MOTM

If it can be connected to the mono output of my several Hammond 
clones and it does its job (I'm interested in the Hammond chorus 
simulation while all additional features may be welcome of course) 
I'm more than interested and I'd take not less than three PCBs
Enrico Dibennardo (Sicily)


--- In motm@yahoogroups.com, "JH." <jhaible@...> wrote:
>
>  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.
>