Slagle AVC

About the Slagle AVC

The Slagle AVC (Autoformer Volume Control) is a passive preamplifier volume control designed by Dave Slagle and produced by Bent Audio. It uses custom autoformer modules, known as 'Slagleformer Modules,' which provide precise volume attenuation in 1.25 dB steps over a wide range, from +1.25 dB to -41.25 dB in 32 steps. The design employs two discrete rotary switches to achieve fine control, with one switch offering 12 positions in 3.75 dB increments and the other providing 3 positions for ±1.25 dB adjustments. This dual-switch approach allows for smooth and accurate volume control without the use of resistive parts or power supplies, preserving signal purity. The unit is highly regarded for its transparency, natural sound, and ability to showcase upstream components without coloration. It is often used in DIY audio projects and pairs well with tube amplifiers. The AVC-1 model features bandwidth from below 10 Hz to over 100 kHz with very low distortion (<0.0008%), and channel matching is very close. The device is available in stereo and mono versions, with options for copper or silver winding in the autoformers. The Slagle AVC is considered a top-tier passive preamp volume control favored by audiophiles seeking minimal signal degradation and excellent dynamic performance.