PASS THRU: Pushing this button twice, sets the pre-amplifier to it’s default low gain setting, selects volume step 64 (0 dB) and input 5. We have intentionally made this command a two step operation such that you will not accidentally select this command with it’s associated high volume. Pressing the button once will bring up the question of “YES” on the display. If you are sure that you wish to access the pass through function, press the button a second time. There is a time out built into this command sequence. If you do not confirm the “pass thru” command within 7 seconds then the command sequence aborts and the XP-10 resorts to it’s previous status. DISPLAY: The default setting for the display is “bright”, pressing the display button once changes the display to it’s “dim” or “low intensity” setting, pressing the button a second time selects “off ” for the display. When “off ” is selected any other control function will cause the display to indicate product operational status for approximately 7 seconds and then the display will once again blank. Pressing the display button a third time cycles back to a “bright display”
We recommend the use of the balanced output mode where possible. Balanced input to power-amplifiers will typically retain the character of the input mode, but offers less distortion, less noise, more gain, and more voltage swing, without compromising the sound.
With balanced operation, the common mode rejection of the preamp reflects the intrinsic common mode rejection of the topology, the matching of the gain devices, and the matching of the attenuator channels. In this case we have been able to keep the total mismatch to about .1%, for a common mode rejection of approximately -60 dB.
The input system of the preamplifier will exhibit full common mode noise rejection with passive balanced sources, where the negative input is connected to ground at the source through the appropriate source impedance. This allows adaptation of unbalanced sources to balanced operation with passive cable connections in a manner that achieves the noise rejection of active balanced sources.
The use of a micro-controller allows all of the preamplifier functions to be repeatable and accurately controlled. The micro processor only controls the functions of the preamplifier. At no time does any of the input or output signal come into contact with the digital control signals. The digital circuits are powered by a power supply that is isolated from the analog supply. Should it ever be necessary to update the software that controls the functioning of the preamp only the socketed micro processor need be changed.
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