broohaha

I'm putting in a replacement for the stock system, and I'm not sure what the best way is to run my lines off the HU. The Amp can handle either line level or high level inputs. Is there any benefit to using the RCA (line level) outputs?

My set-up (or soon to be as it's in the mail):
Kappa Perfect 6.1s up front
US Acoustics 2100 - 2 channel specifically to drive the Perfects
Basslink (self amp'd running off the HU)
Alpine 9831 HU
Keeping the stock rears hooked up for filler, but may just fade them out.

So obviously, I have to power the rears with the high level rear outputs from the HU. But I wasn't sure what to feed the Amp (for the fronts) with: high level or the RCA lines. If it makes no difference, then I can just run all 4 'speaker' or 'high level' outputs from the HU to the amp and the stock speakers.

I wasn't sure if line level leads are better quality or not. (I suppose it depends on the amp in the HU.) The other issue, is I'm not even sure if the HU will put out to both the high and line level outputs at the same time. (I do know that can shut off the internal amp, I'm just not sure if the line levels are cut when you have the internal amp on.)

One last Q: In the Amp manual, it says if I'm going to use High level inputs, then I have run a separate ground (think of it as a combined (-) line for both left and right) to the same point that the HU uses for ground. Anybody know why? Or what will happen if I use the ground that the Amp/Basslink is hooked up to...?

Hopefully this makes at least a little sense to someone. I'm pretty much a noob.

islandsnow

iTrader: (6)

I would use RCA wherever you can and Line Level if you have no choice. RCA is just the signal, line has the amplified signal and has to go through the line level filters to get the signal therefore more processing and less clarity i would think. But then again i do have a line level to RCA adapter in my other car that works fairly well, but i would still use RCA first if you can, it's also easier to hook up(at least to me). As far as the grounding goes, i'm not sure why you would have to do this, extra noise maybe? I use a line level converter that if it's grounded does not go back to the HU ground, so i'm not sure if this is needed but try it the easier way first and if you get hum or noise, then do it like they say. And both line and RCA should work at the same time, i haven't seen any head unit that turns one off while the other is working.

good luck,

MSGarrett1

The problem you may run into is noise . . . particularly alternator whine. The best solution . . . replace the stock headunit. Choose an aftermarket one with high volt (4 - 5 Volt) preamp RCA outputs, and choose a quality RCA cable. This gives you the least chance for noise.

Next best choice . . . get a high-level (speaker level) to RCA converter and a set of quality RCA cables. Then, run the speaker wire directly to the amp using the high-level (speaker level) amp inputs and listen. Then, run the speaker wire to the converter and the RCAs to the amp via the RCA inputs and listen. Then choose whichever way sounds best to you. At worst, you are out the cost of the converter and the RCA cables, if you think it sounds best using the speaker level inputs. Which is better will depend greatly on how your amp is built, the quality of the converter and RCA cables, and where you run your signal wires (run them as far away from your amp's power and ground wires as possible.) My guess is, it will sound better with the RCA converter.

broohaha

OK, so based on the two recommendations above I will:

1. Connect the Rears using the HU normal speaker outputs (high level)
2. Connect the amp using the HU's RCA (line level), which will ultimately power my fronts.
3. Use the HU's sub RCA connection for the basslink.

I guess I had assumed that there may be some kind of issue for using just half of the the speaker high level outputs.

Thanks for everyone's input.

MSGarrett1

Oops . . . didn't see the aftermarket Alpine HU in your original thread. Yes you could use the speaker outputs to the rear speakers . . . BUT the problem is that they are 12 Ohm speakers, not 4 ohm like the rest of the industry . . . they will be very quiet or not play at all. Worst case scenario . . . you fry your Alpine's internal amplifier as it tries to play through these 12 Ohm Clarion stock rear speakers. I seriously doubt this will happen, though. I've run a headunit's internal amp to high resistance speakers before without problem . . . they just play quieter than they would have if they were the normal 4 ohms. However, if you ever try to run a headunit's internal amp to power a lower than normal load . . . say 2 or 1 ohm . . . headunit WILL FRY as it draws too much current!

If the Alpine has two sets of RCA outputs, you're all set, one set to the amp for the front speakers, and the other to the Basslink.