Aurora Audio GT500 500 Series Preamp  From Aurora Audio

The Aurora Audio GT500 Preamp can accommodate any signal you care to throw at it, including high-level line inputs. The sensitivity switch provides 100 dB of gain adjustment from +80 dB to –20 dB and the level pot allows for fine adjustments. The level pot has an audio taper and is –20 dB at half rotation.

If you have to turn the pot below half way, the sensitivity switch must be adjusted at least two clicks more to restore the signal level at the expense of input headroom! Operating the unit with the output level at maximum ensures that you keep the headroom in the designed 26 dB region.

The DI input overrides the normal input and has 10 Megohm input impedance and around 10 dB gain. It can be used (to great effect) with musical instrument pickups, but works equally well with high-level signals.

The High Pass Filter is selected by moving its toggle switch to the right and a blue LED will glow to indicate section. Four frequencies are provided: 47 Hz, 82 Hz, 150 Hz and 270 Hz for the selections.