LDR Attenuation Module


The ePot Mini and Max preamp controller & stepped attenuator models both use the same plug-in LDR attenuation modules. A LDR attenuation module is required, and usually purchased at the same time when purchasing either a Mini or a Max preamp controller. However, LDR attenuation modules can be purchased separately.

SKU: ePot LDR Module Category:
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LDR attenuation module

The ePot Max and Mini both require the use of the same plug-in LDR attenuation module which is usually purchased at the same time.

The LDR attenuation module is shown below removed from, and located next to, an ePot.V3 Mini. Below that image is an ePot.V3 Max with the same LDR attenuation module installed.


ePot.V3 Mini top view with LDR module removed
ePot.V3 Max top view - horizontal

Each LDR module has 4 embedded LDRs plus an EEPROM memory chip. The memory chip contains the attenuation/calibration data tables for each LDR at one or more impedance settings. The LDR module provides 100 steps of attenuation between -60 to 0 dB.  Each channel uses 2 LDRs in a series/shunt configuration. Each LDR is individually controlled by a microcontroller, located on the Max or Mini, which uses stored calibration data to achieve the resistance values needed for each of the 100 volume steps. Tortuga Audio does not pre-match LDRs because the calibration process normalizes the behavior of each LDR around 100 targeted sets of resistance values.

When used in an ePot.V3 Max, 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.

Only the ePot.V3 Max is capable of calibrating an LDR attenuation module. The Mini does not have built-in LDR calibration.  Therefor, you must specify the fixed impedance of the LDR attenuation module when purchasing one for an ePot.V3 Mini.

Hardware, operation and control manuals

A more comprehensive description of the epot.V3 Mini and Max hardware, installation, operation, and controls can be found in the following online documentation:

ePot.V3 Max hardware manual 

ePot.V3 Mini hardware manual 

ePot.V3 Mini & Max operation and controls manual


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