Feature: ►Performance of Preamp has entered a new era: Pre90 Preamplifier & Ext90 input extender. Fully balanced amplifier structure for both balanced and single-ended signals. Pre90 could set volume memory for each input or volume memory for each output. ► Ext90 could extend you more inputs: A standard Pre90 provide you 1 x RCA and 1 x XLR stereo inputs. But when it working with a Ext90, they could provide totally 2 x RCA and 4 x XLR stereo inputs. This is enough for multi source systems. ►Selectable XLR / RCA output: The output of Pre90 could be config to “XLR only”, "RCA only" or "XLR + RCA ". Therefore, the amplified signal can be connected to two different amplifiers. ►Ultra-high Performance NFCA modules: It provides excellent DC and AC performance. Ultra-low noise of 0.3uv is milesahead of the competition, giving an absurdly high dynamic range of 145db and no audible noise and darkest background. ►Relay volume control: If the volume was set high while turn on or switch in, Pre90 will automatically reduced to a safe volume to avoid your speakers/headphones blown by sudden high volume.