Amp noise - I am going to torch the entire car soon

[[email protected]]

I have three amps in my Jeep. A month ago, all three were working.
Things were good.

Then I decided to make the system better by building a little cabinet
for the three amps, because I am an idiot and I can't just be happy
with any system, ever. Now I can't get them to work again.

THE PROBLEM: I can hook up any one amp, and it works beautifully with
any speakers. Once I hook up the second amp, loud constant noise
comes through the speakers.

THE ATTEMPTED SOLUTIONS: I have replaced all of the ground wires but
I don't think they're a problem anyway since any amp works with any
set of wires. They're all grounded to separate points on the
chassis. I tried running it without the capacitor and it was no
different. I tried switching the speakers connected to the amps but
it was no different. I tried praying to practically every diety from
Zeus to Jesus to Haile Selasse but it was no different.

I've been trying to figure this out for a few weeks. Pretty soon I'm
going to stuff a rag in the gas tank and light it all on fire.

Please help me.

------------- -----------------
| | | |
| battery | | head unit |
| | | |
----------- --------------
| |
| + |
| | 1 set
| | of RCA
| | output
| GND | jacks
| | |
-------------- |
| capacitor | |
-------------- |
| |
| + | GND
| V |
--------------- -----------------
| distribution | + | |
| block |----------| amp 1 |
--------------- | RF 200.4 |
| \ | (bridged) |
|+ \+ | |
| \ -------------------
| \ |
| GND \ |
| | \ | audio
---------------- ----------------- | pass
| | | | | thru
| amp 3 | | amp 2 | |
| RF 600.4 | | RF 400.4 | |
| | | | <----|
--------------- ----------------
| |
| |
| |
| audio pass thru |
|-----------------------------|

[Christopher \Torroid\ Ott]

I'm a bit confused regarding how your RCA cables are routed. Do the amps
have a a "pass-thru" where they can come out and drive the next amp in the
chain? Is the noise coming from all the amps, or just the one hooked up to
the RCA's?

Generally speaking, if the power and ground are good, and the speakers are
wired up correctly, you should start by unplugging all the RCA's and
systematically going through the inputs. If you have shorting RCA plugs (for
troubleshooting) place them on the inputs to all the amps. If you get noise
with shorting plugs in place, either the amp is damaged or the power supply
(or power source) is bad. Then one at a time begin replacing the shorting
plugs with a real signal.

It kinda sounds like you have an amp with an open input which is picking up
noise from it's own switching power supply.

Chris



> wrote in message
...
>I have three amps in my Jeep. A month ago, all three were working.
> Things were good.
>
> Then I decided to make the system better by building a little cabinet
> for the three amps, because I am an idiot and I can't just be happy
> with any system, ever. Now I can't get them to work again.
>
> THE PROBLEM: I can hook up any one amp, and it works beautifully with
> any speakers. Once I hook up the second amp, loud constant noise
> comes through the speakers.
>
> THE ATTEMPTED SOLUTIONS: I have replaced all of the ground wires but
> I don't think they're a problem anyway since any amp works with any
> set of wires. They're all grounded to separate points on the
> chassis. I tried running it without the capacitor and it was no
> different. I tried switching the speakers connected to the amps but
> it was no different. I tried praying to practically every diety from
> Zeus to Jesus to Haile Selasse but it was no different.
>
> I've been trying to figure this out for a few weeks. Pretty soon I'm
> going to stuff a rag in the gas tank and light it all on fire.
>
> Please help me.
>
> ------------- -----------------
> | | | |
> | battery | | head unit |
> | | | |
> ----------- --------------
> | |
> | + |
> | | 1 set
> | | of RCA
> | | output
> | GND | jacks
> | | |
> -------------- |
> | capacitor | |
> -------------- |
> | |
> | + | GND
> | V |
> --------------- -----------------
> | distribution | + | |
> | block |----------| amp 1 |
> --------------- | RF 200.4 |
> | \ | (bridged) |
> |+ \+ | |
> | \ -------------------
> | \ |
> | GND \ |
> | | \ | audio
> ---------------- ----------------- | pass
> | | | | | thru
> | amp 3 | | amp 2 | |
> | RF 600.4 | | RF 400.4 | |
> | | | | <----|
> --------------- ----------------
> | |
> | |
> | |
> | audio pass thru |
> |-----------------------------|

[Mister.Lull]

On Nov 29, 5:37 pm, "Christopher \"Torroid\" Ott" <spamtrap at
ottelectronics dot com> wrote:
> I'm a bit confused regarding how your RCA cables are routed. Do the amps
> have a a "pass-thru" where they can come out and drive the next amp in the
> chain? Is the noise coming from all the amps, or just the one hooked up to
> the RCA's?
>
> Generally speaking, if the power and ground are good, and the speakers are
> wired up correctly, you should start by unplugging all the RCA's and
> systematically going through the inputs. If you have shorting RCA plugs (for
> troubleshooting) place them on the inputs to all the amps. If you get noise
> with shorting plugs in place, either the amp is damaged or the power supply
> (or power source) is bad. Then one at a time begin replacing the shorting
> plugs with a real signal.
>
> It kinda sounds like you have an amp with an open input which is picking up
> noise from it's own switching power supply.
>
> Chris
>
> > wrote in message
>
> ...
>
>
>
> >I have three amps in my Jeep. A month ago, all three were working.
> > Things were good.
>
> > Then I decided to make the system better by building a little cabinet
> > for the three amps, because I am an idiot and I can't just be happy
> > with any system, ever. Now I can't get them to work again.
>
> > THE PROBLEM: I can hook up any one amp, and it works beautifully with
> > any speakers. Once I hook up the second amp, loud constant noise
> > comes through the speakers.
>
> > THE ATTEMPTED SOLUTIONS: I have replaced all of the ground wires but
> > I don't think they're a problem anyway since any amp works with any
> > set of wires. They're all grounded to separate points on the
> > chassis. I tried running it without the capacitor and it was no
> > different. I tried switching the speakers connected to the amps but
> > it was no different. I tried praying to practically every diety from
> > Zeus to Jesus to Haile Selasse but it was no different.
>
> > I've been trying to figure this out for a few weeks. Pretty soon I'm
> > going to stuff a rag in the gas tank and light it all on fire.
>
> > Please help me.
>
> > ------------- -----------------
> > | | | |
> > | battery | | head unit |
> > | | | |
> > ----------- --------------
> > | |
> > | + |
> > | | 1 set
> > | | of RCA
> > | | output
> > | GND | jacks
> > | | |
> > -------------- |
> > | capacitor | |
> > -------------- |
> > | |
> > | + | GND
> > | V |
> > --------------- -----------------
> > | distribution | + | |
> > | block |----------| amp 1 |
> > --------------- | RF 200.4 |
> > | \ | (bridged) |
> > |+ \+ | |
> > | \ -------------------
> > | \ |
> > | GND \ |
> > | | \ | audio
> > ---------------- ----------------- | pass
> > | | | | | thru
> > | amp 3 | | amp 2 | |
> > | RF 600.4 | | RF 400.4 | |
> > | | | | <----|
> > --------------- ----------------
> > | |
> > | |
> > | |
> > | audio pass thru |
> > |-----------------------------|- Hide quoted text -
>
> - Show quoted text -

I have a really simple, easy to check, theory:
How does the grounding strip look from the negative terminal of your
battery to the chassis?

Just another little something you might want to check...

~Mister.Lull

[Matt Ion]

wrote:
> I have three amps in my Jeep. A month ago, all three were working.
> Things were good.
>
> Then I decided to make the system better by building a little cabinet
> for the three amps, because I am an idiot and I can't just be happy
> with any system, ever. Now I can't get them to work again.

Well, assuming you have the amps mounted to wood or some other
non-conductive material now, the main thing that's changed then, is
probably that the amp chassis themselves are no longer grounded to the
body of the car, which they would have been when they were screwed down
before.

> THE PROBLEM: I can hook up any one amp, and it works beautifully with
> any speakers. Once I hook up the second amp, loud constant noise
> comes through the speakers.

That just screams "ground loop". See previous paragraph regarding how
grounding has changed.

> THE ATTEMPTED SOLUTIONS: I have replaced all of the ground wires but
> I don't think they're a problem anyway since any amp works with any
> set of wires. They're all grounded to separate points on the
> chassis.

Try grounding them all to the same point, ideally with the same length
wires.

> I tried running it without the capacitor and it was no
> different. I tried switching the speakers connected to the amps but
> it was no different. I tried praying to practically every diety from
> Zeus to Jesus to Haile Selasse but it was no different.

There's your problem: you have to sacrifice a goldfish to Dave Rivera.
(If you've been living under a car audio rock and don't know who that
is, check here: http://www.termpro.com/showcars/terminator/ca1096.html
(scroll down to "Fishtank Toyota" near the bottom)).