Block out the noise. Stop the feedback.
The subwoofer conundrum
Sub-woofers need a lot of power and they are not too sensitive to high frequency noise. Speaker manufacturers like to match their subwoofers up with some pretty low quality amplifiers, with switching power supplies and not much filtering. The sub-woofers sound good, but the problem we found is that this noisy subwoofer is connected to your ultra clean, ultra precision analog output. This creates obvious noise and distortion on your main amplifier and speakers. Its like serving fine wine in dirty glasses. It all started when we had a customer who preferred their preamp. In our experience, there is no preamp that sounds better than having no preamp. Noticing a powered subwoofer, we turned off the subwoofers and the sound came alive. Turned them on but disconnected the input. Still sounded great. It was not the sound of the sub that was the problem, it was the pollution caused by it.
A necessary solution
The solution was an isolation module that provides a subwoofer output that is completely ground isolated from the source and blocks noise and feedback. One of the roles of a preamp is to provide dual isolated outputs, but as an all purpose tool, it filters and isolates all the outputs. It blocks much of this sub feedback, but at the expense of the quality of the mains. This isolator allows a minimalistic signal path. This gives your primary amplifier a perfect signal and your subwoofer an isolated input.
Balanced Sub Isolator (XLR)
This unit is made for any DAC or Preamp that has a single balanced output for their main amplifiers and needs a subwoofer output. This module provides a perfectly unmodified pass through, and a fully isolated balanced output for the sub. This is much better than a Y cable.
Single Ended Sub Isolator (RCA)
This unit is made for any DAC or Preamp that has one single ended output for their main amplifiers and needs a subwoofer output. This module provides a perfectly unmodified pass through, and a fully isolated single ended output for the sub. This is much better than a Y cable.