# Sub cabling



## Downhome Upstate (Oct 19, 2014)

I have a (stereo) pair of Rythmik F12G's w/the A370PEQ amps. My line stage has dual pre outs and no processing/xover. The A370PEQ's have RCA line ins and high pass filter RCA outs back to the amp (either high-power SS, very low power DHT SET or EL-34 pentode ultralinear, depending on the flavor of the week). 

Because I'm placing the preamp and amp on the side wall, line-level sub cables would be 15-20' long each. I'd probably get a pair of the ultra low capacitance interconnects for this application from Blue Jeans Cable.

Any experience with this configuration, vis-a-vis plain old speaker-level inputs to the subs? Any thoughts on impedance issues or impedance matching?

Thx,

Mike


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

Hey Mike,

Fifteen to twenty feet isn’t really that long. Just use a top-quality cable and you’ll be fine. No reason to get low capacitance cablea either, that’s only relevant to help prevent high frequency loss for really long cable runs. Not an issue unless your sub gets all the way up to 20 kHz. Not sure what you mean by impedance matching issues – do you mean line-level? If so it’s not a problem.

Regards, 
Wayne


----------



## Downhome Upstate (Oct 19, 2014)

Wayne A. Pflughaupt said:


> Hey Mike,
> 
> Fifteen to twenty feet isn’t really that long. Just use a top-quality cable and you’ll be fine. No reason to get low capacitance cablea either, that’s only relevant to help prevent high frequency loss for really long cable runs. Not an issue unless your sub gets all the way up to 20 kHz. Not sure what you mean by impedance matching issues – do you mean line-level? If so it’s not a problem.
> 
> ...


Thanks, Wayne. (I have since learned to read. The quick guide that Brian includes with his subs is very helpful.) What I was concerned about, impedance-wise, was this:

If I used the subs' line inputs and high-pass line outputs for bass management, I would have 30-40' of coax with the associated capacitance for each sub between line stage, sub and back to the power amp, plus the reactive impedance presented by the sub's plate amp. In addition, I use different amps (solid state and tube) depending on the speakers in use. I believe the front ends of the amps have very different input impedance characteristics. I was worried that connecting the F12G's like this would create a passive tone control circuit.

By reading the quick guide and staring at the plate amps, I realized that I can just use the line inputs and control the crossover manually on the A370PEQ amp. No need to use the HPF line-level outputs. 

Thanks again.

Mike


----------

