LDR attenuation module | V3 & V4


The quad LDR Module works only with the V3/V4 series of Tortuga Audio preamps and preamp attenuator/controller. Click here to check out the single LDR Module for the V2/V2.5 series preamps/controllers.  The quad LDR module was first released along with the ePot.V3 series Mini and Max preamp controller & stepped attenuator models. The newer V4 series controllers uses the same quad module. An LDR module is usually purchased at the same time as a Mini or a Max preamp controller board, however, the quad LDR attenuation module can be purchased here separately.

SKU: LDR_Module2 Category:
Print Friendly, PDF & Email

The V3 and V4 series Max and Mini preamp attenuator/controllers both require a quad plug-in LDR attenuation module. An LDR Module is usually purchased at the same time as a Max or Mini controller but can also be purchased separately here.

quad ldr module2 - top view
LDR module | top view

ePot.V3 Max DIY preamp attenuator & controller
ePot.V3 board with quad LDR module installed
quad ldr module2 - side view
LDR module | side view

Each quad LDR module has 4 embedded LDRs, an EEPROM memory chip, plus 2 sets of pin headers that plug into corresponding sockets on the Max and Mini controller boards. The memory chip contains the attenuation/calibration data tables for each LDR at one or more impedance settings.

Each LDR module handles both left and right stereo channels. Each channel uses 2 LDRs in a series/shunt configuration. Each LDR is individually controlled by the microcontroller located on the Max or Mini board. The microcontroller uses the calibration data stored in the EEPROM memory chip to generate the resistance values needed for each of the 100 volume steps.

When used in a Max board, an LDR attenuation module can be re-calibrated as needed and can be re-configured for any impedance setting from 1k to 99k with 20k being the typical fixed default impedance level for setting #1. This is only possible with the Max and not the Mini. The Mini does not have the built-in ability to calibrate its LDR module.  For this reason you must specify the fixed impedance of the LDR attenuation module when purchasing one for a Mini controller board.

More information on LDRs and their use in Tortuga Audio products can be found in our online product documentation here.

Scroll to Top