About
What we make
Tortuga Audio designs and builds LDR-based preamp controllers and attenuators for DIY audiophiles and audio electronics enthusiasts. Our current product is the ePot.V4 Preamp Controller system — a digitally controlled, remotely operated volume control and input switcher that uses light dependent resistors instead of mechanical potentiometers or stepped attenuators.
The technology
We control volume with light. Specifically, we use LDRs (light dependent resistors) driven by LEDs to create a continuously variable attenuator with no mechanical contacts, no wipers, no switches. The result is a volume control that’s essentially a variable resistor controlled by software.
The V4 system’s key technical differentiator is its in-situ calibration algorithm. Most LDR-based designs require pre-matched LDR sets (expensive, time-consuming, limits serviceability). The V4 normalizes the behavior of four LDRs in under 15 minutes via a user-initiated calibration cycle — no matching required. You install four LDRs from the same batch, run calibration once, and the system compensates for individual LDR variances in firmware.
The V4 system includes the controller board, LDRV4 attenuator module (current 4-LDR design), OLED display, remote control, optional buffer board for active preamp applications, and a 5V linear power supply. We also sell the legacy LDRV2 module to existing V2/V25 board owners for upgrades.
Who we are
Tortuga Audio is a small operation based in central Oregon. We sell direct via tortugaaudio.com and through word-of-mouth in the DIY audio community, primarily on AudioCircle. Components are sourced domestically and internationally; all assembly is done in the US.
The company was founded in 2010 in south Florida and relocated to Oregon in 2023. That move effectively stood the business down for about two years while a new shop was being built. We’re currently at a strategic inflection point — evaluating what products to offer going forward and whether a limited run of finished preamps makes sense alongside the DIY controller systems.
We are an intentionally low volume operation. This is a niche within a niche, serving people who want something specific that is rarely available off-the-shelf.
Morten Sissener | founder & designer
I started Tortuga Audio because I wanted LDR-based volume control for my own system and nothing on the market did what I needed at a price that made sense. So I designed it, built it, and realized other people wanted the same thing.
I’m an engineer by training and career — technology development, business development, & solving problems that require both hardware and software. Audio electronics is where that intersects with my long-standing obsession with music and gear. I believe well-recorded music deserves capable playback equipment, and that “capable” doesn’t require mortgage-level spending or magical thinking about wire directionality.
The shop is currently under construction (expected completion mid-2026). Once that’s done, I’ll have the space to evaluate whether small-batch finished preamps are viable alongside the controller systems.
If you have questions about the V4 system, LDR technology, or whether this approach fits your application, email me directly. I usually respond to everyone.
