Best way to split RCA

[naca5]

Hi,

I'm wondering how to split RCA in the following situation:
I've a B5 crossover with two set of output: high and Low level,
For low level I've for driver to drive and I use 4 amps, hence the question.
Can I just short the two + on one end of the cable and split it on the amp board?
Or do I have to use a splitter (trnasformer or so...)

Thanks

 

[sgrossklass]

So you need to drive four power amps from one output?

That should basically work just fine with a splitter cable (or rather three, most probably), but do keep in mind:
1. The crossover output will see all 4 amplifier inputs in parallel. 20 kOhms per amplifier, for example, would mean a 5 kOhm load. It must be able to handle that easily. No load driving spec is available for the B5.
2. Effective source impedance seen by each power amp will be 4 times as high. Spec for the B5 is 150 ohms, so we'd be looking at 600 ohms - nothing to worry about.

 

[naca5]

Thanks
I need to drive 2 amps from one input (two times R&L)

And thanks again for your input, very helpful.

 

[AndrewT]

The B5 output also needs the current capability to drive two sets of cables. The capacitance in the cables can demand more current than a 10k Zin at the receiver.

 

[naca5]

Ok then the shorter the better ?

 

[AndrewT]

Yes short cables stand a better chance of having less effect on the electronic circuits.
The biggest effect is speaker cables, so I make these the shortest.
A Buffer that has adequate current capability can drive short or medium or long cables.
I use an added Buffer where any Source may be inadequate and that allows me to use any short, or medium cables.
I have experimented with 10m cables run from the balanced outputs of an emu1212m and could not detect any difference between the CDP direct and the computer stored CD files.

 

[naca5]

Well I'm running 4,5m of speaker cable, so that's a bad news ;-) (and running active meaning 3x4,5m per speaker!!!)

I must think about that...

 

[AndrewT]

running active means the speakers cables can be 300mm long, not 4500mm long.

 

[naca5]

I was not aware of this rule...ghost, I'm totally wrong....I must rethink the set-up.
Are you serious about 300mm?

 

[AndrewT]

Yes, mount the active amplifier right at the back of the speaker. Three channel amplifier driving the 3way active speaker.
It could be inside the speaker box, or under the speaker box, or hung on the back of the speaker box, or on it's own stand right behind the speaker box.

 

[naca5]

I will try to give a try,
but in that case, rca's will be at least 2000mm long....

 

[AndrewT]

That's OK.
The Buffer in the Source should be made capable of driving the interconnects.
As I said earlier the standard EMU 1212m was capable of driving 10m interconnects with no apparent loss of performance.
I use a DCB1 to drive 3m star quad interconnects. It's appears to be neutral (no sound effect). Star quad have roughly double the capacitance of twisted pair.