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Have a request of the gurus in here. I have needs for a relatively cheap OSC (sine) that can be varied from zero to approx. maybe 20 cycles continuously.
Here is a link to a simple circuit for producing a tremelo effects
pedal which involves a LFO. Bear in mind, though, that to get a true
Leslie sound requires reproducing a slight Doppler effect on the sound
caused by the spinning rotors.
http://www.instructables.com/id/Make-Your-Own-Tremolo-Effects-Pedal/
Thanks. That has some good possibilities and it's real cheap to implement. The Doppler will be implemented via steering said LFO to slightly vary filtering as well as some panning and tremolo. I can see phase, freq. and amplitude changes would all be involved with a Leslie so I am trying to replicate it as closely as possible electronically.
On Tue, 21 Oct 2014 10:13:42 -0700 (PDT), "Ron M."
strmbrgr2@hotmail.com> wrote:
Have a request of the gurus in here. I have needs for a relatively cheap OSC (sine) that can be varied from zero to approx. maybe 20 cycles continuously. Been busting my brain to implement it. This is for a source into a keyboard to act as a Leslie. Any ideas guys. THANKS.
On Tue, 21 Oct 2014, Ron M. wrote:
Have a request of the gurus in here. I have needs for a relatively cheap
OSC (sine) that can be varied from zero to approx. maybe 20 cycles
continuously. Been busting my brain to implement it. This is for a
source into a keyboard to act as a Leslie. Any ideas guys. THANKS.
I think it's all done digitally now.
Those are really low frequencies, made worse since you say you need it to
go down to zero. Obviously not, but still I can see why you want a slow
rate, and that will make things complicated, big value resistors and
capacitors, and maybe problems gettting down that low with one turn of the
knob.
Why not a stepped sinewave? WOuld that be good enough? You use a ripple
counter, and some weighted resistors, and you get a stepped sinewave that
persumably is easier to filter out the imperfections. Since you will be
dividing the oscillator frequency in the ripple counter, the oscillator
can be at a higher frequency, making a wider range easier, and the
component values more manageable.
And speaking of imperfect sinewaves, things like the Intersil 8038 and
Exar 2206 generated a triangle wave, and used diode shaping to get
sinewaves. You wouldn't want it for testing distortion somewhere, but
perhaps that's good enough for this purpose. Though, you are then back to
large value capacitors for a very low frequency oscillator, but at least
the oscillator is an RC one.
Michael
Have a request of the gurus in here. I have needs for a relatively cheap
OSC (sine) that can be varied from zero to approx. maybe 20 cycles
continuously. Been busting my brain to implement it. This is for a
source into a keyboard to act as a Leslie. Any ideas guys. THANKS.
I think it's all done digitally now.
On Tuesday, October 21, 2014 2:00:38 PM UTC-5, d...@yipee.com wrote:
Here is a link to a simple circuit for producing a tremelo effects
pedal which involves a LFO. Bear in mind, though, that to get a true
Leslie sound requires reproducing a slight Doppler effect on the sound
caused by the spinning rotors.
http://www.instructables.com/id/Make-Your-Own-Tremolo-Effects-Pedal/
Thanks. That has some good possibilities and it's real cheap to implement. The Doppler will be implemented via steering said LFO to slightly vary filtering as well as some panning and tremolo. I can see phase, freq. and amplitude changes would all be involved with a Leslie so I am trying to replicate it as closely as possible electronically.
On Tue, 21 Oct 2014 10:13:42 -0700 (PDT), "Ron M."
strmbrgr2@hotmail.com> wrote:
Have a request of the gurus in here. I have needs for a relatively cheap OSC (sine) that can be varied from zero to approx. maybe 20 cycles continuously. Been busting my brain to implement it. This is for a source into a keyboard to act as a Leslie. Any ideas guys. THANKS.
On Tuesday, October 21, 2014 6:47:17 PM UTC-5, Michael Black wrote:
On Tue, 21 Oct 2014, Ron M. wrote:
Have a request of the gurus in here. I have needs for a relatively cheap
OSC (sine) that can be varied from zero to approx. maybe 20 cycles
continuously. Been busting my brain to implement it. This is for a
source into a keyboard to act as a Leslie. Any ideas guys. THANKS.
I think it's all done digitally now.
Those are really low frequencies, made worse since you say you need it to
go down to zero. Obviously not, but still I can see why you want a slow
rate, and that will make things complicated, big value resistors and
capacitors, and maybe problems gettting down that low with one turn of the
knob.
Why not a stepped sinewave? WOuld that be good enough? You use a ripple
counter, and some weighted resistors, and you get a stepped sinewave that
persumably is easier to filter out the imperfections. Since you will be
dividing the oscillator frequency in the ripple counter, the oscillator
can be at a higher frequency, making a wider range easier, and the
component values more manageable.
And speaking of imperfect sinewaves, things like the Intersil 8038 and
Exar 2206 generated a triangle wave, and used diode shaping to get
sinewaves. You wouldn't want it for testing distortion somewhere, but
perhaps that's good enough for this purpose. Though, you are then back to
large value capacitors for a very low frequency oscillator, but at least
the oscillator is an RC one.
Michael
Ideally it would start from zero and ramp up to speed and then slow back to zero upon turn off. Then while on it needs to be somewhat variable as a real Leslie is. The Leslie being mechanical has a lag when started and momentum when stopped. Would love to replicate that effect instead of a constant speed. Not seeing an easy way to do the speed up/down without overly complicating the thing. However being able to continuously vary the speed and turn it on and off would be key.
Have a request of the gurus in here. I have needs for a relatively
cheap OSC (sine) that can be varied from zero to approx. maybe 20
cycles continuously. Been busting my brain to implement it. This is
for a source into a keyboard to act as a Leslie. Any ideas guys.
THANKS.
On Tuesday, October 21, 2014 1:13:42 PM UTC-4, Ron M. wrote:
Have a request of the gurus in here. I have needs for a relatively cheap OSC (sine) that can be varied from zero to approx. maybe 20 cycles continuously. Been busting my brain to implement it. This is for a source into a keyboard to act as a Leslie. Any ideas guys. THANKS.
I've done a Wien bridge down to 3 Hz.
https://www.dropbox.com/s/lmso5zx69g2l1lc/DSCF0047.JPG?dl=0
You could push it to 1 Hz (maybe)
Or a stepped sine thing with square wave into a CD4017 and artfully chosen resistors on the output... into an opamp summer.
Could it be a triangle wave?
George H.
A Stanford paper called "Doppler Simulation and the Leslie"
https://ccrma.stanford.edu/~jos/doppler/doppler.pdf
On Tue, 21 Oct 2014 10:13:42 -0700 (PDT), "Ron M."
strmbrgr2@hotmail.com> wrote:
Have a request of the gurus in here. I have needs for a relatively cheap OSC (sine) that can be varied from zero to approx. maybe 20 cycles continuously. Been busting my brain to implement it. This is for a source into a keyboard to act as a Leslie. Any ideas guys. THANKS.
On Wednesday, October 22, 2014 11:07:38 AM UTC-5, George Herold wrote:
On Tuesday, October 21, 2014 1:13:42 PM UTC-4, Ron M. wrote:
Have a request of the gurus in here. I have needs for a relatively cheap OSC (sine) that can be varied from zero to approx. maybe 20 cycles continuously. Been busting my brain to implement it. This is for a source into a keyboard to act as a Leslie. Any ideas guys. THANKS.
I've done a Wien bridge down to 3 Hz.
https://www.dropbox.com/s/lmso5zx69g2l1lc/DSCF0047.JPG?dl=0
You could push it to 1 Hz (maybe)
Or a stepped sine thing with square wave into a CD4017 and artfully chosen resistors on the output... into an opamp summer.
Could it be a triangle wave?
Upon researching it further it appears that a triangle would probably in fact work close enough to be unnoticeable. I might have over analyzed it. Does make the design a whole lot easier. The ramp up also might be a little over kill. Went to an old friend who works on Hammonds and has a Leslie corrected me on that. It appears they have either off, slow and high speeds and the ramp up is purely a mechanical lag which I have determined is way more difficult to implement per some of the responses received. Thanks for all the help guys. Will let ya'll know what happens.
George H.
Have a request of the gurus in here. I have needs for a relatively cheap
OSC (sine) that can be varied from zero to approx. maybe 20 cycles
continuously. Been busting my brain to implement it. This is for a
source into a keyboard to act as a Leslie. Any ideas guys. THANKS.
On Tue, 21 Oct 2014 10:13:42 -0700, Ron M. <strmbrgr2@hotmail.com> wrote:
Have a request of the gurus in here. I have needs for a relatively
cheap OSC (sine) that can be varied from zero to approx. maybe 20
cycles continuously. Been busting my brain to implement it. This is for
a source into a keyboard to act as a Leslie. Any ideas guys. THANKS.
1. VCO that varies from 1kHz up to 1020Hz, as iput into an analog
multiplier with the other input 10kHz, don't recommend that though
2. 16 bit 1024 looped register [can be implemented in C/C++] containing
1024 digial values of a sinewave. Vary the shift clock from 0 to 20480.
Output into a DAC. Definitely continuous waveform.
no idea of the 'costs' for this compared to the reliability ot get
what you want.
1. VCO that varies from 1kHz up to 1020Hz, as input into an analog
multiplier with the other input 1kHz, don't recommend that though
Have a request of the gurus in here. I have needs for a relatively cheap OSC (sine) that can be varied from zero to approx. maybe 20 cycles continuously. Been busting my brain to implement it. This is for a source into a keyboard to act as a Leslie. Any ideas guys. THANKS.
On Tuesday, October 21, 2014 1:13:42 PM UTC-4, Ron M. wrote:
Have a request of the gurus in here. I have needs for a relatively cheap =
OSC (sine) that can be varied from zero to approx. maybe 20 cycles continuo=
usly. Been busting my brain to implement it. This is for a source into a ke=
yboard to act as a Leslie. Any ideas guys. THANKS.
I've done a Wien bridge down to 3 Hz.=20
https://www.dropbox.com/s/lmso5zx69g2l1lc/DSCF0047.JPG?dl=3D0
You could push it to 1 Hz (maybe)
Or a stepped sine thing with square wave into a CD4017 and artfully chosen =
resistors on the output... into an opamp summer. =20
Could it be a triangle wave? =20
George H.