A Designs 503HR 3-slot 1U chassis in excellent condition. High-quality external universal power supply minimizes noise. * High-end 1U x 3-slot, usable as a convenient studio rack mount or portable channel strip * Excellent condition, with some minor rack scratches on the top and bottom * No scratches or marks on the faceplate * 100% reliable, noise-free operation * Professionally modified in 2025 to accommodate full-box modules (photo 8) * Used only in a smoke-free home studio * Includes one Radial blank plate Technical Specifications and Features * 3-slot 500 series chassis * High-quality external universal power supply fully supplies the necessary power and minimizes power supply noise * Internal routing switch with multiple configurations: * All 3 slots independent * Slot 1 → Slot 2 direct feed (Slot 3 solo) * Direct chain connection of slots 1-3 without cables * Three LED power status indicators (+16V, -16V, 48V) * Professional modification in 2025 allows proper accommodation of full-box modules as well as flat board types (see photos) * Previously tried three different chassis, all of which had problems either not supplying enough power to certain units or producing noticeable signal noise. This unit has none of those problems and is 100% reliable and noise-free. Ideal for engineers and producers who need a reliable and flexible 500 series chassis with excellent power supply and routing options. Selling because I am reorganizing my studio equipment as I am now working solo. Please feel free to ask if you have any questions!