[Corbin Johnson]

I recently purchased a used SP1.7 primarily seeking a high quality two channel preamp with the added benefit of a good surround sound processsor all within one unit.  Prior to this purchase I used a Marantz receiver for surround sound and a MiniMax tube preamp for 2 channel.  The MiniMax had dual RCA outputs.  I connected one pair of the RCA outputs to my Nuforce 9SE amps for the front speakers and connected the second pair to my powered subwoofer.   

The SP1.7 only has one pair of RCA outputs for the main speakers and another pair of XLR outputs for the mains which the manual says can be used at the same time.  I'm running XLR outputs to my Nuforce amps and the RCA outputs to a powered subwoofer.  The signal strength from the XLR's is almost double the RCA, so I have to turn the power up to almost full volume on the sub amp. 

Can I run a splitter from the single RCA outputs to power both the Nuforce amps and subwoofer amp?  I've tried this and it seems to work fine, but sometimes I think I'm hearing some distortion.  I've had problems using a splitter for the mains and sub in the past, so I'm wondering if there is a problem with this configuration.  I notice the BP26 comes with dual RCA outputs and have wondered if this is the same as simply applying a splitter to the single output of the SP1.7 or if there is some electrical component that segregates the two outputs.

Thanks,

Corbin 

[James Tanner]

Hi Corbin,

Yes you can use a splitter but is there an issue with having to turn the sub up to full volume?

james

[brucek]

Can I run a splitter from the single RCA outputs to power both the Nuforce amps and subwoofer amp?

You may 'Y' split this signal many times without concern.

This line level connection to the power amps is a low level, high impedance connection where almost no current is drawn. We're not concerned with power transfer here - the preamp acts as a voltage source.

Since the split signals are in parallel, they remain the same voltage and since the current is quite low as a result of the rather large impedance mismatch between the preamp output (typically 100 ohms) and the power amps input (typically 10K to 50K), you may split the signal without any fear of distortion or volume change.

brucek

[Corbin Johnson]

James & Bruce,

Thanks for the replies.  I wanted to make sure there was not an issue using the Y splitter on the RCA outputs. 

Jim, there really isn't a problem using the XLR outputs and turning the sub volume way up.  This is plenty loud for the sub, except sometimes I might like to have more head room to crank it higher than max volume compared to speaker volume via XLR connectors, like when I have some bass headed friends over.  I just need to make sure I adjust the sub volume way down in speaker set up for listening through the processor so I don't blow the subwoofer.  I'll play with both approaches to find a preference.