Does splitting a preamp line level preout halve the voltage?

[merc]

I will be splitting my subwoofer preout and then running the two channels to an outboard amp. The preamp preout voltage is rated at 1v, 9v max. Does a splitter effectively cut that output to .5v per split? If so, does that effectively limit my amp power to half its' rated max output?
Thanks for your help!




Take Care,
merc

[Lexman]

That is a great question merc! I don't have the answer, but I will try to find someone that can comment on this if no-one "bites" soon.

I don't think that it splits in half, but I don't know for sure. I am splitting my sub signal, and seem to have no loss that I could attribute to this.

Also, if 1 split produces no loss, how many splits before loss does show up?

Lex

[Andrew Pratt]

I don't think it affects the signal stength if its a simply Y splitter.

[migliore]

I'll take a 'stab'..

You are usually interested in the voltage from a noise point of view. In this case, the voltage remains the same b/c both devices are connected to the same branch. However, the same current is now driving both loads. Since this is line level, not speaker level, current is small. This should be fairly insignificant.

Did I botch that up?

At any rate, I split my sub out to the sub and TT's. Sounds (and feels) good to me.

Rob




Reviews and System

[MRWILLL]

Before I bought my Lexicon, I talked with Greg (Lex customer servive) about the same situation. He told me that Lex's line of pre/pro's were made for this type of serious hook up on eack output without any signal loss what-so-ever. I have a Monster "F" series connector on my Center,Front,Rear, and sub channels.




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[Robbie]

merc,

It all depends on the input impedence of the devices connected. If the input impedence of the devices connected are the same like two channels of the same amp than yes it will effectively half the signal to each input. Therefore you may have to bump up the gain on your sub 3db to compensate. If your going to drive 2 subs than they would combine and no extra gain would be required unless you just like it that way. I don't think eather way it would make much of a difference.

Robbie

[Lexman]

Great responses guys, thanks.

Lex

[Robbie]

merc,

Man I'm sorry... I really need to quit smoking that stuff. Anyway, The voltage across a parallel circuit stays the same in other words you will get the same voltage across both however the current will be split depending on the impedence of the circuit. Still don't think it will make any difference.

Sorry for my misinformation.

Robbie

[merc]

Thank you all for your help!
As it turns out, the split subwoofer output is plenty strong to drive the amps to their max with my subwoofers...




Take Care,
merc

[Allan J.]

Some preamps have self loading low impedance outputs (600 to 1000 ohms) intended to drive high impedance inputs (10K to 40K ohms or so) of power amps. What this means is that the power amp input is supposed to sense the voltage but is not expected to draw current. In this situation splitting one output to feed two or more inputs won't make any difference, two inputs won't halve the voltage.

Low impedance outputs that require a matching impedance input are those where the next device's input must draw current to make the circuit work correctly. Here the total impedance of the inputs affects the voltage delivered.

If the preamp output is high impedance, connecting it to a device with a matching input impedance is important. Whatever you connect it to will also affect the voltage delivered and therefore you will have to compensate by adjusting the gain (level or volume control) on your preamp. A higher impedance output tends not to work well with a lower impedance input for the next device.

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