TOPPING Pre90 Preamplifier & Ext90 Input Extender Hi-Res Audio NFCA Modules 2*RCA 4*XLR Combination

TOPPING Pre90 Preamplifier & EXT90 Input Extender Preamp Amplifier Pre-amp Ultra-High NFCA Modules RCA Balanced XLR Output for D90 A90 Audio DAC with Remote Control.
Safe Volume, so you don't get shocked: The safe volume feature on Pre90 will kick in when the saved volume of target input or output exceeds the set safe volume, and reduce the output to safe volume, protecting your expensive equipment and your priceless hearing. The safe volume function can be turned off in the settings.
Ultra-high Performance NFCA modules: Pre90 uses the similar NFCA ( Nested Feedback Composite Amplifier )module from flagship A90 Voltage Current hybrid feedback architecture long with UHGF ( Ultra High Gain Feedback ) technology provides excellent DC and AC performance. Ultra-low noise of 0.3uv is miles ahead of the competition, giving an absurdly high dynamic range of 145db and no audible noise and darkest background.
Relay volume control: A large number of high-quality Japanese small-signal relayed volume control of Pre90. Brings the advantages of precise control remote control, longevity, and complete channel balance the volume was set high while turn on or switch in, Pre90 will automatically reduce to a safe volume to avoid your speakers/headphones blown by sudden high volume.
A wire with amplification: An excellent preamp should have top performance, just like a wire that can amplify signals. As you can see, Pre90 did it.
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 an Ext90, they could provide a total of 2 x RCA and 4 x XLR stereo inputs. This is enough for multi-source systems.
Note: The actual noise level is obtained by boosting the noise of Pre90 by 40db using a low noise amplifier in front of the APX555B then dividing the measured noise by 100 times.