[direct]

Ok, actually post install troubles. After installation, everything work
fine. Over the next month, some humming/noise developed, and was
occassionally quite bad. Then my wife stuffed the trunk full of stuff and
shoved the amp and sub-box to the side resulting in some wiring problems. I
replaced the rca cable from the head-unit to the amp and now there is no
sound when configured the same way as originally installed. BUT

- if I only plug one channel of the rca into the amplifer, there is sound
- if I directly connect an ipod to both channels of the amp, there is sound.
(so probably not an amp issue)
- if I just touch the post on the rca cable to the inside of the jack on the
amp, there is sound. Even though the outer part of the cable is not yet in
contact with the jack!
- in all cases, there is either no sound, or clear sound with no apparent
noise/buzzing

ideas?

[MOSFET]

OK, problems like this can seem overwhelming so you want to have a
troubleshooting "plan" so you can first identify the source of the problem.
Before I give you any advice, PLEASE go to:

http://www.mobileaudio.com/rac-faq/

This is the FAQ for this group that has been added to and mended for over 20
years. It is FILLED with usefull troubleshooting advice from engineers and
pioneers in the car audio industry. There is a TREMENDOUS amount of
knowledge that can be gained from that site.

Like I said, you first need to find the source of the problem so break it
down into small tests. For instance, start with taking your Mp3 player and
using a short set of RCA's, take it to the trunk and connect it directly to
your sub-amp. This will tell you a lot. Like if there is a problem with
the connection going from the dash to the back of the car (bad cables).

If it still works poorly try using a different set of speakers coonected
directly to the sub amp using a short cable, like a small set of test
speakers YOU KNOW work. If the speakers seem to work fine then there is a
problem with your subwoofer connections.

Again, break this up into small tests you KNOW should work. Hopefully, it
is not a problem with your sub amp but I suspect it is a wiring issue (these
kind of problems usually are).

Again, use the website I gave you as there is a comprehensive step-by-step
troubleshooting guide for problems just such as yours. Good luck. Let us
know how it's going.

MOSFET


"direct" wrote in message news:h9q6m.36040$PH1.34965@edtnps82...
Ok, actually post install troubles. After installation, everything work
fine. Over the next month, some humming/noise developed, and was
occassionally quite bad. Then my wife stuffed the trunk full of stuff and
shoved the amp and sub-box to the side resulting in some wiring problems.
I replaced the rca cable from the head-unit to the amp and now there is no
sound when configured the same way as originally installed. BUT

- if I only plug one channel of the rca into the amplifer, there is sound
- if I directly connect an ipod to both channels of the amp, there is
sound. (so probably not an amp issue)
- if I just touch the post on the rca cable to the inside of the jack on
the amp, there is sound. Even though the outer part of the cable is not
yet in contact with the jack!
- in all cases, there is either no sound, or clear sound with no apparent
noise/buzzing

ideas?

[direct]

Thanks - I did read the entirety of the faq before posting. Perhaps I'm such
a "newbie" that I couldn't even identify the appropriate trouble shooting
steps!

I appreciate your speedy response, however I wonder if perhaps I need to
re-word some of my message as it seems I was unable to appropriately convey
what I'd accomplished to this point.

For example, you suggest "start with taking your Mp3 player and using a
short set of RCA's, take it to the trunk and connect it directly to your
sub-amp." And in my original posting, I stated "if I directly connect an
ipod to both channels of the amp ..."

I'm having trouble figuring out what steps to take next in determining the
problem. Just one more clue ...

please?


"MOSFET" wrote in message
m...
OK, problems like this can seem overwhelming so you want to have a
troubleshooting "plan" so you can first identify the source of the
problem. Before I give you any advice, PLEASE go to:

http://www.mobileaudio.com/rac-faq/

This is the FAQ for this group that has been added to and mended for over
20 years. It is FILLED with usefull troubleshooting advice from engineers
and pioneers in the car audio industry. There is a TREMENDOUS amount of
knowledge that can be gained from that site.

Like I said, you first need to find the source of the problem so break it
down into small tests. For instance, start with taking your Mp3 player
and using a short set of RCA's, take it to the trunk and connect it
directly to your sub-amp. This will tell you a lot. Like if there is a
problem with the connection going from the dash to the back of the car
(bad cables).

If it still works poorly try using a different set of speakers coonected
directly to the sub amp using a short cable, like a small set of test
speakers YOU KNOW work. If the speakers seem to work fine then there is a
problem with your subwoofer connections.

Again, break this up into small tests you KNOW should work. Hopefully, it
is not a problem with your sub amp but I suspect it is a wiring issue
(these kind of problems usually are).

Again, use the website I gave you as there is a comprehensive step-by-step
troubleshooting guide for problems just such as yours. Good luck. Let us
know how it's going.

MOSFET


"direct" wrote in message news:h9q6m.36040$PH1.34965@edtnps82...
Ok, actually post install troubles. After installation, everything work
fine. Over the next month, some humming/noise developed, and was
occassionally quite bad. Then my wife stuffed the trunk full of stuff and
shoved the amp and sub-box to the side resulting in some wiring problems.
I replaced the rca cable from the head-unit to the amp and now there is
no sound when configured the same way as originally installed. BUT

- if I only plug one channel of the rca into the amplifer, there is sound
- if I directly connect an ipod to both channels of the amp, there is
sound. (so probably not an amp issue)
- if I just touch the post on the rca cable to the inside of the jack on
the amp, there is sound. Even though the outer part of the cable is not
yet in contact with the jack!
- in all cases, there is either no sound, or clear sound with no apparent
noise/buzzing

ideas?

[MOSFET]

Sorry, I wrote that in a haste. I will reread your original posting and see
if anyhting comes to mind I missed. Frankly, if you have already read our
FAQ, I probably won't have much to add as it has the most comprehensive
troubleshooting flow-chart.

Good luck,
MOSFET

"direct" wrote in message news:_9r6m.36043$PH1.949@edtnps82...
Thanks - I did read the entirety of the faq before posting. Perhaps I'm
such a "newbie" that I couldn't even identify the appropriate trouble
shooting steps!

I appreciate your speedy response, however I wonder if perhaps I need to
re-word some of my message as it seems I was unable to appropriately
convey what I'd accomplished to this point.

For example, you suggest "start with taking your Mp3 player and using a
short set of RCA's, take it to the trunk and connect it directly to your
sub-amp." And in my original posting, I stated "if I directly connect an
ipod to both channels of the amp ..."

I'm having trouble figuring out what steps to take next in determining the
problem. Just one more clue ...

please?


"MOSFET" wrote in message
m...
OK, problems like this can seem overwhelming so you want to have a
troubleshooting "plan" so you can first identify the source of the
problem. Before I give you any advice, PLEASE go to:

http://www.mobileaudio.com/rac-faq/

This is the FAQ for this group that has been added to and mended for over
20 years. It is FILLED with usefull troubleshooting advice from
engineers and pioneers in the car audio industry. There is a TREMENDOUS
amount of knowledge that can be gained from that site.

Like I said, you first need to find the source of the problem so break it
down into small tests. For instance, start with taking your Mp3 player
and using a short set of RCA's, take it to the trunk and connect it
directly to your sub-amp. This will tell you a lot. Like if there is a
problem with the connection going from the dash to the back of the car
(bad cables).

If it still works poorly try using a different set of speakers coonected
directly to the sub amp using a short cable, like a small set of test
speakers YOU KNOW work. If the speakers seem to work fine then there is
a problem with your subwoofer connections.

Again, break this up into small tests you KNOW should work. Hopefully,
it is not a problem with your sub amp but I suspect it is a wiring issue
(these kind of problems usually are).

Again, use the website I gave you as there is a comprehensive
step-by-step troubleshooting guide for problems just such as yours. Good
luck. Let us know how it's going.

MOSFET


"direct" wrote in message
news:h9q6m.36040$PH1.34965@edtnps82...
Ok, actually post install troubles. After installation, everything work
fine. Over the next month, some humming/noise developed, and was
occassionally quite bad. Then my wife stuffed the trunk full of stuff
and shoved the amp and sub-box to the side resulting in some wiring
problems. I replaced the rca cable from the head-unit to the amp and now
there is no sound when configured the same way as originally installed.
BUT

- if I only plug one channel of the rca into the amplifer, there is
sound
- if I directly connect an ipod to both channels of the amp, there is
sound. (so probably not an amp issue)
- if I just touch the post on the rca cable to the inside of the jack on
the amp, there is sound. Even though the outer part of the cable is not
yet in contact with the jack!
- in all cases, there is either no sound, or clear sound with no
apparent noise/buzzing

ideas?

[mlewis]

try redoing the grounds for your system. also check all the switches
on your amp. and settings for your head unit. the buzzing sound you
hear is often a case of a bad ground.. the system tries to find a
ground through other avenues ie the speakers or rca cables an causes
buzzing etc.. it is possible that there was soem damage to the system
when she moved things around ... wires touching things they shouldn't
is often a bad thing.

also... the inner part of the rca cable carries the positive signal
from the head unit.. the outer part carries the ground.. since there
is a ground already there.. it doesn't need it to make sound.. not
the correct way to hook things up though.. and can cause damage to the
system if left that way for an extended period

since it does work with the ipod.. your most likely correct in
assuming the trouble is elsewhere.. ( but not always always! )
is this a "simple" system? only a head unit an amp with speakers? or
are there more toys in the loop? if the latter.. try removing them for
testing. hopefully this is in vain and you have already solved to
trouble!


direct wrote:
Ok, actually post install troubles. After installation, everything work
fine. Over the next month, some humming/noise developed, and was
occassionally quite bad. Then my wife stuffed the trunk full of stuff and
shoved the amp and sub-box to the side resulting in some wiring problems. I
replaced the rca cable from the head-unit to the amp and now there is no
sound when configured the same way as originally installed. BUT

- if I only plug one channel of the rca into the amplifer, there is sound


- if I directly connect an ipod to both channels of the amp, there is sound.
(so probably not an amp issue)
- if I just touch the post on the rca cable to the inside of the jack on the
amp, there is sound. Even though the outer part of the cable is not yet in
contact with the jack!


- in all cases, there is either no sound, or clear sound with no apparent
noise/buzzing

ideas?





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[MOSFET]

(so probably not an amp issue)
- if I just touch the post on the rca cable to the inside of the jack on
the
amp, there is sound. Even though the outer part of the cable is not yet
in
contact with the jack!


Mlewis is exactly right, your amp is grounded and therefore has it's own
negative potential whereby electrons are sent back through the car body back
to the alternator if car is on, battery if car is off. This is the case
with EVERY electrical device in your car. So yes, with most amps I have
ALSO observed that giving it the RCA center pin only (the positive side)
WILL give you sound as all other non-postive circuits in your amp including
the body of the amp itself are gounded through the car and therefore have a
negative potential to send BACK those elctrons that are being sent TO your
amp via the positve center pin. Basically, what I'm trying to say is that
the fact your amp does this is NOT indicative of a problem with your
amplifier or HU. I believe mlewis was making the same point.

And, again, mlewis is exactly correct, you would NOT want to connect your
RCA's this way OR, as was common in the past, speakers (the negative
connector) to the chassis of the car although it may "work" or produce
sound, you introduce a rats nest of problems including dangerous impedences
presented to your amp (if speakers) and noise problems if talking about
RCA's, well, and speakers as well.

Going back to your original question, frankly I haven't written anything
back as I didn't really have anything of value to say. If your iPod works
when connected to your amplifier, and I mean both channels works. Then we
can exclude the amp as you already surmised. As you OBVIOUSLY must have
realized by now the problem is either your RCA's connecting the HU to the
amp, OR the HU itself. And again, this is probably redundant from the FAQ
troubleshooting flow-chart, but the NEXT thing you would do is connect a
small stereo to your HU using the HU RCA outputs as a source. MANY
boomboxes have AUX inputs these days with the popularity of the iPod.
Simply getting your hands on one of these and connecting that to your HU RCA
outs will tell you if there is a problem with those outputs. If THEY work
just fine over a boombox, then clearly you have a wiring problem with your
RCA's that run to your amp.

Again, A) you have probably thought through the above or have already
performed this and B) I'm quite sure this is covered in the troubleshooting
portion of our FAQ. That's honestly why I haven't responded, not to ignore
you, but to spare you boredom.

If there is ANOTHER problem your having, then we will need more info. I did
CAREFULLY reread your first post and if there is flat out NO SOUND when your
RCA's are connected, then you either have bad RCA's or a bad HU. It's
really that simple as we can rule out the amp.

Now, if the issue is NOISE, well then that's a different kettle of fish
requiring different stratagies as there are differnet types of noise that
can enter a system (ground-loops, EMI, ect.). Again, the FAQ has an
excellent portion dealing with induced noise issues and how to combat those.

Well, I'm sure I didn't help you at all, but I didn't want you to think I
was blowing you off.

Good luck,

MOSFET