Standard Audio Level-Or Mk2 DUAL 2-Channel Limiter/Harmonic Processor

The Standard Audio Level-Or Mk2 DUAL brings the classic JFET limiter and Class-A harmonic distortion circuit of the 500-series Level-Or Mk2 into a 2-channel 19-inch rack format, adding stereo and serial processing capabilities not available in the single-slot module. The same three operating modes—LEVEL (high-ratio JFET feedback limiting), CRUNCH (discrete Class-A transistor harmonic distortion), and BYP (true relay bypass)—are present on each channel, now joined by a LINK switch that configures both channels for stereo sidechain-linked compression, fully independent operation, or CASCADE mode, which routes Channel 1’s output to Channel 2’s input for dual-stage serial processing on a single mono source. A MIX control on each channel blends the processed and dry signals for parallel compression or distortion, and a low-noise internal linear power supply accepts universal voltage input via a standard IEC connector.

Key Features

• LEVEL mode — high-ratio JFET feedback limiter with selectable release time (Fast / Med / Slow via SPEED switch); MODE LED illuminates green
• CRUNCH mode — multiple discrete Class-A transistor stages generate harmonic distortion; SPEED switch sets output LPF: Fast (disabled) / Med (15kHz) / Slow (8kHz) for shaping higher-order harmonics; MODE LED illuminates red
• BYP mode — true relay bypass; MODE LED off; DI input passes clean signal with output level control via OUTPUT pot
• LINK switch — S/C LINK mode — links both channel sidechains for stereo operation in LEVEL mode, reducing stereo image shift during gain reduction
• LINK switch — IND mode — both channels operate fully independently
• LINK switch — CASCADE mode — routes Channel 1 output internally to Channel 2 input for dual-stage serial processing on a single mono signal path
• MIX pot (per channel) — blends processed (wet) and original (dry) signals for parallel compression or distortion; fully clockwise = 100% processed
• 1/4″ DI input (per channel) — instrument-level input auto-detected on plug insertion; passes clean signal in BYP mode with output level control
• GR/THD LEDs (x3 per channel) — indicate amount of gain reduction (LEVEL mode) or harmonic distortion (CRUNCH mode)
• XLR inputs and outputs (rear panel) — line-level, gold-plated pins
• Ground lift switch — lifts chassis ground (XLR Pin 1) on input connectors to address ground loops
• Internal linear power supply — low-noise, stable voltage; universal input 85–240VAC at 50–60Hz via standard IEC connector
• 19-inch rackmount chassis — rugged steel and aluminum construction

Specifications

• Format: 2-channel 19-inch rack unit
• Operating Modes (per channel): Level (JFET limiter), Crunch (harmonic distortion), Bypass (true relay)
• Compression Type: High-ratio JFET feedback limiter (Level mode)
• Distortion Type: Discrete Class-A transistor harmonic distortion (Crunch mode)
• Release Time (Level mode): Fast / Med / Slow
• Output LPF (Crunch mode): Disabled / 15kHz / 8kHz
• Channel Link Modes: S/C Link (stereo), Independent, Cascade (serial mono)
• Audio Inputs: XLR (line, rear panel, gold-plated); 1/4″ DI (instrument, front panel, auto-detect)
• Audio Outputs: XLR (line, rear panel, gold-plated)
• Ground Lift: Toggle switch, per input (XLR Pin 1)
• Bypass: True relay bypass (per channel)
• Power Supply: Internal linear; universal input 85–240VAC, 50–60Hz; IEC connector
• Controls: Input, Output, Mix (pots); Mode, Speed (toggle switches); Link (toggle switch)
• Indicators: MODE LED (green/red/off); GR/THD LEDs ×3 per channel