
1981 - 1985.
Someone says (www.audio.com.hk) : "Some ML-6A are from Woodbridge assembled by the original Mark Levinson. Modifications to 6B were done by Kevin Burke in Middletown. I have the lucky chance of trying both 6A and 6B. Both are wonderful preamps except that 6A sounds more open with some transistor glare and 6B sounds more natural but less hi freq."