The Convergent Audio Technology (CAT) SL-1 Signature MK2 is all about transparency. You’re not getting a preamp that colors your sound or adds unnecessary "character." Instead, you get a preamp that lets the music breathe and come through exactly as it was intended. If your system is high-end enough, this preamp will make it sound even better—but beware, if you’ve got weak links elsewhere, the SL-1 MK2 will expose them with surgical precision.

• Improved circuit-board construction: low-loss circuit-board material; thicker board; capacitors mounted with damping compound to reduce vibration
• Stronger main chassis: rigid beam welded inside bottom cover; thicker metal; U-shaped bracket for mounting circuit board (was L-shaped)
• New audio wire
• Visco-elastic shock mounts used to isolate transformer vibrations
• New power-supply cable is shielded and constructed with better wire and insulation
• New power-supply board: 10 times more audio supply capacitance; filter on audio supply to reduce input noise; filter for main regulator; buffer transistor greatly reduces current draw from the voltage reference (in the main preamp); nearly double capacitance in the three filament supplies; filtering of noise from filament regulators
• Thicker faceplate, without rack-mount slots

• Tested all inputs and outputs
• Tested all input and output connectors
• Cleaned and verified all controls operation
• All tubes test good
• Replaced power button lamp