Double Triode Limiter
Preamplifier
The IGS Double Triode Limiter (DTL) is a tube microphone preamp and opto-limiter that brings classic analogue tone into modern workflows. Its dual-stage triode design provides generous gain for everything from quiet ribbon mics to punchy drum transients, while the Hi-Z inputs make it a powerful front end for guitars, bass, synths and drum machines. With rich tube saturation, transformer-balanced I/O, and precise control over both gain stages, the DTL adds warmth, depth and musical harmonics to any source. Engaging the built-in opto-limiter enhances dynamic control, capturing peaks smoothly and protecting converters while doubling as a characterful compressor for drums, vocals or mix bus work.
The Heart of the Tone: A True Tube Front End
The Double Triode Limiter begins as a powerful dual-stage tube microphone preamp designed to work effortlessly with any microphone type. Its wide gain range handles delicate ribbons, dynamic mics and high-output condensers with ease. Electric guitars, bass, synthesizers and drum machines also shine through the dedicated Hi-Z inputs, which feed the grid of the first triode for authentic tube coloration. Whether tracking live instruments, reamping from a DAW, or warming up sterile digital sources, the DTL imparts rich saturation and musical depth.
Classic Opto Limiting, Reinvented
Beyond preamplification, the DTL integrates a musical opto-limiter inspired by revered 60s and 70s designs. An IGS-custom photocell governs the gain reduction, delivering smooth control over peaks without choking the signal. The limiter LED provides instant visual feedback, making it easy to tame transients, prevent converter clipping or apply gentle glue to a mix, bus or drum group. Its versatility extends well beyond tracking — the DTL can easily serve as a vibey, tone-forward compressor during production or mixdown.
Fully Featured, Professionally Built
Inside, the signal path is fully transformer balanced using Carnhill inputs and Edcor outputs, with nearly 300V DC on the anodes for authentic tube drive. Independent Drive controls for each gain stage let you fine-tune the exact amount of coloration, from subtle warmth to full-bodied saturation. Front-panel Hi-Z inputs, +48V, Phase, Pad and Gain switches provide all the control required for professional workflows, while the output meters ensure reliable gain staging. With musicality, flexibility and unmistakable vintage soul, the DTL stands as one of the most expressive opto-tube front ends available today.
Specifications
| Device Type | Optical Compressor |
| Optical Cell | Yes |
| Audio Transformers | Yes (Carnhill input, Edcor output) |
| Input Impedance Balanced |
300 Ω (Carnhill transformer) or 1 MΩ (Hi-Z instrument input) |
| Input Pad | −20 dB |
| Output Impedance Balanced |
600 Ω, Edcor transformer |
| Phantom Power | Yes |
| Operating Level | +4 dBu |
| Maximum Output Level | +22 dBu |
| Maximum Gain Reduction | 18 dB |
| Maximum Gain | 60 dB |
| Frequency Response | 20 Hz – 20 kHz ±0.3 dB |
| THD+N | <0.1% |
| Voltage | 115/230 V AC, 50–60 Hz |
| Power Consumption | 40 W |
| Power Supply | Internal |
| Dimensions | 70 × 50 × 30 cm |
| Shipping Weight | 7 kg |
| VU Meters | Yes, output level |
| Tube Set | 6N1P, 6N2P |
