OKKO Dominator [traced]
- euronymous0001
- Breadboard Brother
i spot some mistakes on the component labels
Hello everyone and sorry for my bad English.
On our forum we have been following this interesting discussion and we design a layout on a single-side with only 4 bridges, it uses a TLC2272 instead of two TL072.
Plus I think it is much more versatile replace the switch for the mid range with a potentiometer. If I understand how it works should be an on / off / on that parallels the 1M resistor with the other two to be precise cuts;it could be replaced with a 1M potentiometer with a 10k resistor in series i think.
Last question: what value C6? 100pF 100nF or?
here's the schematic
and the eagle files
On our forum we have been following this interesting discussion and we design a layout on a single-side with only 4 bridges, it uses a TLC2272 instead of two TL072.
Plus I think it is much more versatile replace the switch for the mid range with a potentiometer. If I understand how it works should be an on / off / on that parallels the 1M resistor with the other two to be precise cuts;it could be replaced with a 1M potentiometer with a 10k resistor in series i think.
Last question: what value C6? 100pF 100nF or?
here's the schematic
and the eagle files
- roseblood11
- Tube Twister
Thanx for posting, but I can´t see the Image...
Could you please post the layout as GIF and a scaled pnp file?
Not everybody has EAGLE Cad (but this would definitely be a reason to install the freeware version)
Could you please post the layout as GIF and a scaled pnp file?
Not everybody has EAGLE Cad (but this would definitely be a reason to install the freeware version)
- roseblood11
- Tube Twister
Does the voltage supply really work properly? How much voltage do you get out of the 7660S? With 1n400x diodes, it´s not much more than 16V, I guess? Can the 7815 work correctly with that input voltage? The datasheet says: "input voltage required to maintain line regulation: 17,7V) I´d suggest to use schottkys (1n5817 or similar) for D1 and D2...
my fault , i didn't update this value
here's the projects updates, i can't delete the old files....
here's the projects updates, i can't delete the old files....
- Attachments
-
- okko dominatrix.rar
- okko dominator with TLC2274 and midrange pot control
- (406.77 KiB) Downloaded 896 times
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- okko dominator.rar
- okko dominator with TLC2274
- (384.93 KiB) Downloaded 783 times
- roseblood11
- Tube Twister
That schematic shows the tlc2274 again... I wonder if that´s really a good choice here, because its max voltage rating is 16V. If the voltage doubler is build with 1n4004 diodes, it will deliver slightly more than 16V, and even more than 17V if schottky diodes are used.
- guiddruid
- Breadboard Brother
It seems completely pointless to run some of the opamps off the unregulated supply anyway. I would be suprised if it were possible to clip those inputs, given the amount of attenuation following the distortion stage.
here's the latest version 1.2
-i've changed the IC2 supply from Vb to Va so the supply of IC1 and IC2 is the same, i don't understand what kind of problem can introduce R38
who had already made pcb with previous old versions can easily replace the TLC2274 with the TL074 without change anything
-i've changed the IC2 supply from Vb to Va so the supply of IC1 and IC2 is the same, i don't understand what kind of problem can introduce R38
-updated the charge pump diodes with schotty type (i'll try it Roseblood)guiddruid wrote:Probably better going the other end of R38 - I assume that resistor is there to affect the distortion stage.
who had already made pcb with previous old versions can easily replace the TLC2274 with the TL074 without change anything
- Attachments
-
- okko dominatrix V1.2.rar
- Okko dominatrix latest version
- (333.11 KiB) Downloaded 949 times
- roseblood11
- Tube Twister
That´s a little to quick...
Will the 7815 work properly, if it has to deliver that much current? Remember my question from a few days ago:
Or maybe it´s a part of the sound that the power supply is a bit weak? Someone should measure that under working conditions
(Voltage at the output of the 7660S and the 7815)
Will the 7815 work properly, if it has to deliver that much current? Remember my question from a few days ago:
Even with schottkys you won´t get 17,7V out of the 7660S... Maybe the configuration in the original Okko pedal only works, because the 7815 dosn´t have to deliver much current?Can the 7815 work correctly with that input voltage? The datasheet says: "input voltage required to maintain line regulation: 17,7V)
Or maybe it´s a part of the sound that the power supply is a bit weak? Someone should measure that under working conditions
(Voltage at the output of the 7660S and the 7815)
- guiddruid
- Breadboard Brother
Standard linear regulators have a dropout voltage (=minimum value of vout-vin) that's around 1.7 at full load - it's a little less at lower output currents, but still over a volt.
The charge pump will output at most (0ma load) 2*(9V - diode drop). With magic diodes and no load you would be at 18v. Take two diode drops off that, and you are at most at 17.4 for schottkys, or 16.8 for ordinary signal diodes. Add any load current, and it's looking dodgy.
roseblood11 is probably correct that the regulator may well start dropping its output below 15V (and therefore letting charge pump noise through) with the tone control opamps connected.
Replacing the standard 15V regulator with an "ultra low dropout" type should sort that - they can go down to about 300mV dropout.
Powering the tone opamps through R38 would mean that any variations in the current drawn in the distortion opamps will be seen on the power rail of the tone opamps. It's possible the current varies quite a bit, when the distortion opamp is distorting. Connect the tone opamps straight to the output of the (LDO) regulator, and you don't have to worry about that.
The charge pump will output at most (0ma load) 2*(9V - diode drop). With magic diodes and no load you would be at 18v. Take two diode drops off that, and you are at most at 17.4 for schottkys, or 16.8 for ordinary signal diodes. Add any load current, and it's looking dodgy.
roseblood11 is probably correct that the regulator may well start dropping its output below 15V (and therefore letting charge pump noise through) with the tone control opamps connected.
Replacing the standard 15V regulator with an "ultra low dropout" type should sort that - they can go down to about 300mV dropout.
Powering the tone opamps through R38 would mean that any variations in the current drawn in the distortion opamps will be seen on the power rail of the tone opamps. It's possible the current varies quite a bit, when the distortion opamp is distorting. Connect the tone opamps straight to the output of the (LDO) regulator, and you don't have to worry about that.