.

MOSFET

"headrott" wrote in message
oups.com...
I am installing 2 (2 channel, obviously) amps (an alpine 3548(for the
front) and an alpine 3522 (for the rear)into my car (1993 BMW 318is). I
have the positive cables hooked directly to the battery and and the
ground cables grounded to the floorboard.
The problem is that when I turn on the HU, the amps power up fine but
when I go to turn up the volume (from 0) there is a loud thump on all 4
speakers and the audio that comes out is very weak (even when you turn
it up loud). Also, sometimes on the back speakers (comming from the
3522) the speakers make a constant very fast thump-thump-thump-thump.
The volume of this is a medium volume even when the volume on the HU is
only on 1 or 2. I have tried messing with the ground wires multiple
times, but with no luck. I am at my knowledges end, so please someone
help me figure this out. Tank you for your time and help.

[headrott]

I am using an Alpine 7525 head unit, and line level RCA with seperate
outputs from the HU meaning seperate inputs on the amps. No Y-ing
involved.
I don't think it's the HU because I had 2 3522's hooked up to it
(front/rear) and they worked fine. Then the front 3522 was stolen. I
was using just the rear 3522 and it worked fine (after the front was
taken). I then rewired my car (new positive and negative wires, but the
same RCA cables and speaker cables) and that's when the problems
started.

Yje problems aren't exactly the same in the front and rear, but
extremely similar. It's mainly the rear that does the rapid
thump-thump-thump. But both the front and rear have very faint and
distorted sounding signals coming out of them. Thanks for your help.

MOSFET wrote:
What HU are you using? Are you using line-level RCA inputs or speaker-level
inputs? So both amps do EXACTLY the same thing? Do they each have seperate
inputs from the HU (like front and rear)? In other words, are you Y-ing a
signal and then sending that to the amps or do they each have their own
seperate inputs from the HU?

If you are sending a front signal to the 3548 and then a rear to the 3522
(I've used that amp, it's a GREAT little amp), is each amp doing EXACTLY the
same thing? If so, it's safe to assume that the problem is related to your
HU or how you have your HU connected to the amps, not the amps themselves.
But we need a bit more info first before we can narrow the problem down.

MOSFET

"headrott" wrote in message
oups.com...
I am installing 2 (2 channel, obviously) amps (an alpine 3548(for the
front) and an alpine 3522 (for the rear)into my car (1993 BMW 318is). I
have the positive cables hooked directly to the battery and and the
ground cables grounded to the floorboard.
The problem is that when I turn on the HU, the amps power up fine but
when I go to turn up the volume (from 0) there is a loud thump on all 4
speakers and the audio that comes out is very weak (even when you turn
it up loud). Also, sometimes on the back speakers (comming from the
3522) the speakers make a constant very fast thump-thump-thump-thump.
The volume of this is a medium volume even when the volume on the HU is
only on 1 or 2. I have tried messing with the ground wires multiple
times, but with no luck. I am at my knowledges end, so please someone
help me figure this out. Tank you for your time and help.

[The Lull]

My guess goes on the ground.
~The Lull
headrott wrote:
I am using an Alpine 7525 head unit, and line level RCA with seperate
outputs from the HU meaning seperate inputs on the amps. No Y-ing
involved.
I don't think it's the HU because I had 2 3522's hooked up to it
(front/rear) and they worked fine. Then the front 3522 was stolen. I
was using just the rear 3522 and it worked fine (after the front was
taken). I then rewired my car (new positive and negative wires, but the
same RCA cables and speaker cables) and that's when the problems
started.

Yje problems aren't exactly the same in the front and rear, but
extremely similar. It's mainly the rear that does the rapid
thump-thump-thump. But both the front and rear have very faint and
distorted sounding signals coming out of them. Thanks for your help.

MOSFET wrote:
What HU are you using? Are you using line-level RCA inputs or speaker-level
inputs? So both amps do EXACTLY the same thing? Do they each have seperate
inputs from the HU (like front and rear)? In other words, are you Y-ing a
signal and then sending that to the amps or do they each have their own
seperate inputs from the HU?

If you are sending a front signal to the 3548 and then a rear to the 3522
(I've used that amp, it's a GREAT little amp), is each amp doing EXACTLY the
same thing? If so, it's safe to assume that the problem is related to your
HU or how you have your HU connected to the amps, not the amps themselves.
But we need a bit more info first before we can narrow the problem down.

MOSFET

"headrott" wrote in message
oups.com...
I am installing 2 (2 channel, obviously) amps (an alpine 3548(for the
front) and an alpine 3522 (for the rear)into my car (1993 BMW 318is). I
have the positive cables hooked directly to the battery and and the
ground cables grounded to the floorboard.
The problem is that when I turn on the HU, the amps power up fine but
when I go to turn up the volume (from 0) there is a loud thump on all 4
speakers and the audio that comes out is very weak (even when you turn
it up loud). Also, sometimes on the back speakers (comming from the
3522) the speakers make a constant very fast thump-thump-thump-thump.
The volume of this is a medium volume even when the volume on the HU is
only on 1 or 2. I have tried messing with the ground wires multiple
times, but with no luck. I am at my knowledges end, so please someone
help me figure this out. Tank you for your time and help.

[MOSFET]

Nothing immediately comes to mind as a problem. So you will likely have to
perform some tests.

The first thing I would do is get your hands on a "walkman" or iPod or any
portable music source and run that directly into your amps. If the problem
goes away we can rule out your amps. If the problem still occurs then it
may be a grounding issue or some other type of electrical issue with your
car (have you checked the voltage with a multimeter? Are you getting AT
LEAST 12 volts to those amps?).

If the problem goes away while using a portable music source, then the
problem is upstream perhaps with your HU or bad RCA's. If you just use the
speaker outputs of the HU does the problem occur? If so, then we can safely
assume it's the HU and perhaps you have a bad ground. It COULD be RF
interference coming through your RCA's although that is EXTREMELY rare (I
know, cable makers make you think that this is a big concern, but ground
loops lend to be the problem 95% of the time when we're talking induced
noise).

Anyway, check these things out, and let us know,

MOSFET

"The Lull" wrote in message
ups.com...
My guess goes on the ground.
~The Lull
headrott wrote:
I am using an Alpine 7525 head unit, and line level RCA with seperate
outputs from the HU meaning seperate inputs on the amps. No Y-ing
involved.
I don't think it's the HU because I had 2 3522's hooked up to it
(front/rear) and they worked fine. Then the front 3522 was stolen. I
was using just the rear 3522 and it worked fine (after the front was
taken). I then rewired my car (new positive and negative wires, but the
same RCA cables and speaker cables) and that's when the problems
started.

Yje problems aren't exactly the same in the front and rear, but
extremely similar. It's mainly the rear that does the rapid
thump-thump-thump. But both the front and rear have very faint and
distorted sounding signals coming out of them. Thanks for your help.

MOSFET wrote:
What HU are you using? Are you using line-level RCA inputs or
speaker-level
inputs? So both amps do EXACTLY the same thing? Do they each have
seperate
inputs from the HU (like front and rear)? In other words, are you
Y-ing a
signal and then sending that to the amps or do they each have their
own
seperate inputs from the HU?

If you are sending a front signal to the 3548 and then a rear to the
3522
(I've used that amp, it's a GREAT little amp), is each amp doing
EXACTLY the
same thing? If so, it's safe to assume that the problem is related to
your
HU or how you have your HU connected to the amps, not the amps
themselves.
But we need a bit more info first before we can narrow the problem
down.

MOSFET

"headrott" wrote in message
oups.com...
I am installing 2 (2 channel, obviously) amps (an alpine 3548(for
the
front) and an alpine 3522 (for the rear)into my car (1993 BMW
318is). I
have the positive cables hooked directly to the battery and and the
ground cables grounded to the floorboard.
The problem is that when I turn on the HU, the amps power up fine
but
when I go to turn up the volume (from 0) there is a loud thump on
all 4
speakers and the audio that comes out is very weak (even when you
turn
it up loud). Also, sometimes on the back speakers (comming from the
3522) the speakers make a constant very fast
thump-thump-thump-thump.
The volume of this is a medium volume even when the volume on the HU
is
only on 1 or 2. I have tried messing with the ground wires multiple
times, but with no luck. I am at my knowledges end, so please
someone
help me figure this out. Tank you for your time and help.

[Kyle]

Chech the gains on the amp, make sure they aren't set too low.

[headrott]

Hello again,

I found out it is the head unit. I'm guessing it's the pre-amp. I have
2 7525's and I switched the RCA jacks from one and put them on the one
that was having problems, but still the same thing is occurring. It may
be the solder joints on the board? Or a blown capacitor? I'm not sure
though. I tried putting in the other 7525, but the face plate won't
light up. Everything else works fine, but the face lamps don't turn on.
Anyone have any ideas on how to fix these problems. The face lamps not
turning on and/or the pre amp sounding too low of a volume and
distorted? Any help would be appreciated greatly.

Greg
MOSFET wrote:
Nothing immediately comes to mind as a problem. So you will likely have to
perform some tests.

The first thing I would do is get your hands on a "walkman" or iPod or any
portable music source and run that directly into your amps. If the problem
goes away we can rule out your amps. If the problem still occurs then it
may be a grounding issue or some other type of electrical issue with your
car (have you checked the voltage with a multimeter? Are you getting AT
LEAST 12 volts to those amps?).

If the problem goes away while using a portable music source, then the
problem is upstream perhaps with your HU or bad RCA's. If you just use the
speaker outputs of the HU does the problem occur? If so, then we can safely
assume it's the HU and perhaps you have a bad ground. It COULD be RF
interference coming through your RCA's although that is EXTREMELY rare (I
know, cable makers make you think that this is a big concern, but ground
loops lend to be the problem 95% of the time when we're talking induced
noise).

Anyway, check these things out, and let us know,

MOSFET

"The Lull" wrote in message
ups.com...
My guess goes on the ground.
~The Lull
headrott wrote:
I am using an Alpine 7525 head unit, and line level RCA with seperate
outputs from the HU meaning seperate inputs on the amps. No Y-ing
involved.
I don't think it's the HU because I had 2 3522's hooked up to it
(front/rear) and they worked fine. Then the front 3522 was stolen. I
was using just the rear 3522 and it worked fine (after the front was
taken). I then rewired my car (new positive and negative wires, but the
same RCA cables and speaker cables) and that's when the problems
started.

Yje problems aren't exactly the same in the front and rear, but
extremely similar. It's mainly the rear that does the rapid
thump-thump-thump. But both the front and rear have very faint and
distorted sounding signals coming out of them. Thanks for your help.

MOSFET wrote:
What HU are you using? Are you using line-level RCA inputs or
speaker-level
inputs? So both amps do EXACTLY the same thing? Do they each have
seperate
inputs from the HU (like front and rear)? In other words, are you
Y-ing a
signal and then sending that to the amps or do they each have their
own
seperate inputs from the HU?

If you are sending a front signal to the 3548 and then a rear to the
3522
(I've used that amp, it's a GREAT little amp), is each amp doing
EXACTLY the
same thing? If so, it's safe to assume that the problem is related to
your
HU or how you have your HU connected to the amps, not the amps
themselves.
But we need a bit more info first before we can narrow the problem
down.

MOSFET

"headrott" wrote in message
oups.com...
I am installing 2 (2 channel, obviously) amps (an alpine 3548(for
the
front) and an alpine 3522 (for the rear)into my car (1993 BMW
318is). I
have the positive cables hooked directly to the battery and and the
ground cables grounded to the floorboard.
The problem is that when I turn on the HU, the amps power up fine
but
when I go to turn up the volume (from 0) there is a loud thump on
all 4
speakers and the audio that comes out is very weak (even when you
turn
it up loud). Also, sometimes on the back speakers (comming from the
3522) the speakers make a constant very fast
thump-thump-thump-thump.
The volume of this is a medium volume even when the volume on the HU
is
only on 1 or 2. I have tried messing with the ground wires multiple
times, but with no luck. I am at my knowledges end, so please
someone
help me figure this out. Tank you for your time and help.

[headrott]

I forgot to add that I know for sure the lights in the face plate do
work because they light up on the 7525 that has the pre amp issues. I
know it's not the lamps in the face plate themseleves. thanks again.

Greg
headrott wrote:
Hello again,

I found out it is the head unit. I'm guessing it's the pre-amp. I have
2 7525's and I switched the RCA jacks from one and put them on the one
that was having problems, but still the same thing is occurring. It may
be the solder joints on the board? Or a blown capacitor? I'm not sure
though. I tried putting in the other 7525, but the face plate won't
light up. Everything else works fine, but the face lamps don't turn on.
Anyone have any ideas on how to fix these problems. The face lamps not
turning on and/or the pre amp sounding too low of a volume and
distorted? Any help would be appreciated greatly.

Greg
MOSFET wrote:
Nothing immediately comes to mind as a problem. So you will likely have to
perform some tests.

The first thing I would do is get your hands on a "walkman" or iPod or any
portable music source and run that directly into your amps. If the problem
goes away we can rule out your amps. If the problem still occurs then it
may be a grounding issue or some other type of electrical issue with your
car (have you checked the voltage with a multimeter? Are you getting AT
LEAST 12 volts to those amps?).

If the problem goes away while using a portable music source, then the
problem is upstream perhaps with your HU or bad RCA's. If you just use the
speaker outputs of the HU does the problem occur? If so, then we can safely
assume it's the HU and perhaps you have a bad ground. It COULD be RF
interference coming through your RCA's although that is EXTREMELY rare (I
know, cable makers make you think that this is a big concern, but ground
loops lend to be the problem 95% of the time when we're talking induced
noise).

Anyway, check these things out, and let us know,

MOSFET

"The Lull" wrote in message
ups.com...
My guess goes on the ground.
~The Lull
headrott wrote:
I am using an Alpine 7525 head unit, and line level RCA with seperate
outputs from the HU meaning seperate inputs on the amps. No Y-ing
involved.
I don't think it's the HU because I had 2 3522's hooked up to it
(front/rear) and they worked fine. Then the front 3522 was stolen. I
was using just the rear 3522 and it worked fine (after the front was
taken). I then rewired my car (new positive and negative wires, but the
same RCA cables and speaker cables) and that's when the problems
started.

Yje problems aren't exactly the same in the front and rear, but
extremely similar. It's mainly the rear that does the rapid
thump-thump-thump. But both the front and rear have very faint and
distorted sounding signals coming out of them. Thanks for your help.

MOSFET wrote:
What HU are you using? Are you using line-level RCA inputs or
speaker-level
inputs? So both amps do EXACTLY the same thing? Do they each have
seperate
inputs from the HU (like front and rear)? In other words, are you
Y-ing a
signal and then sending that to the amps or do they each have their
own
seperate inputs from the HU?

If you are sending a front signal to the 3548 and then a rear to the
3522
(I've used that amp, it's a GREAT little amp), is each amp doing
EXACTLY the
same thing? If so, it's safe to assume that the problem is related to
your
HU or how you have your HU connected to the amps, not the amps
themselves.
But we need a bit more info first before we can narrow the problem
down.

MOSFET

"headrott" wrote in message
oups.com...
I am installing 2 (2 channel, obviously) amps (an alpine 3548(for
the
front) and an alpine 3522 (for the rear)into my car (1993 BMW
318is). I
have the positive cables hooked directly to the battery and and the
ground cables grounded to the floorboard.
The problem is that when I turn on the HU, the amps power up fine
but
when I go to turn up the volume (from 0) there is a loud thump on
all 4
speakers and the audio that comes out is very weak (even when you
turn
it up loud). Also, sometimes on the back speakers (comming from the
3522) the speakers make a constant very fast
thump-thump-thump-thump.
The volume of this is a medium volume even when the volume on the HU
is
only on 1 or 2. I have tried messing with the ground wires multiple
times, but with no luck. I am at my knowledges end, so please
someone
help me figure this out. Tank you for your time and help.