strange input/turn on problem

[benlebow]

Nope, amp comes on, no protection light, if I leave the RCAs unplugged when I start the vehicle, everything plays fine.

 

[Perry Babin]

Do you have one of the speaker wires from the deck connected to the RCA shield that you're grounding?

 

[benlebow]

Umm...yes. Yes I did.

 

[Perry Babin]

That would do it. You will only use the positive speaker wire to feed the LOC resistors. The other end of the resistors goes to shield ground which connects to the chassis of the head unit.

 

[benlebow]

Thanks again, Perry. I'll do that in the morning.

Ben

 

[benlebow]

Thanks again, Perry. My homedone LOC works like a charm.

Next problem: Now I have a very quiet alternator noise playing through my midrange speakers. Must be some sort of ground loop. But everything turns on now!

Ben

 

[benlebow]

Sorry to drag this out, but if I rebuilt my LOC to make R1 higher resistance than the highest input impedance it faces, would that lift my ground loop?

Ben

 

[Perry Babin]

Does the noise go away if you only have the LOC plugged into the amp driving your mids (no other amps connected to the signal line)?

 

[benlebow]

Nope. Right now I have the LOC feeding my midrange amp (Kicker ix254 bridged into 8ohm), with the lineout of the Kicker feeding the Pyle I repaired. Tweeters are running on deck power, and have no alt noise. I disconnected signal from the Pyle and the whine still comes through the mids. I can't detect any whine through the sub that is connected to the Pyle.

Ben

PS I have a proper LOC and line driver coming in the mail from a friend, this should eliminate the problem, no?

 

[Perry Babin]

Try connecting the pyle to the mids to see if the noise is being produced by the head unit. If there is no noise, reconnect the kicker and reduce the gain. If the noise is reduced, try reducing the ratio of the resistors in the LOC from 10:1 to 3:1 (3.3k:1k approximately). The lower ratio will produce more output voltage so you can use the lower gain setting.

 

[benlebow]

Thanks Perry. I'll try that while I wait on mail.

Ben