Sony Yeds18 Test Disc Exclusive ((better)) Official

: The disc was never intended for public sale. Its exclusivity stems from its role as "not for sale" service equipment, though limited pressings have surfaced over decades. Market Value

By combining two distinct frequencies (e.g., 60 Hz and 7 kHz) on a single track, the YEDS-18 allows engineers to test for intermodulation distortion. High-quality players will reproduce both tones cleanly without creating artificial "ghost" frequencies where the two waves interact. 3. Channel Separation and Phase Tests sony yeds18 test disc exclusive