How Do Head Unit Line-Level Outputs Work?

[TRAFFICBLOWS]

I had sent an email to Eclipse audio asking about the line-level outputs of one of their head units, and what they came back with I never heard before- thought I'd ask you guys if it makes sense.

The voltage output on the RCA’s is max 8volts. It is controlled by the volume control. For example, at 25% volume, the output is 2 volts, and at 50% is 4 volts etc.

Is this how line-level outputs normally work?? An amp I have (JBL GTH400) accepts 4V RMS and I don't want to overload it.

[Jackass-Jeff]

it's fine to have the 8V feed the 4Vinput.

Adjust the gain accordingly though. Your voltage will not reach 8V until you hit higher volumes. Your gain should be near 0 (4V) because of the level of current from the RCAs.

You're good to go! Just make sure you don't turn the volume up too high... clipping amps is bad!

[Vampire]

Yes, Eclipse is correct. The voltage output is proportional to volume. You will hit 8 volts only near max volume or put another way. The voltage will increase as the volume is increased till you hit the max volume at which the voltage will hit it's rated peak of 8 volts. As far as inputting it into an amp rated to take 4 volts max? I don't know about that. I wouldn't but that's just me and I have no data to back that up because I never thought about doing that.

[TRAFFICBLOWS]

This is what I got from JBL upon asking about feeding amp with up to 8V:

The maximum signal input voltage is 4v rms and anything above that (5v and up) stands the risk of driving the amplifier into input overload which would cause the amplifier to shut down or go into protect. Because of this I would recommend that you keep the signal gain level of the amplifier at the minimum to prevent the input from being over driven. As a side note, even if you have a 4v rms head unit you can still cause the amplifier to clip due to the signal distortion limit of the head unit itself. So it is recommended that you take the time to properly balance the amplifier input with respect to the output signal voltage of your head unit.

Sounds like the amp and h/u would not make the best match, although it seems they'd work fine up to ~50% volume.

[hari-bhari]

you could get a LOC like i did. theres a good one from navone.com and it will take your amped signal from the headunit and cut it back down so u can use the pre-amp inputs on your amp and get the cleanest sound. thats what i did with my factory headunit hooking up to my 4 channel amp and it sounds pretty good

[B_Master_Flash]

This is what I got from JBL upon asking about feeding amp with up to 8V:

Sounds like the amp and h/u would not make the best match, although it seems they'd work fine up to ~50% volume.

Everything on that H/U is ajustable. Just turn the sub out level (or which ever output you're using) down until you get the desired voltage. This is why they have controls on the H/U, if your amp is maxed out at 50% volume and you seriously dont know what to do, maybe you shouldn't be trying to tune your system by yourself.

[B_Master_Flash]

you could get a LOC like i did. theres a good one from navone.com and it will take your amped signal from the headunit and cut it back down so u can use the pre-amp inputs on your amp and get the cleanest sound. thats what i did with my factory headunit hooking up to my 4 channel amp and it sounds pretty good

No. There isn't a output converter that can touch the quality of eclipse (or any decent H/U's) preouts.