Anyone have 'stereo blend' control experience?


I'm interested in any details anyone may be able to provide concerning 'stereo blend' controls, for progressivly reducing a 2-channel signal down from full separation towards a mono blend, presumably through cross-mixing.

What older equipment might you be familiar with that featured such a contol? Did any incorporate a 'defeat' provision, or was the control always in the circuit? If you ever used one, how well do you remember it working?

Do you have any electrical design knowledge of previous implementations of this idea, or suggestions on how to make one? What kinds of parts were used in any older designs you may have seen? Do you know of any schematics?

I realize this probably was a pretty obscure feature even in its day, but maybe some of you more, ahem, experienced hands out there know what it is I'm talking about. TIA for any info!
zaikesman
Not obscure at all Z man. The Dyna Pas features a four position stereo blend control. I found it useful on older jazz recordings that were mixed with instruments hard left and hard right with a hole in the middle. I better shuttup before mentioning the great Rudy Van Gelder as being guilty of this sin. A lot of early stereo recordings wanted to show off the characteristics of the medum and so there were a lot of weird mixes (as if there aren't today). In the end though I just reach for the mono button; mono listening avoids all of these distractions. Good luck.
My long gone Dynaco PAT4 preamp had stereo blend but I can't remember exactly what it was for. Maybe for their three speaker with center channel application that was supposedly specially suited to the Dynaco A-25 speakers. Whenever I used it in two channel I had the eerie feeling it was neither stereo nor mono and that made it seem strange. It wasn't progressive, just on or off. I'll betcha somebody has the circuit diagram for a PAT4 and the directions for building one underneath a pile of old stereo reviews. Good luck in your search.