8brain@... wrote:
into low audio rates.
really flatten it out to almost nothing - not the sort of effect every one
is after, though of use in some instances. In the last one I built, like
you, I went to .22uf when I accidently purchased 1M pots.
the LED voltage drop, though I needed to run several at once, and the chip
from which I was driving them was getting too hot. It may be fine with one
LED per chip, but using a quad op-amp and driving two LEDs is not
recommended. I abandoned them in favor of a transistor wired as an emitter
follower, running from a special power rail set at -2.2V to bias the LED to
start glowing at just above 0 Volts. The advantage of the circuit you've
listed though is if you use a bi-color LED (of the back to back two - leaded
package type) you should have a LED that lights green for positive levels
and red for negative levels. That would be of no use in the Psucho though,
because its output remains above 0 all the time.
Ken
_______________________________________________________________________
Ken Stone sasami@...
Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>
>Tonight I finished my first psycho LFO. I made a fewI've done some extensive playing around with the Psycho LFO too.
>modifications:
>1)put a 1 meg pot on every oscillator, copying the circuit for the1 Meg pots, along with 4k7 fixed series resistors give a range that goes up
>lowest one on the schematic. This provides a great deal of
>variety.
into low audio rates.
>2)I found the 1meg pot/2.2uF to provide too much slew, so I2.2uf really needs 100k pots. I explain that in the text. The 1 meg lets you
>changed the cap to .22 uF.
really flatten it out to almost nothing - not the sort of effect every one
is after, though of use in some instances. In the last one I built, like
you, I went to .22uf when I accidently purchased 1M pots.
>3)Added an LED, plus an LED driver that's probably overkill.I tried a similar arrangement on one, and it did work, nicely cancelling out
>(That's what I get for hanging out on the MOTM mailing list.)
>Schemo is here:
the LED voltage drop, though I needed to run several at once, and the chip
from which I was driving them was getting too hot. It may be fine with one
LED per chip, but using a quad op-amp and driving two LEDs is not
recommended. I abandoned them in favor of a transistor wired as an emitter
follower, running from a special power rail set at -2.2V to bias the LED to
start glowing at just above 0 Volts. The advantage of the circuit you've
listed though is if you use a bi-color LED (of the back to back two - leaded
package type) you should have a LED that lights green for positive levels
and red for negative levels. That would be of no use in the Psucho though,
because its output remains above 0 all the time.
>I'm very happy with the module. It's a very interesting modulationGood to hear! We need more people to share their ideas and experiences here.
>source. Driving a VCO with the portamento turned up a bit and
>the oscillators going at different frequencies I get really cool
>pseudo arabic folk melodies. Hours of fun!
Ken
_______________________________________________________________________
Ken Stone sasami@...
Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>