FWIW: I owned the B&K EX140, which I guess are pretty rare at this point. They were a dual-mono version of the ST140. Same chasis. Looked identical to an early ST140 with the only exterior difference being the label. I did a lengthy comparison between the two at the time with all kinds of music (mid 1980's) and ended up prefering the EX140. That was a long time ago so don't ask me why I liked the EX better! It served me well for nearly 12 years of constant use, and was still working well and sounding pretty darn good when I sold it.
Marco
Marco