小弟昨天去官網問了一下有無 bypass 的功能, 以下是 BMC 的回答: The PureDAC has a preamp function, but it doesn't need a preamp. Sometimes new approaches are a little hard to understand. Normally you would expect that a direct connection to the DAC should be better than a connection via a preamp. In case of the PureDAC you are always directly connected to the DAC although you can enjoy having a volume control. Without the need of a digital volume control within the significant volume range the PreDAC can set the I/V conversion rate so it matches to your selected volume. If you just want a DAC with a standard output level, you simply set the line volume to "58" and disable the B.M.C. link. You might try different standard volume settings since the optimum level depends on your amplifier.