The ClariT cannot have the negative outputs of the speaker terminals tied together. Most active sub high level inputs have the negative leads tied together going to ground. The ClariT doesn't have it's negative terminals tied together. This would basically send the amplifier into a protect mode and probably fry it in the end.
All,GHM is absolutely correct.
The Clari-T-Amp uses the Tripath TA2024 chip, which CANNOT
have the negative speaker output terminals tied together.
Most (if not all) active subs with speaker-level inputs have the Left and Right negative speaker-level inputs tied together (usually to GND). If you connect the Clari-T-Amp (or the SI, Teac, and other Tripath chips for that matter)
in such a configuration, you'll most likely get a distorted output and cause the chip to go into a protection mode!
This is why I am offering optonal volume controlled RCA outputs for the Clari-T-Amp. You'd simply run a pair of RCAs from the output jacks to the line-leve (RCA) inputs of the sub. When you raise and lower the volume of the Clari-T-Amp, the speakers and subwoofer volume will raise and lower together.
Most line-level (RCA) subwoofer inputs have a high input impedance, so loading shouldn't be a problem with most sources (CD players, dacs, etc).
NOTE: Using a Y-splitter out of your source will make your subwoofer play at one constant volume! You need it to be volume controlled.
You can always purchase the Clari-T-Amp without the built-in volume control (power amp only), and use your own preamp that has "preamp outputs" (RCA) which would also be volume controlled. I prefer passive over active (much less coloration) to keep things all-battery powered, but the choice is yours...