Preout help

[alpha_helix]

Hey,

I have just installed new headunit (Pioneer DEH-3900MP), 4 channel amp (JBL GTO75.4) , components (Infinity 5010cs) and sub (JBL GTO1260B) and I have a question about the RCA cables.

The amp has a separate input for front and rear channels (i.e. 2 sets of RCA cables needed) however my headunit only has one preout.

My question is whether i can split the preout at the headunit with an adaptor or split it just before it enters the amp? Will this result in decent quality or will it be rubbish?

Also the amp has an aux output for connecting another amp; at the moment I have another short RCA cable running from this output into the other RCA input on the amp, this works however will it be providing a bad signal? Or should it be okay?

Thanks,

Matt

 

[Laura]

no you need multiple pre outs

 

[BrianR]

Matt, According to this, it only has one pre-out connection.
http://www.pioneer.eu/eur/products/DEH-3900MP/print.html

You could use both channels of your amp by inserting a line level balance/fader control between the h/u and the amp.

Or you could use the set to drive the front speakers,one channel of your amp to drive the rear speakers and the other channel to drive a sub-woofer by inserting a suitable EQ or filter, in between.

Edit, I just looked at the amp spec, and it will take inputs up to 6.5v so you could use a speaker to line level adaptor from the front output of your h/u and connect up the amp as a 4 channel device, it would also be the cheapest solution.

 

[alpha_helix]

Thanks for the quick replies. I'm thinking that I might be better off buying a new HU with 2 preouts by the sounds of it. Any recommendations for a headunit with 2 preouts that is around £100 or so?

Would it not work to just use 2 y-splitters to split the one preout into two separate ones? (I'm guessing that this wouldn't work properly as the same frequencies would be sent to both channels?)

Thanks,

Matt

 

[BrianR]

The Y splitters will work but you wont be able to control the output to get the correct F/R balance (or fade)

Your H/U will work as a 4 channel one if you use the line level adaptor for the front and the straight RCA output for the rear. And the H/U will control the fade correctly.

 

[alpha_helix]

Thanks Brian, I will try using the line level adaptor as that is preferable to buying a new HU since I only bought this one 3 days ago!

 

[BrianR]

This is what it looks like,

 

[ChrisPearson]

i used the adaptor on my mates 6 channel amp. does anyone know about amping front speakers and how to get the wire to them? without drilling holes?

 

[alpha_helix]

This is what it looks like,

View attachment 17275

cheers, looking at that i'm sure that the JBL amp actually comes with something similar, except it has a block connector (it says that its a high level input in the manual).

 

[alpha_helix]

i used the adaptor on my mates 6 channel amp. does anyone know about amping front speakers and how to get the wire to them? without drilling holes?

I just spent the best part of all day yesterday trying to figure out the best way; it was a pain in the ass! I ended up just pulling the rubber snake thing off the door and drilling a hole through part of the connector that didnt have a wire in it. this then allowed me to feed the speaker cable through. I wanted to do it without drilling but couldnt find a way. I only ended up drilling the plastic connector though and not the door (I didnt want to have to drill through the door.) It may be easier to just splice into the existing speaker wires but I read on here that they were only good for about 50-60W RMS .

 

[ChrisPearson]

how could you see which part of the plastic connector did not have wires in it. and did you have to take the door off to get the drill at the correct angle?

 

[BrianR]

This is what it looks like,

View attachment 17275

cheers, looking at that i'm sure that the JBL amp actually comes with something similar, except it has a block connector (it says that its a high level input in the manual).

Thats the same thing, read the manual is all I can suggest.

 

[BrianR]

i used the adaptor on my mates 6 channel amp. does anyone know about amping front speakers and how to get the wire to them? without drilling holes?

I just spent the best part of all day yesterday trying to figure out the best way; it was a pain in the ass! I ended up just pulling the rubber snake thing off the door and drilling a hole through part of the connector that didnt have a wire in it. this then allowed me to feed the speaker cable through. I wanted to do it without drilling but couldnt find a way. I only ended up drilling the plastic connector though and not the door (I didnt want to have to drill through the door.) It may be easier to just splice into the existing speaker wires but I read on here that they were only good for about 50-60W RMS .

Thats exactly the right way to do it, well worked out !!

 

[ChrisPearson]

how can you tell which part of the plastic clip does not have existing wires going through it? the door is in the way!

 

[alpha_helix]

Once you have pulled the rubber snake off you can see where there are gaps in the block for that part of the connector. The other bit that is fixed to the door plate can be removed by unscrewing the 2 screws that are about 1cm above and below where the block comes through the door plate. when you remove these if you just stick your hand in the footwell where the wires lead into the block and pull, then it will come away and you will be able to see the connections that are not used on the block.

Thats actually quite hard to explain! but I think that about covers it.

Matt

 

[ChrisPearson]

cheers i think i know what you mean. are they star head screws? and difficult to get at?

 

[alpha_helix]

yeah they are T20's if i remember rightly and are a bugger to get to, I used some right angled torx drivers to get them out but i think u could use a normal torx driver you would just have to angle it slightly to reach the screws.

 

[BrianR]

yeah they are T20's if i remember rightly and are a bugger to get to, I used some right angled torx drivers to get them out but i think u could use a normal torx driver you would just have to angle it slightly to reach the screws.

Torex !

 

[ChrisPearson]

ok thanks

 

[joel_b]

Nooope

 

[alpha_helix]

torex?