Scanner Chorus pcb interest?
2007-07-06 by JH.
Thinking about future pcb projects ...
One thing I wanted to do for a long time is a stereo chorus based on my
electronic emulation of the Hammond Scanner Vibrato.
I've built something like that a few years ago:
http://jhaible.heim.at/scanner_vibrato/jh_scanner_vibrato.html
This was purely intended to be an emulation of the Hammond Chorus/Vibrato
effect, but I always thought it would also make an interesting, more
general, and stereo, chorus device.
That would be a "true analogue" chorus in a different sense than the
BBD-based effects, because the signal is not sampled.
It's not free of side effects, thou. It has a somewhat rough modulation
waveform, as instead of changing a delay time continuously, it interpolates
between 9 taps of a 1ms analogue delay line. It's a linear interpolation,
not a switching - best thing is you listen to the sound samples and decide
for yourself. It's very rough (in a Hammond-ish way!) for vibrato, and
increasingly smoother when the dry signal is mixed in for chorus.
It's a quite complicated method to crate a simple chorus, compared to a BBD
circuit. It requires a 50-pole (fifty!) low pass filter, but that can easily
be built from 25 cheap inductors (less than a dollar per piece at Mouser)
and 25 capacitors.
On the positive side, it's a lot more "direct" sounding than a BBD-based (or
digital delay based) chorus, as the maximum delay time thru the whole
circuit is only 1ms. (Speak of latency ...)
If there's enough interest, this could be a project for a future PCB
development. I wouldn't restrict this to Hammond emulation, but make a
mono-in / stereo out device in the fashion of many Roland / Boss dual-BBD
chorus circuits. Just without BBD. Let me know what you think ...
JH.
PS: this is not to be confused with my Interpolating Scanner, which is
planned to be a future MOTM module.
One thing I wanted to do for a long time is a stereo chorus based on my
electronic emulation of the Hammond Scanner Vibrato.
I've built something like that a few years ago:
http://jhaible.heim.at/scanner_vibrato/jh_scanner_vibrato.html
This was purely intended to be an emulation of the Hammond Chorus/Vibrato
effect, but I always thought it would also make an interesting, more
general, and stereo, chorus device.
That would be a "true analogue" chorus in a different sense than the
BBD-based effects, because the signal is not sampled.
It's not free of side effects, thou. It has a somewhat rough modulation
waveform, as instead of changing a delay time continuously, it interpolates
between 9 taps of a 1ms analogue delay line. It's a linear interpolation,
not a switching - best thing is you listen to the sound samples and decide
for yourself. It's very rough (in a Hammond-ish way!) for vibrato, and
increasingly smoother when the dry signal is mixed in for chorus.
It's a quite complicated method to crate a simple chorus, compared to a BBD
circuit. It requires a 50-pole (fifty!) low pass filter, but that can easily
be built from 25 cheap inductors (less than a dollar per piece at Mouser)
and 25 capacitors.
On the positive side, it's a lot more "direct" sounding than a BBD-based (or
digital delay based) chorus, as the maximum delay time thru the whole
circuit is only 1ms. (Speak of latency ...)
If there's enough interest, this could be a project for a future PCB
development. I wouldn't restrict this to Hammond emulation, but make a
mono-in / stereo out device in the fashion of many Roland / Boss dual-BBD
chorus circuits. Just without BBD. Let me know what you think ...
JH.
PS: this is not to be confused with my Interpolating Scanner, which is
planned to be a future MOTM module.