New HU with Moons and tunes amp

splashd · Post by **splashd** » Tue Dec 02, 2003 10:45 pm

WHen I install my new HU, it is already a 4X50. How do I connect to the 6 speakers--via the existing under seat amp, or direct from the stereo?

ragingfish · Post by **ragingfish** » Tue Dec 02, 2003 11:38 pm

I installed a 4x50 HU, just connected it direct to the existing wire harness, which routes the signal through the M&T amp.

Sub-Vibe-R · Post by **Sub-Vibe-R** » Tue Dec 02, 2003 11:41 pm

The best way to do it and avoid distortion and bad sound is to use the pre-amp output of your new HU.Add some RCA jack to the stock wiring harness of the Vibe and hook them to the RCA jack of your HU. That way, you will send a 0-2v signal (or 0-4v depending of you HU) to the M&T amp, exactly like the M&T stock HU.

TheDude · Post by **TheDude** » Wed Dec 03, 2003 1:23 am

usually on the wiring harness for the car, i belive ours uses a 70-2003 metra...and the harness for your aftermarket HU, it has a blue or a blue with white wire which is the remote wire for your amp...just hook that up and it'll turn on the amp

splashd · Post by **splashd** » Wed Dec 03, 2003 1:43 am

OK forgive my ignorance. two questions:when you say hook up the remote wire to power on amp, what am I hooking the wire up to? Power?Second, wiring in the RCA plugs to harness; is it done center positive or center negative?thanks

TheDude · Post by **TheDude** » Wed Dec 03, 2003 1:52 am

the remote wire is on both harnesses, so just hook them up, but its pretty much another switch power, only on when the HU is on

Sub-Vibe-R · Post by **Sub-Vibe-R** » Wed Dec 03, 2003 3:27 am

Quote, originally posted by splashd Â»Second, wiring in the RCA plugs to harness; is it done center positive or center negative?thanksCenter positive...Just follow the metra wiring harness, you cannot go wrong.

ragingfish · Post by **ragingfish** » Wed Dec 03, 2003 2:01 pm

Quote, originally posted by splashd Â»when you say hook up the remote wire to power on amp, what am I hooking the wire up to? Power?thanksOn the harness IN the car, there is one pin that has two thin black wires coming out of it. I believe it is in the bottom row. Pin 15 if I recall correctly. Anyway, one of those two wires is the remote signal for the amp to turn on. You have to tap into it, and connect it to the blue/white wire on the NEW radio harness, usually identified as remote signal or something. This lets the HU turn on the amp.

dsegundo · Post by **dsegundo** » Fri Dec 05, 2003 3:11 pm

I've seen a h/u come with a dash kit and wiring harness....But I just recently saw a wiring harness to use a std. amp w/ a new h/u....what is that and do I need one?

ragingfish · Post by **ragingfish** » Fri Dec 05, 2003 3:13 pm

I'm not sure I understand what you mean?

splashd · Post by **splashd** » Fri Dec 05, 2003 11:38 pm

Tjh answer to my problems is: Wal-mart, belienve it or not.WHen I hooled the pre-outs from my Pioneer DEHP550MP to the amp I got a pop--likely a power spike that got amped...I bought a Scosche FAI3 for $17 that let me hook my HY speaker out firectly to my GM harness that feeds the amp. Well worth it.

ragingfish · Post by **ragingfish** » Wed Dec 17, 2003 3:38 pm

splash:That walmart harness lets you use RCA outpus on a HU for the speaker signal, instead of the tradtionl harness?I thought my radio was defective cause that white noise i used to complain about got so much worse when i installed this HU. A guy at a stereo repair shop said it could be because i'm using amplified outputs, and then amplifyingit AGAIN when it hits the M&T amp. He said I shoudl use the RCA low level output, and that should fix the problem. BUt I want a harness prewired, don't wanna have to try to make it myself.

Savageone79 · Post by **Savageone79** » Sun Sep 26, 2004 2:58 pm

I just got an 05 with moons and toons so what exactly is decided as the best way to hook a new HU into your moons and toons package. I am having a local place install it but what should I tell them and are there any extra parts I need? Thanks!

ragingfish · Post by **ragingfish** » Sun Sep 26, 2004 3:02 pm

Two ways to do it basically.One -- bypass the amp altogether and go aftermarket. This is going to give you the best performance.Two -- keep the M&T amp, but use a line-out converter to "supress" the head unit signal. If you don't use the line-out converter, the output from the headunit, which will already be amplified, will be amplified AGAIN by the M&T amp, resulting in sound that is overamplified, distorted, and crappy.I'm using the Schosche (sp?) FAI-3 or something line out converter. Was under $15 at walmart.BTW: NO RCA LINES with the M&T amp. No one has been able to make it work.

Savageone79 · Post by **Savageone79** » Sun Sep 26, 2004 3:08 pm

Thanks! I got a JVC 50wx4 unit. Would I be better off using this directly to the speakers or going through the stock amp? Also if i bypass the amp whats the easiest way to do this and will I still be able to use all 6 speakers since the jvc only has 4 speaker output?

ragingfish · Post by **ragingfish** » Sun Sep 26, 2004 4:33 pm

Unless you plan to upgrade the speakers, i'd say keep the amp. If you're gonna upgrade the speakers down the line, you're looking at a new amp, and crossovers to power the tweeters as is.I could be wrong...*paging Jahntassa, our resident audio expert*

Jahntassa · Post by **Jahntassa** » Sun Sep 26, 2004 10:31 pm

Tough decision. I'm guessing you got something like the KDS5050 or the KDG200? Here's the thing. Both the new headunit, and the M&T amp claim to be 200w. The thing is, the M&T amp is closer to the truth. The JVC radio only puts out about 18w per channel, whereas the M&T amp puts out more like 40w. Also, unless they've changed it, I believe the M&T speakers are 2 Ohm, which will not work with the new HU.Do you have the Monsoon sub in the back, as well? If so, you definitely want to keep the factory amplifier.So, if I remember correctly, because of the M&T speakers, you cannot bypass the amplifier unless you get all-new speakers as well. For right now, your best bet is just letting them install it like any other radio. If, down the line, you want to change out the speakers, then i'd reccomend a small 4 channel amplifier to push the new speakers.If you get new speakers, it's generally agreed that you can get any pair of 6.5" speakers in the rear doors, and get a better "component" set for the front. The component set is the one that comes with the midrange, tweeter, and crossover.Hope this helps, but feel free to ask/debate any of this!

Savageone79 · Post by **Savageone79** » Sun Sep 26, 2004 11:19 pm

Thanks that helps a lot! I got the KD-LH300. I don't know if the vibe I am getting has the sub or not? It is an 05 with M&T.. is the sub a standard part of that or no?

nismo · Post by **nismo** » Mon Sep 27, 2004 12:10 am

Honestly. If you're gonna change your HU, you SHOULD change your speakers at the same time. Because of the fact that the stock speakers are running at 2 ohms and most aftermarket HU's run at 4 ohms. So, if you start using the HU after the install, the radio WILL heat up. Which isn't a good thing. So, I would recommend changing your speakers at the same time. Inder

Savageone79 · Post by **Savageone79** » Mon Sep 27, 2004 12:13 am

If it's going through the factory amp does it matter?

nismo · Post by **nismo** » Mon Sep 27, 2004 12:22 am

I bypassed mine, so, if anyone wants it, $20+shipping.

Jahntassa · Post by **Jahntassa** » Mon Sep 27, 2004 4:38 am

The factory amp acts as a barrier between the HU and the speakers. The amp creates a 4 Ohm load going to the HU. You won't have a problem there.AFAIK, the 05 M&T comes with a Sub, which may or may not work after you change out the radio.

lazytiger · Post by **lazytiger** » Tue Sep 28, 2004 1:51 am

If you want to bypass the amp, that can be done fairly easily. Check out these prior threads of mine:Bypassing the Moon & Tunes ampNewbie self-install - please help.However, as was stated already, if you want to bypass the amp you definitely need to replace all the speakers as well because of the 4/2 ohm discrepancy. It's claimed that the circuitry in newer head units will prevent it from overheating; still, it's not a good idea.The much easier and cheaper solution (keeping the stock speakers and amp) would be to get the Scosche SLC-4 or FAI-3A (same thing, different part #s). See if you're happy with that first. If not, you're only out about $15, and then you can move on to the more involved installation.

Savageone79 · Post by **Savageone79** » Tue Sep 28, 2004 6:24 am

Here is a pic of the Scosche I found at walkmart.. not sure what the -3a means but will this do the trick? I am having a place install my new HU so what instructions do I need to give them?

Attached files

lazytiger · Post by **lazytiger** » Tue Sep 28, 2004 6:51 am

Quote, originally posted by Savageone79 Â»I am having a place install my new HU so what instructions do I need to give them?They ought to be able to figure it out if they're worth their salt. But here's the gist of it: The Vibe has an external amp. Double-amping the signal (once from the head unit, then again by the external amp) is undesirable. Therefore, it's best to send line level signals to the amp. Unfortunately, the amp does not have RCA inputs, so the only way to get a line level signal from the head unit to the amp is to use the speaker level outputs from the head unit, run them through Scosche FAI-3A, and then on to the amp.I have not actually used the Scosche, but others here have. Hopefully they'll chime in. But I assume the best place for the FAI-3A is in the dash somewhere, right behind the head unit.

Jahntassa · Post by **Jahntassa** » Tue Sep 28, 2004 10:37 am

If Mike chimes in, he had the schosche. If I remember correctly, it only added to the problem. You'd be better off just connecting the amp straight-up, but wait for a M&T'er to respond.

ragingfish · Post by **ragingfish** » Tue Sep 28, 2004 12:07 pm

Quote, originally posted by Jahntassa Â»If Mike chimes in, he had the schosche. If I remember correctly, it only added to the problem. You'd be better off just connecting the amp straight-up, but wait for a M&T'er to respond.'Actually, my problems developed when I tried to use the RCA outs on my HU to go to M&T. The schosche works great, I'm still using it...

Jahntassa · Post by **Jahntassa** » Wed Sep 29, 2004 1:50 am

Ah-ha..I sit corrected then!

Savageone79 · Post by **Savageone79** » Wed Oct 06, 2004 3:06 am

Well they installed it and it is all fine. Used the schosche and it worked fine. Sounds great and no problems. Sub and all speakers work fine!

New HU with Moons and tunes amp

New HU with Moons and tunes amp

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