DiademTone DT-2A (LA-2A Style Opto Comp)

Hand-Assembled · 3-Year Warranty Every Diadem Tone unit is hand-assembled one at a time using carefully selected components, and is individually quality checked before it leaves the factory. That's why Diadem Tone backs every product with a 3-year warranty. Diadem Tone DT-2A Optical Tube Compressor Some compressors grab. The DT-2A glides. It is a single-channel optical valve leveling amplifier built on the classic 2A architecture, delivering the smooth, natural gain reduction and valve warmth that have made this style of compressor a studio staple for decades. At its heart is Diadem Tone's own enhanced DT-T4 optical cell, designed for extended high-frequency response and exceptionally smooth compression. Four valves carry the signal: two 12AX7s for gain and harmonic texture, a 12BH7 for robust, low-distortion drive, and a 6AQ5 that adds thickness and warmth at the output. Careful circuit design and component selection give it a noise floor of -90 dB, so it stays clean even at high gain. What the DT-2A Recreates The LA-2A leveling amplifier appeared in the early 1960s and is one of the most recognisable compressors ever made. Rather than a transistor, it uses an optical cell: a light source and a light-sensitive resistor inside a sealed module. As the signal gets louder, the light glows brighter and the resistor turns the level down. That optical process reacts in a naturally smooth, program-dependent way. It has a fixed 10 ms attack and a two-stage release, recovering the first half of its gain reduction in about 60 ms and the rest over 0.5 to 5 seconds, depending on what you feed it. Why Engineers Still Reach for It The 2A is loved because it is both musical and simple. There are really only two knobs: Peak Reduction sets how much it compresses, and Gain sets the output. Yet the results sound polished almost instantly. The optical cell never clamps down harshly. It gently levels a performance so it sits consistently in the mix, while the valve stages add a warmth and density that make sources sound finished. What to Use It On Vocals – its signature application. Smooth, transparent leveling that keeps a vocal present without sounding squashed. For the classic combination, follow a DT-76: the FET catches the fast peaks, and the DT-2A evens out the overall level. Bass – holds bass guitar and synth bass steady and full, with valve weight in the low end. Acoustic instruments – acoustic guitar, piano and strings get gentle control that preserves their natural dynamics. Buses and stems – light gain reduction on a vocal or instrument group glues parts together without obvious pumping. Tracking – its forgiving response makes it a safe, great-sounding choice to record through. A fast FET compressor and a smooth optical compressor are two of the most useful tools any studio can own, and each does what the other can't. The DT-2A brings genuine optical compression and a four-valve signal path to your rack, with the hands-on simplicity that lets you set it by ear and get back to the music. Front Panel Gain – sets the output level Peak Reduction – sets the amount of compression Compress / Limit switch – selects compression or limiting mode R37 – trim adjustment Meter – VU meter switchable between Gain Reduction, Output +10 and Output +4 Power switch Specifications Type Single-channel optical valve compressor Optical Cell Diadem Tone enhanced DT-T4 Valves 2 × 12AX7, 1 × 12BH7, 1 × 6AQ5 Attack Time 10 ms Release Time 0.06 s for 50% release; 0.5 to 5 s for complete release Gain 40 dB Frequency Response 15 Hz to 20 kHz Total Harmonic Distortion < 0.5% Noise Floor -90 dB ±5 Input Level +16 dB Output Level +10 dB nominal, +16 dB maximum Input Impedance 600 Ω (balanced) Output Load Impedance 600 Ω (balanced) Connections XLR Power 115 / 230 VAC, 50–60 Hz Size 19″ rackmount, 3U Weight 5.5 kg Warranty 3 years LA-2A is a trademark of its respective owner and is referenced for descriptive purposes only.