Connecting Sub to my preamp

I tried the Klipsch KSW10 and it did not work at all for me.

I used the Pre Amp out as my only option on my amplifier. Maybe you’d need to use the Passive Out on your preamp?

Since these subs have their own amp, I would not use the speaker terminals.

If you have no crossover control on the amp and then on the sub (aside from the Klipsch), it could be a mess. I tried 4 different subs and I am still not happy. Unless you go with a high end sub for your higher end speakers, like the KEF, it will be boomy, noisy and crush the speakers’ bass. I am very ignorant in all things hifi and hopefully it will work out for you against what I experienced. The good thing about using one with an app such as ELAC or SVS is that you can adjust it in 3 seconds from your chair and get a decent compromise for any given music

You will need a pair of Y-Adapters plugged into the preamp out. Two pairs of RCA cables will be needed. One pair from left preamp out to left amp in and subwoofer in, same thing for the right channel. Something like this will be needed!!

My preferred method for subwoofer hookup (and best integration) is to run the sub parallel to the main speakers off the speaker outputs of the amp, or from the speaker inputs themselves to the high level inputs of the sub, as opposed to from a preamp output to the low level inputs.  Allow the main speakers to run full range (avoiding running the subs high pass filters through your main speakers), and only use the sub to augment what the mains do. 

The theme here is to feature the speakers, not the sub.  Set the low pass frequency of the sub at a very low setting (40-50hz if possible), then set the gain very low so that you only hear the sub in very bass heavy passages.  You'll need to experiment with sub placement and the phase setting.  If done well, you'll barely hear the sub, except on passages where there's a lot of bass content, and even then it should be more felt at the lowest frequencies than heard.  YMMV, but this is what's worked best for me.  

If you can’t run them off the speaker outputs, the preamp variable outputs is the next best.

@knotscott  I definitely want to follow what you are saying. What is your sub? What are low and high level inputs on the sub? On my current sub I don't even have speaker inputs. 

I definitely want to follow what you are saying. What is your sub? What are low and high level inputs on the sub? On my current sub I don’t even have speaker inputs.

That definitely narrows your setup options then.  Just use the inputs you have and experiment with placement, and gain settings til you like it. 

I can’t post pics on this forum, but you can certainly google to see the numerous types of input (and output) options on the plate amp on the back of many active subs.

My sub(s) are Definitive Technology PF-1500 and Dayton SUB-1200. Without getting too wordy with details, both are active subs with plate amps built into the backs. Both offer a couple of input options (many do). 1. RCA phono jacks that are low level inputs from a line source like a preamp output. 2. They also have high level speaker inputs that accept the speaker output from an amplifier....they basically reduce that amplified signal down to a lower voltage that’s similar to a line level voltage so that the sub’s amp can then re-amplify the signal and drive the sub, so the main amp only has the responsibility of driving the main speakers. Many subs also have a variable low pass (and high pass) crossover filters, gain knobs, 0 and 180 phase options, etc.

@knotscott thank you, that's perfect, I am learning a lot

Thank you all. I will be trying the RCA from Pre Out to Sub and see how it goes!

I use the same method as @knotscott with my McCormack dna1 deluxe. My subwoofer has “speaker” and rca connections.I tried it running out of my preamp into the rca and it introduced a lot of noise and surely didn’t sound the same as going from the dna1 to my sub with speaker wire.

when going the rca route make sure your cables are suitable. Filtering out noise was one my cables problems.

db