I have an S20/S30/S60 combination and am plagued with noise being introduced down the BNC SPIDF connection between the S20 and Aqua La Scala DAC. The noise is a “zit zit zit zit’ sound rather than a constant hum one might expect from an earth loop.
When not listening, the La Scala and preamp (Audio Research LS28) are turned off and the amps (4 x bridged Nuprime STAs) and S20/S30/S60 are left turned on. Even like this the noise makes it way through to the right channel. It’s there when listening to the turntable as well.
Powering down the S30 makes no difference, I either have to disconnect the SPDIF connection or power down the S20, then the system is perfectly quiet.
Have played around with power feeds. The S60, La Scala and LS28 are feed from an IsoTek Aquarius and the Nuprimes from the wall. Feeding everything from the Aquarius made no difference.
Is anyone able to shed light on what is happening and suggest a fix? Look forward to your feedback.