“Audio-GD Current Signal System“ (ACSS) technology. ACSS technology offers the least colored, most detailed and neutral sound. Audio-GD Current Signal System“ (ACSS) technology. ACSS technology offers the least colored, most detailed and neutral sound. It avoids the noise and distortions created from the use of multiple voltage gain stages. When you operate an ACSS system, you will hear improvements in any aspect of the sound stage to deliver best musical performance.