vibrato

[WeAreAs1 at aol.com]

In a message dated 1/29/00 7:01:03 AM, you wrote:

<< I think there were some attempts to make BBD 
pitch shifters in the 1970's.>>

Yes, the MXR Pitch Transposer used BBD's.  I don't know if it cross-faded 
between two BBD's.  I'm pretty sure I have the schematics for it somewhere 
around here - I'll check and see how they did it.

There was a Roland unit that used the same technique to do its pitch 
shifting.  I can't remember the name or model number, but it was made during 
the 1980's, and it could do up to four separate harmony parts.  It also did 
(crappy) pitch-to-MIDI conversion.  It used digital delays instead of analog 
delays, but they were still being clock-modulated with variable ramp waves 
(unlike modern digital transposers which actually do waveform cutting and 
splicing).  It actually had four separate digital delay circuits in it - they 
were on four plug-in cards.  They used the same custom digital delay gate 
array chip that Roland used in all of their other 1980's delay units 
(SDE-3000, 1000, 2500, DD-2, DD-3, RDD-10, etc.)  It didn't cross-fade 
between two delay circuits, though.  It simply cross-faded back to the 
undelayed input signal during the retrace period.

Michael Bacich