In reference to replacing the factory Bose amp, can someone tell me why people here are using a device that is designed to take a speaker-level signal and convert it to line-level signal, and installing it on the line-level outputs of the HU? What are they "converting"? Line-level to line-level? Why can't you just connect the factory line-level signal to the replacement amp?

 

An LOC is not needed to run the Bose line level signal into another amp. Just splice an RCA end onto the Bose HU output wires and plug it into your new amp.

 

Some LOCs have pre outs for amps

This saves alot of money buy not having to buy a dask kit and an aftermakret radio....which can easily add up to $1000+

Also the BOSE HU only puts out like 0.2 volts , so you would have to turn your gain on your amp really high which could add alot of noise

 

Could you be clearer in your explanation?

A LOC takes speaker-level (high-power) signals and converts them to low-level (low-power) signals on RCA plugs (for input to amps/processors, etc.). They are converting high-power to low-power. BUT, people on this forum are suggesting using this device to convert low-level signals from the HU to what? More low-level signals? I don't get it. Is it doing something else to the low-level signals? These units are passive, so it isn't amplifying the signal. Color me confused

 

what an LOC does it translate the signal coming from the head unit and to the lowlevel signal most amps can work with.
some amps have a built in "high level input" which is the same as an LOC
you can think of it this way - it's the interpreter between the german speaking guy and the english speaking guy
Without the translator in the middle nothing would get done

 

JL amps are a popular option for folks on the site for this very reason. Splice RCAs into the HU outputs and adjust the sensitivity on the amp, mission accomplished. This is especially effective when adding a sub. When you add other speakers you really want some signal processing to give you flexibility over EQ and time alignment/phase.

 

Thanks. but that really isn't answering my question. I understand what a LOC does and why you'd use it when a HU only has speaker level outputs. Why are people using LOC's on low-level outputs on the G35's Bose HU? What is it doing to the already low-level signal?

 

Sorry man I didn't know exactly what you were having trouble understanding
what people are doing - which *in theory* shouldn't work as well - is take the signal from the HU after it goes into the amp.
They should be tapping off the wires BEFORE the amp - which would be a high level.
But it's working both ways so it doesn't matter really.
The LOC is still necessary to plug into most amps RCA inputs - which is another reason ppl are getting them.

 

Why is it necessary? That is my question. Why are people here using a LOC on low-level signals. I've never heard of that before.

BTW, I successfully connected the low-level signal (before it entered the Bose amp) to an Alpine M650/Alpine Type R 10", last night in my buddy's '03 coupe. I didn't use a LOC. I can't find any documentation that says that the M650 accepts differential balanced inputs.

 

you're not quite following me...
if an AMP DOES NOT have high level inputs (accept speaker wire outputs as signal) then you have to get something to translate the signal
if your AMP DOES have high level inputs you don't need an LOC

 

Alpine and JL are the only ones that I'm aware of that have the circuitry that will allow whatever signal coming in to be the same and consistent as they have a built in line driver. it's pretty impressive. It's really eliminated the need for a high pre-out voltage deck

 

We are going in circles. It looks like we agree on what a LOC is and what it is used for. For the sake of this conversation, forget high-level signals even exist. My question since the beginning is why people on this board are advising to use a LOC on the low-level signals from the Bose HU to their subwoofer amp. This is what I don't understand. I didn't use one last night and eveything went fine. At this point, I'm just curious since it's not an issue for me anymore.

 

Just installed a PDX-5 amp using stock bose HU. I used a LOC and the clarity was crap. Spliced into RCA to give that a try and it sounds 100% better than through the LOC. Just got my DD kit so now I will be installing a new head unit...

 

The signal from the Bose HU is low level before it enters the Bose amp. This is how the Bose HU differs from the non-Bose HU, which outputs speaker level voltage.

In my sedan, I ran the low level signal into my Xtant amp with just RCA ends added to the pre-Bose HU output.

 

The Bose head unit actually puts out about 2 volts, when you use a standard 10:1 non adjustable LOC you will have about .2 volts

Some amps will just NOT WORK without an LOC. Even though most LOC's are not advertised as specifically serving the purpose, generally amps which do not accept balanced inputs will work with a normal el-cheapo LOC in place. If you install the amp, splice in RCA's and find that there is no real output but rather a loud buzzing, the LOC has remedied that in every case i have come across in our cars