CONNECTING A SUB WHEN THERE IS NO SUB-OUT CONNECTION

Get that second sub before you do damage to your amps. Then connect each sub’s high level input to its respective amplifier. I had this dilemma with my REL Classic 98 and pair of Quad 303 mono amps.  Fortunately my preamp has both balanced and unbalanced outputs, so I run the amps off the XLRs and use the RCAs to feed the sub with a Y connector. 

When I first bought a subwoofer, I ran it off the variable preamp outs.  Now my subwoofer is behind my listening position and I am using the SVS product that @mattw73 mentioned and it works great. 

@buellrider97 wrote “I’m ASSUMING that you are just experimenting with a sub on hand to see what it sounds like.”

RESPONSE:  I selected the Martin-Logan sub because my main speakers are ML Electrostats.  I wanT to ensure that I used subs that would match the panels’ speed. My brother has MLs, Maggies and uses an ML sub with success.  I try not to experiment and buy the right product once (well, except for my streamer which will be replaced—I’ve already hinted to my wife what I want for my 60th birthday).  When I purchased my CLSs decades ago, there was no sub that could keep up with the panels, but I was seduced by the CLS’s magical mid-range and have rarely been tempted to move away from them. 

@kirkwallace wrote “ REL recommends one subwoofer per monoblock.  So the advice above and what I’ve written below still is correct, but you would chose just right or left channel to connect to a single subwoofer or transmitter. “

RESPONSE:  I’ll attempt this approach later today. 

@mattw73 wrote “ SVS makes a line level device that wires/connects to the left & right outputs on the power amp. And then allows you to run RCA cables from this device to your sub. No balanced outputs though.

RESPONSE:  I’ll look into this.  

@dynacohum wrote “Get that second sub before you do damage to your amps.”

RESPONSE:  I’ll probably pull the trigger this weekend on a second sub.  I hope adding this subs will give be the  low end that I’m looking for so that I can stop looking for new $peaker$.

I run a line out of my Herron 360 REF to the x’over of a Martin Logan sub...have two, then out to my mono amps

There are other & cheaper line level devices out there than the SVS Unit. I just assumed that since SVS had been mainly focused on subs that they designed it correctly. I only use it depending on the preamp I'm using but I feel like it works well. 

When using a proper solid state amp I feel like I lose nothing..maybe having to add a tick more gain to the sub sometimes. The device does reduce the voltage around negative 30dBV. Adding no noise, distortion, or compromising the amp in any way.  With certain tube amps I've perceived some differences in the subs performance. 

It can handle high voltages like 500 watts RMS & double that for peaks. It has binding posts for inputs..I use spades at the amp and banana plugs to the SVS device. It basically just safely converts high voltage amp output to low level rca outputs. It's a passive device which I like.. nothing extra to plug in or ground. No matter which amp I've used I've never heard any dc thump or other noises when turning the amp off while the sub is on. Which is how it should be. 

It's a cool little device to always have at your disposal. Though if you buy or have quality sub/subs with high level inputs already available there is no need for this device. I primarily have been using SVS subs the last 5 years or so. I don't have speakers that demand ultimate speed or sensitivity from a sub. And the SVS DSP phone app was a game changer for me at the time. The room compensation feature & just the 3 PEQ tabs of the original Pro models made integration so much easier & better. Their newer models offer 5 PEQ tabs now I believe. My older Pro models might not be the best in overall performance but for me the PEQ/DSP options make up for it. Though I do see more sub manufacturers adding some type of legit DSP to their subs.