Whichever, an error between each of photo coupler comes out. Experiments of my friend shows us that though there is errors, I can get the great sounds. But it's just a trial. the shape of curve is almost same. So triming brightness of LED will change the rate and it make them same. Or big error is at high value areas, so putting pots with parallel make errors small. But each plan needs pot for each stage. If you build 6stage then you need 6 pots. Can we tune them ?
One day, a menber of Japanese local bbs at Abe's site introduce this page.
It lools like Cds Cells are dancing around campfire. This method allow as to trim thier distance from LED it means we can trim resistance each of them.
I want use big LED that I saw the local electrical shop. So I buy it.
I use NPN/PNP matched pair anti log method based on ARP style. I use no match one and don't use TC. But it works fine. there already is so big drift in CdS Cell. so it's enough for this circuits, I think.
I build them and take a picture and I turn it on, then LED was burn. That's the end. I mistake to put NPN and PNP. There is no stock for another Big LED. So I put the blue high brightness LED.
The raw data at the previous page is gotten from this schematics. and it Input voltage vs. resistance.
it's so bright. And there is no matter about the sensivity about the color. it's too bright.I move CdS Cell many times but I cant get matching with them.
At last I know. What ever do about this, We can't get matching from them
Buiding a phase shifter, at last
The core of phase shifter is the value of resistor and capacitor at the single shifter. CdS Cell is dynamic resister and capaciter is fixed.
I use 6 stages .And I use my CdS Cell as under 50K. So 0.022uF will determin the loest frequency
I had so many experiments but if you try re-experiments this, you should have to know the highest value of CdS Cell in usual use. It will lead you to the value of capacitor in most few steps. And next get bright LEDs.
schematics consists phase shift stage and input mixer for feed back and out put mixer for mix the orginal sound and shifted one.
and if you add them it's going to be twice levels. so input mixer had 1/2 atteneutor. this will make output level same as input.
I use these software for windows it's free to use but great!
I feel that I need more lightness! Big LED is provies light all CdS cell, but it's not enough to drive them so low resistance. The difference between green one and orange one are so small. So I use high bright red LED.
Self tuning is the most big charm point for D.I.Y. but, I know that we don't know what's the best setting is.
at first, you sould better to try the center dip to 1kHz or so. It's good start point for you. In my experiments, the voltage brings it to 1k is 7.85V in case of big LED and 4.79V for High bright red LED.
another LED can't light when CV input is 0V.But bule and white LED can light in so small current. and it rise the resistance of CdS Cell. So we don't need inital tune pot for CV inputs. We can use 0-15V in full range.
the voltage brings cf to 1k is 1.92. Just high area is good to use, I think.