Flexible preamp platform
The LDR3000x.V3 is designed around our high performance V3 Max electronic LDR stepped attenuator & preamp controller in combination with an attractive enclosure composed of anodized and powder coated aluminum and sustainable bamboo.

The LDR3000x preamp platform can be configured as either a passive or active preamp. The active version can be configured as either a solid state or tube based preamp. Regardless of preamp type, you can opt for single-ended RCA signals only, balanced XLR signals only, or a combination of both. Combined signal types requires a wider version of the enclosure but has the same height/depth as the narrower build and is otherwise identical.
All outputs are dual/parallel for convenience when bi-amping or driving both a main amp and a separate subwoofer amp.
Nine (9) preamp configurations
The flexible LDR3000x.V3 preamp platform is available in nine (9) different preamp configurations. Each configuration is listed below along with its base pricing.
All configurations start with the V3 Max attenuator/controller in the LDR3000x enclosure. Different internal modules and rear panel assemblies are used in each configuration. Since these configurations are mostly modular, it’s not too difficult to change to a different configuration later on.
Configuration # | Preamp Type | Signal Type | Base Price |
---|---|---|---|
1 | Passive | Single-ended | 3 RCA inputs & 2 outputs | $1495 |
2 | Passive | Balanced | 3 XLR inputs & 2 outputs | $1795 |
3 | Passive | Mixed RCA & XLR 3 RCA inputs & 2 outputs 3 XLR inputs & 2 output | $2295 |
4 | Active | Solid State | Single-ended | 3 RCA inputs & 2 outputs | $1795 |
5 | Active | Solid State | Balanced | 3 XLR inputs & 2 outputs | $2295 |
6 | Active | Solid State | Mixed RCA & XLR 3 RCA inputs & 2 outputs 3 XLR inputs & 2 output | $2795 |
7 | Active | Tube | Single-ended | 3 RCA inputs & 2 outputs | $2295 |
8 | Active | Tube | Balanced | 3 XLR inputs & 2 outputs | $2795 |
9 | Active | Tube | Mixed RCA & XLR 3 RCA inputs & 2 outputs 3 XLR inputs & 2 output | $3295 |
A great sounding preamp
Built around our latest ePot.V3 Max stepped attenuator & preamp controller, the LDR3000x is arguably our best sounding preamp to date whose subjective performance will please even the most discriminating listener.
V3 Max electronic stepped attenuator & controller
The heart of the LDR3000x is our latest preamp attenuator/controller, the ePot.V3 Max (the “V3” or “Max” ). The V3 is the culmination of over a year of development and refinement of our evolving 10+ year LDR attenuation technology. The V3 combines exceptional sonic performance in an integrated, software driven, preamp controller that includes input switching, remote control and a menu driven interactive high contrast OLED display interface.
Features of the ePot.V3 Max include:
- 100 step attenuator over 60 dB range
- Smooth volume stepping with no sonic artifacts
- No mechanical switches in the signal path
- Menu driven visual control with high contrast 256 x 64 OLED display
- LDR (light dependent resistor) attenuation
- precision closed loop LDR current control
- integrated offline self calibration of the LDRs
- replaceable plug-in LDR module
- Integrated input switching (3 single-ended stereo sources) via LDR switches
- Remote controlled (Apple infrared remote)
- Manual control via rotary encoder with integral push button
- Smooth muting/unmuting
- Left/right channel balance (+/- 10 db)
- Updateable firmware
Operating instructions
The operation of the LDR3000x.V3 is indistinguishable from the underlying ePot.V3 Max Controller/Stepped Attenuator at the heart of the LDR3000x. The operating instructions for the V3 Max are available in our online product documentation and can be found here.
Common specifications
The following specifications are common to all LDR3000x.V3 configurations. You can find specifications for the active solid state and active tube versions in their own tabbed sections.
Criteria | Description |
---|---|
Preamp Overview | A remote controlled, 2 channel stereo linestage preamp that can be configured as a passive or active preamp with up to 3 single-ended inputs and/or 3 balanced inputs. The active version can be solid state or tube based. |
Attenuation | An analog, 2 channel stereo, electronic stepped attenuator with 100 smooth steps over -60 to 0 dB range with using two light dependent resistors (LDRs) per channel in a series/shunt L-Pad voltage divider configuration. |
Attenuation Module | Single plug-in replaceable LDR attenuation module with 4 embedded LDRs plus EEPROM memory chip for storing attenuation tables derived from in-situ calibration of the LDRs |
Controller | The controller uses an embedded 32 bit ARM M3 Cortex 100 MHz microcontroller to drive a 16 bit command DAC tied to 4 precision LDR current control loops each of which controls the resistance level of 1 LDR. The controller also handles the remote control decoding, manual encoder inputs, input switching, menu driven graphical OLED display and LDR calibration process. |
LDR Calibration | Embedded closed-loop offline calibration circuit which normalizes the behavior of each of the 4 attenuation LDRs over 100 steps of attenuation each corresponding to a specific targeted resistance value that varies with the input impedance setting which can be altered by the user if desired. Calibration can be run to compensate for performance drift, aging, or in the event of LDR Module replacement. Calibration is user initiated. Pre-matched LDRs are not required. |
Direct input | no coupling cap | The incoming audio signal is direct coupled with no AC coupling capacitors in the signal path. |
Input Impedance | Default input impedance is 20k ohms with ability of user to configure other impedance settings each between 1k and 99k that user can switch between to determine potential optimal input impedance for user's system. |
Channel Balance Adjustment | +/- 20 step channel balance adjustment at ~0.6 dB per step for a nominal max channel balance range of +/- 12 dB |
Remote Control | Interaction with the Display/Control Menu is done with a simple 7-button Apple infrared remote (or equivalent remote using 38 kHz NEC protocol and conforming with the Apple command/ID structure) |
Encoder Control | A subset of the controls are available through a front panel control knob attached to a rotary stepped encoder with integral push button switch |
Display/Control Menu | High contrast 3.12 inch white-on-black 256x64 pixel graphical OLED display mounted behind a tinted acrylic lens. Display is essentially invisible when preamp is turned off. The display provides an intuitive interactive menu driven control. Control Menu details are available online as art of the product documentation for the ePot.V3 Max controller at the following link: http://51.81.208.15/docs/epot-v3-operation-controls/ |
12V Trigger Out | A 12 VDC trigger out is provided via a mono phone jack. The On/Off state of the trigger out corresponds to the On/Off state of the preamp. The trigger out On state has a using adjustable 10 seconds delay with the default delay being 0 seconds (no delay) . |
Power Entry | 100-240 VAC mains via IEC power entry module with integral fuse drawer and mains power switch. IEC style 3 prong plug-in power cable. |
Internal Power Regulation | * V3 Max Controller Power Supply - 10 W, 100-240 VAC to 12 VDC converter followed by linear filter * V3 Max DC-DC power board - Dedicated 2 stage switch mode plus linear DC-DC regulation producing primary 3.3V plus +4.8V and -4.8V split voltage |
Enclosure | * Black brushed anodized aluminum front panel with dark acrylic lens inlay and large anodized aluminum volume/control knob in a machined recess * Black brushed anodized aluminum read panel with laser etched annotation * Top panel - black power coated aluminum * Bottom panel - aluminum with natural finish * Side panels - solid bamboo with durable satin polyurethane finish * Feet - platinum silicone hemispherical vibration dampening feet |
Circuit Boards/Solder | High quality lead-free printed circuit boards with 3% or higher silver content in the soldered parts |
ROHS | Compliant or exempted |
Fuses | One external fuse located in the IEC fuse drawer |
Ambient Requirements | Preamp must be operated in a stable, dry indoor environment only with stable ambient temperature within 60-90 degree F |
Dimensions | Narrow - 10 inches wide | 10.5 inches deep | 3 inches tall (including feet) Wide - 13 inches wide | 10.5 inches deep | 3 inches tall (include feet) |
Weight | ** TBD ** |
Other Specifications | Specifications that are specific to either the solid state or tube configurations of the LDR3000x.V3 are provided separately under those information sections |