low level inputs on a 4ch!
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=21831
Printed Date: June 10, 2024 at 1:25 PM
Topic: low level inputs on a 4ch!
Posted By: TheevesLLC
Subject: low level inputs on a 4ch!
Date Posted: November 23, 2003 at 2:30 PM
the car is a 97 mazda protege. i am installing a power acoustik ov4600 amp and spx 280w 6x9 and spx 200w 6.25" to that amp. the owner still wants to use the factory head and cd accessory, which is fine however it has no highlevel (RCA) output, nor does it have an amp remote lead. i have channeled all the speakers from the head to the low-level input plug on the amp, and tapped the 12v assy lead for the amp remote lead. at first, this worked fine, sounded decent, so i began to fuxor with the xovers and gain. now the amp cannot maintain power, it will show the protect led for a second, then cut on, then jump back to protect, providing about 1-2seconds of music per cycle. my first thought was power/ground, however i have thoroughly checked all power/ground connections, to no avail. my second thought is that perhaps i should replace the factory radio fuse with one of higher amp rating, but if that's the problem shouldn't the fuse just blow? i've never done a low level input amp install before, and this isn't proving a victorious first! any ideas? thanks connor
Replies:
Posted By: DYohn
Date Posted: November 23, 2003 at 4:36 PM
If you're using the speaker feeds from the factory head unit to the amp, that is the high level inputs. Your gain is much too high on the amp. It has nothing to do with fuses. Turn the amp gain all teh way down, set the factory head unit to about 3/4 volume, then turn the gains up slowly until you can detect distortion, then back them off until it is clear.
Posted By: TheevesLLC
Date Posted: November 23, 2003 at 6:08 PM
high level inputs, my mistake... it is not the gain on the amp, i have turned the gains all the way down, i have tried multiple crossover configurations which would require the least power too. there is no distortion when the amp turns on, it plays loud and clear, and then cuts off. thanks anyway, anybody else have any ideas? connor
Posted By: DYohn
Date Posted: November 23, 2003 at 6:38 PM
Could be a defective amp. I've never had much luck with Power Acoustic.
Posted By: TheevesLLC
Date Posted: November 23, 2003 at 6:51 PM
hmm. i sell many gothic series power acoustik amplifiers, i've not had one returned yet. i have tried the amp in my car, it works properly there. i suppose i'll just redo all of my connections and cross my fingers
Posted By: DYohn
Date Posted: November 24, 2003 at 8:37 AM
If you're sure the amp is OK, try disconnecting the speakers and hooking everything up to check that the speaker load is not too low an impedence. If the amp is stable with no load on it, try connecting the speakers on at a time as you may have a bad speaker or a bad speaker wire. Check all your connections and be sure there are no stray wires that can short to ground, make sure the head unit is not putting out too much power for the amp's high level inputs, make sure your xover gains are not set too high. In fact, how are you using high level signals from your HU and using Xovers? Or do you mean the Xovers built into the amp?
Posted By: TheevesLLC
Date Posted: November 24, 2003 at 8:23 PM
using the amps internal xovers. although i could have some 80s highlevel crap. the first time the amp went berserk, i tried disconnecting the speakers, and it still wasn't happening. i'm almost positive the output of the head is 15x4, and i have checked the wiring. i'm just going to yank power/grounds and reinstall them. thanks for your help Connor
Posted By: auex
Date Posted: November 24, 2003 at 9:44 PM
Are you using a line output converter ( high to low coverter, speaker to rca), or did you just wire rca ends on to the speaker wires? If you just wired rca ends onto the speaker wires that is your problem.
-------------
Certified Security Specialist
Always check info with a digital multimeter.
I promise to be good.
Tell Darwin I sent you.
I've been sick lately, sorry I won't be on much.
Posted By: TheevesLLC
Date Posted: November 25, 2003 at 12:06 AM
Posted By: auex
Date Posted: November 25, 2003 at 8:41 AM
TheevesLLC wrote:
i have channeled all the speakers from the head to the low-level input plug on the amp, and tapped the 12v assy lead for the amp remote lead.
i've never done a low level input amp install before.
It says nothing about how you connected the speaker level(high) to the amps low level inputs. So please re-read your first post. ------------- Certified Security Specialist
Always check info with a digital multimeter.
I promise to be good.
Tell Darwin I sent you.
I've been sick lately, sorry I won't be on much.
Posted By: Stevolon
Date Posted: November 25, 2003 at 2:45 PM
TheevesLLC, try getting a known source of signal ie a deck you got kicking around and wire it for pwer and ground right at the amp. run the rca pre-outs from this deck into the amp. and see if it works. You normaly cannot hook up a highlevel output directly to the lowlevel input of your amp. the impedence is probaly too low for the input of your amp. So try this and if it works just get a decent line level adapter and pray you dont get engine whine
-------------
Steve@A.E.S
Posted By: TheevesLLC
Date Posted: November 25, 2003 at 8:19 PM
if any of you have read the followups by DYohn, you'd see that i was mistaken on naming the hi/lo inputs. if you don't feel like reading up, here: the speaker wires coming out of the deck, go into the plug on the amp. i am using the highlevel output of the head, and the highlevel input plug on the amplifier. just like it's meant to be.
i'm not using any line converter, or any of that. the impedance is matched. anyway, i'm going to give it another whack tomorrow, so wish me luck! thanks everybody
Posted By: TheevesLLC
Date Posted: November 27, 2003 at 7:27 PM
SUCCESS!!!! the amplifier is working perfectly now, minimal distortion, accurate xovers... however i still have no idea what the problem was. i put in a new amp, it worked. put the PA back in, and reran the speaker wires. 3 channels would sort of work, and when i hooked up 4 it would die. it really seemed impedance related, but my colleague, majoring in math/physics, did the math, and shrugged, said it should work. i know have the amp running with the FL and FR channels switched. if i change them, the amp stops working. i tried and tried to figure it out, but there isn't much consistency to it, so i found a working configuration, and called it a day. i am never using highlevel inputs again.
Posted By: DYohn
Date Posted: November 27, 2003 at 8:29 PM
This is a long shot, but it COULD be that the speaker leads from your head unit are using a common ground and negative lead, and that is throwing off the input loading on your amp... or it could simply be the hi to low level transformers inside the amp are bad. Whatever the case, congrats on getting it to work, and next time you have to use hi level signals to keep a factory head unit, I bet I hear an LOC calling your name!
|