My product development iteration involves improving my output chain as I reveal more transparency at the DAC and upstream. So when a change is made I need to be able to hear the tangible benefits on sound quality. Currently, this is what I have:
Analog output from Mojo2 (3.5mm to Stereo RCA) goes into an RF•STOP SE Signal Filter (EXTREME variant) to a Benchmark HPA4 amp and then to HE1000se headphones. As I presented in my blog posts here and here, RF•STOP Signal Filter is a blocking filter that prevents downstream RF noise from entering Mojo2. The skin effect filtering technology does not affect Mojo2's baseband analog audio output - only high frequency 'out-of-band' noise is attenuated. ...and this greatly benefits Mojo2's small signal processing. Consider the sources of downstream RF noise:
- Noise from the switch mode power supply in the HPA4
- Noise from AC mains power and other audio components
- Headphone cable, acting as an antenna for environmental EMF
- RCA interconnects acting as an antenna for environmental EMF
Without RF•STOP SE Signal Filter, a veil drops over the sound - so one is required. For my REFERENCE•M2 system, I have determined that two Signal Filters (in series) are required to remove all vestiges of downstream RF noise. Per the drawing below, two RF•STOP SE Signal Filters can be placed one after the other or stacked, using commodity adapters or jumpers.
