Vintage Klark Teknik DN504 Quad Compressor / Limiter - Professional 1U Rack Unit
Condition: Used – Excellent Working Order (Pro Audio Vintage Gear) Removed from professional recording studio.
Item Description
The legendary Klark Teknik DN504, a classic 4-channel (Quad) Compressor / Limiter built with high-grade British engineering. Housed in a compact 1U rack chassis, the DN504 is famous in professional studios and live touring rigs for its exceptionally smooth, transparent compression and bulletproof durability.
Whether you need precise dynamic control for drums, vocals, acoustic instruments, or stereo bus processing, this vintage unit delivers clean gain reduction without sacrificing tonal character.
Features & Key Highlights
4 Independent Channels: Compress up to 4 separate mono channels simultaneously in just 1U of rack space.
Stereo Link Functionality: Easily pair Channels 1+2 and Channels 3+4 for true stereo operation (Master/Slave configuration).
Switchable Knee Modes:
Soft Knee: Super smooth, transparent levelling for vocals, strings, and stereo mixes.
Hard Knee: Precise peak control and aggressive punch for drums, bass, or dynamic control.
Auto Attack/Release Mode: Intelligent program-dependent timing that automatically adapts to incoming signal dynamics.
Comprehensive LED Metering: 8-segment LED gain reduction and output level meters per channel.
Sidechain Inserts: Dedicated sidechain send/return jacks per channel for frequency-conscious compression (e.g., de-essing, ducking).
Pro Balanced Connectivity: Transformerless balanced XLR inputs and outputs.
Technical Specifications
| Parameter | Specification |
| Model | Klark Teknik DN504 |
| Type | Analog Quad Compressor / Limiter |
| Rack Size | 1U standard 19" rackmount |
| Inputs / Outputs | XLR (Balanced) |
| Sidechain Connections | 1/4" TRS Jack per channel |
| Threshold Range | -30 dBu to +20 dBu |
| Ratio Range | 1:1 to ∞:1 (Limiting) |
| Power Supply | Internal switchable AC (110V–240V) |
Condition Notes
Functional Condition: 100% fully tested and operational. All pots, buttons, XLR jacks, and LED meters work as intended with clean signal flow.
Cosmetic Condition: Good vintage condition. Marks around mounting holes and typical surface scratches on the top casing from normal rack installation (please inspect detailed listing photos). Front panel remains clean and readable.
Package Includes
Note to Buyers: Vintage analog pro audio gear of this caliber is becoming harder to find in great condition. Unit will be double-boxed and padded heavily for safe transport. All sales are final—please review images and ask any questions prior to bidding/buying.