Help! Aftermarket Amp and Sub Problems

[jsimon63]

My son and I have installed a Sony amp and sub in our 2004 Pontiac Vibe w/ Moon and Tunes...(6 disc w/ 200 watt amp). Anyways the problems... They are very odd to say the least, 1) When the car is turned on and the sub is already hooked into the amp, there is no sound from ANY speaker in the car, including the sub. However, if the car is already on, then the sub is connected to the amp by me, all is well. 2) There also seems to be some really nasty engine noise coming through the audio signal to the amp. When the stereo is off, but the amp(s) remain on, there is some nasty humming corresponding with the engine noise. Pretty sure its engine noise, only happens when the engine is on. Doesn't happen when just accessories are on. The factory harness at the stereo is spliced and runs back to the amp going in as a high level input. I think the splicing is most of the trouble. But wiring diagrams assure me that the right wires are spliced (rear speakers) for the amp's audio signal. The amp turns on and off just fine, so the remote wire and signal aren't an issue. I believe its just a signal issue of some type. Is it recommended to splice at the factory amp or at the radio?Thanks in advance!

[scherry2]

jahntassa replied to me along time ago on this same problem. http://forums.genvibe.com/zerothread?id=13072 you need a line output converter to convert the signal you're picking up to ACTUAL line level. What's coming from the radio is NOT line level, and you're probably damaging either the radio, or either amplifier each time you turn it on. If you want to wire it with the speaker wiring, you need to use the hi-level inputs on the amplifier.

[Sublimewind]

Quote, originally posted by scherry2 »jahntassa replied to me along time ago on this same problem. http://forums.genvibe.com/zerothread?id=13072 you need a line output converter to convert the signal you're picking up to ACTUAL line level. What's coming from the radio is NOT line level, and you're probably damaging either the radio, or either amplifier each time you turn it on. If you want to wire it with the speaker wiring, you need to use the hi-level inputs on the amplifier. He mentioned using the "high level" inputs on the amp so that "shouldn't" be the problem, although I've personally never liked high level inputs on any amp. If you did decide to go the LOC (line output converter) route (which is the better idea) consider Navone Engineering http://www.autosound2000.com/ as your source for the LOC... Dave Navone has been in the car audio world since the beginning and makes excellent products. You'll need some at least decent RCA cables also. The noise issue and the no sound issue could both be a bad ground somewhere in the system. Where did you ground the amp at specifically? I don't know if i understand these statements.Quote »When the stereo is off, but the amp(s) remain on, there is some nasty humming corresponding with the engine noise. Pretty sure its engine noise, only happens when the engine is on. Doesn't happen when just accessories are on. Quote »The amp turns on and off just fine, so the remote wire and signal aren't an issue. I believe its just a signal issue of some type. The does not compute... And if you have the factory amp, you prolly want to splice the high level wires out of that rather than the HU... just spitballing that one though...

[scherry2]

I'll take a pic of mine tonight and post it. I'm sure I just jumpered into the door speaker wires after the Amp with a Line Output Converter. get some good RCA plugs with wire, I picked up mine from circuit city a while back.

[scherry2]

here are the pics I tookkind of self explainatory -------------------------------------------------------------------------------hope this helps

[jsimon63]

Scherry, Thanks for the replies and pics! I will try this and see what happens.Sublimewind, sorry for the babbling, scherry explains it better in a previous topic...."when i turn the key on everything is fine but when i start the car I don't get any sound anywhere, untill i unplug the RCA plug at the input at the sub amp and plug it back in then everything works."Thats my exact problem. I'm hoping it, and the engine noise, are just associated with the way everything is hooked up right now.My ground- Its hooked to one of the bolts that hold the back seat to the floor on the driver's side of the car.

[Sublimewind]

Did you make sure to sand/grind off the paint when you did the ground? if not, you need to and apply some dielectric grease to keep it from corroding... Hmmmm..... very strange, you get nothing, until you un-plug an RCA and then plug it back in.... lemme sleep on it... i might come up with something...

[scherry2]

let us know.

[jsimon63]

Ok, I got the line converter hooked up and everything is fine now. I don't have engine noise because I just turned down the line it was coming from...easy enough. I'm sure I just spliced the wrong wire or something, but it all works just fine now that I turned down that signal. I thought I spliced the right rear speaker, but oh well.The whole system turns on and off with no problems!Thanks alot you guys!

[scherry2]

glad to help.

[Sublimewind]

SHWEET.... rock on....BTW, did you read what i said about the dielectric grease?

[jsimon63]

Yeah, I'll probably get around to that soon..thanks for the advice!