Dear Tour Participants,
I thought I'd elaborate on the possible ways you can evaluate the LDR300x.V3 that can make for a more interesting experience.
Active vs. Passive - The tour unit comes configured as an active preamp. However, you can remove the top half of the enclosure in order to access jumpers JPL and JPR located on the Interface Board near the right side of the rear panel. By moving the jumpers on on JPL and JPR from the "A" position to the "P" position you effectively bypass the active gain/buffer board and can operate the preamp as a passive unit.
Active - Unity Gain or +6 dB - The active tour unit is set to unity (1.0X) gain hence there's no actual amplification of the audio signal within the preamp. The 2 unity gain modules can be swapped out for a pair of +6 dB gain modules provided with the tour unit. Please be aware that the gain modules must be aligned properly such that the white dot on the plug-in module is on the same side of the 4 pin module header as the white dot on the board. Sound complicated but it will make more sense when you see it.
LDR vs Discrete Attenuation - The tour unit comes set up with an LDR attenuation module installed. This module can be removed and replaced with a discrete attenuation module that uses thin film resistors only. The LDR module has 100 steps of attenuation while the Discrete module has 127 steps of attenuation. Arguably a bit overkill at 127 steps but it was either that or 63 steps which, while plenty granular, would be considerably less than the 100 steps with the LDR. When swapping theses modules, please only do so by first powering down the preamp and either disconnecting it from your amp or making sure your amp is turned off. Common sense stuff.
When done with the tour unit and before packing it up and shipping it onwards, please put it back to its original default state of active, unity gain modules and LDR attenuation module.
Thanks and I hope you enjoy the tour.
P.S. To remove the top half of the preamp case, remove only the top 2 corner socket screws on both the front and the rear panels. Leave the bottom screws installed. Then gently rock/pry the top half shell up and off the unit.