12volts on my amp's RCA inputs

[Steve]

I have an a/d/s 8 channel 830x amplifier that I've been having some
issues with. The amp will sometimes short 12v power to the RCA ground
shields. This caused my headunit's preamp to blow, of course. If I
disconnect the amp totally, I get continuity between the 12v terminal
and the RCA grounds. After opening and amp, I could see nothing
obvious. Putting things back together, I no longer had continuity, so
I hooked things back up (minus headunit) and turned the amp back on.
Within seconds, I was reading 12v on the RCA grounds again. Anyone
have any ideas where I should start looking in the amp?

[GregS]

In article <200604111241208930-drevilkep@hotmailcom>, Steve > wrote:
>I have an a/d/s 8 channel 830x amplifier that I've been having some
>issues with. The amp will sometimes short 12v power to the RCA ground
>shields. This caused my headunit's preamp to blow, of course. If I
>disconnect the amp totally, I get continuity between the 12v terminal
>and the RCA grounds. After opening and amp, I could see nothing
>obvious. Putting things back together, I no longer had continuity, so
>I hooked things back up (minus headunit) and turned the amp back on.
>Within seconds, I was reading 12v on the RCA grounds again. Anyone
>have any ideas where I should start looking in the amp?

Normally, coupling caps are the fault. I would have to check around the
circuit. I suspect even an RCA isolator would be bad, as
it might also short. The amount of shorting current could also be measured.
I would also mesure it with a meter on both conductors of
the RCA to ground. I guess we can also call these phono plugs!

greg

[Kevin McMurtrie]

In article <200604111241208930-drevilkep@hotmailcom>,
Steve > wrote:

> I have an a/d/s 8 channel 830x amplifier that I've been having some
> issues with. The amp will sometimes short 12v power to the RCA ground
> shields. This caused my headunit's preamp to blow, of course. If I
> disconnect the amp totally, I get continuity between the 12v terminal
> and the RCA grounds. After opening and amp, I could see nothing
> obvious. Putting things back together, I no longer had continuity, so
> I hooked things back up (minus headunit) and turned the amp back on.
> Within seconds, I was reading 12v on the RCA grounds again. Anyone
> have any ideas where I should start looking in the amp?

It sounds like your amp has a floating ground and an isolated power
supply. The good news is that the 12V battery power doesn't go very far
in such a design. It should be easy to trace the 12V lines to some
mechanical damage or a crushed insulator. Try wiggling the mounting
bolts on the power supply semiconductors.

[ac0j]

I have an a/d/s 8 channel 830x amplifier that I've been having some
issues with. The amp will sometimes short 12v power to the RCA ground
shields. This caused my headunit's preamp to blow, of course. If I
disconnect the amp totally, I get continuity between the 12v terminal
and the RCA grounds. After opening and amp, I could see nothing
obvious. Putting things back together, I no longer had continuity, so
I hooked things back up (minus headunit) and turned the amp back on.
Within seconds, I was reading 12v on the RCA grounds again. Anyone
have any ideas where I should start looking in the amp?


You dont have a good enough main ground at the amplifier and the amp is trying to ground through your RCA's. A disconnected or bad groud will measure 12 volts. I have seen this many many times. does your amp stay powered on when you disconnect the rca's? I bet you will read 12 volts at your ground connection as well. Make sure you have a SOLID ground connection for your amp! do you have engine noise problems off and on too???? 99% sure thats your problem!

acØj

[John Durbin]

It will also happen if the power supply rails in the amp are not
balanced properly or if any number of internal components have shorted.

JD

ac0j wrote:
> Steve Wrote:
>
>>I have an a/d/s 8 channel 830x amplifier that I've been having some
>>issues with. The amp will sometimes short 12v power to the RCA ground
>>shields. This caused my headunit's preamp to blow, of course. If I
>>disconnect the amp totally, I get continuity between the 12v terminal
>>and the RCA grounds. After opening and amp, I could see nothing
>>obvious. Putting things back together, I no longer had continuity, so
>>I hooked things back up (minus headunit) and turned the amp back on.
>>Within seconds, I was reading 12v on the RCA grounds again. Anyone
>>have any ideas where I should start looking in the amp?
>
>
>
> You dont have a good enough main ground at the amplifier and the amp is
> trying to ground through your RCA's. A disconnected or bad groud will
> measure 12 volts. I have seen this many many times. does your amp stay
> powered on when you disconnect the rca's? I bet you will read 12 volts
> at your ground connection as well. Make sure you have a SOLID ground
> connection for your amp! do you have engine noise problems off and on
> too???? 99% sure thats your problem!
>
> acØj
>
>