to George : jak to máte připojené ??
něco málo z toho odkazu:

From our findings when using the unit as it comes out of
the box, the noise experienced only happens with unbalanced connections and not
due to a failure with the DL1608. We (the manufacture of this product) strongly
recommend all DL1608’s to be operated with balanced cables and balanced devices
for Aux Sends and Main Outputs. Doing so will result in No Hum and No Whine at
all. Mackie always recommends using balanced cables and connectors whenever
possible. The DL1608 is a professional product and it is designed to be used
with professional balanced connections.