Navicat Posted February 6, 2015 Report Share Posted February 6, 2015 (edited) This is a resistor ladder on a Dout module that can produce Controlable Voltage that midibox sequencers can handle ;; DOUT 160k ;; D7 ---o---/\/\/\---* ;; 80.6k | ;; D6 ---o---/\/\/\---* ;; 40.2k | ;; D5 ---o---/\/\/\---* ;; 20.0k | ;; D4 ---o---/\/\/\---* ;; 10.0k | ;; D3 ---o---/\/\/\---* ;; 5.1k | ;; D2 ---o---/\/\/\---*----CV Out-----------------------------------o ( 0v <----> +5v ) ;; 220 Ohm ;; D1 ---o---/\/\/\--------o free assignable trigger ;; 220 Ohm ;; D0 ---o---/\/\/\--------o another free assignable trigger __________________________________________________________________________ What i wanna ask here is.. How can i use a shift register with a resistor ladder as that.. but with higher voltages.. i need to go from 0 to +15v I need to use a different from 74HC595 that DOUT uses or is there another way? I saw something similar before but i am not so sure.. maybe a TL074 can do the job like that in this image: Regards, Tilemachos Edited February 6, 2015 by Navicat Quote Link to comment Share on other sites More sharing options...
latigid on Posted February 6, 2015 Report Share Posted February 6, 2015 Maybe this helps? http://www.ucapps.de/mbhp_aout_lc.html Quote Link to comment Share on other sites More sharing options...
Navicat Posted February 6, 2015 Author Report Share Posted February 6, 2015 Thank you for your answer! I know about Aout_LC and is really similar to that i want! But i need something different and i am really sorry i did not explain! What i wanna build is a module with with up to 8 CV channels that i will use to control the velocity on a TR-808 clone... Velocity on a TR-808 is a Trigger pulse of 1ms width with voltage from +5 and +15 Here is my idea taken from another project.. will this work? Quote Link to comment Share on other sites More sharing options...
Imp Posted February 6, 2015 Report Share Posted February 6, 2015 To get higher voltage, you need to configure the tl074 for some gain. You do this by adding a voltage divider to the feedback loop of the op-amp. eg. 20k between output and "-" and 10k between "-" and GND. If you don't need those pulses at the same time, this could work. You need to feed A and B with address bits, though. C can stay low, since you only use 4 Outputs. Quote Link to comment Share on other sites More sharing options...
Navicat Posted February 7, 2015 Author Report Share Posted February 7, 2015 You mean this?? http://www.falstad.com/circuit/e-amp-noninvert.html Quote Link to comment Share on other sites More sharing options...
Imp Posted February 7, 2015 Report Share Posted February 7, 2015 That's what i meant. Do you need any voltages between +5 and +15, or just those two values? If it's just 5V and 15V, there is an easier soulution: You could use two DOUT pins per instrument, one going directly to the trigger-in and another going to a ULN2803 or similar, so it gets amplified to 15V and then to the trigger-in. Quote Link to comment Share on other sites More sharing options...
Navicat Posted February 7, 2015 Author Report Share Posted February 7, 2015 Thank you very much for help me understand this!!! No i need any voltages between 0 and 15 volts with as much as high resolution i can get.. but 8-bit is ok!! Here is an example!! Thanks for your help! 0 volts in = 0 volts out 1 volts in = 3 volts out 3 volts in = 9 volts out 3.5 volts in = 10.5 volts out until i go up to 5 volts in = 15 volts out That's amazing!!! Regards Tilemachos Quote Link to comment Share on other sites More sharing options...
Navicat Posted February 7, 2015 Author Report Share Posted February 7, 2015 Is this right or i have mistakes in my schematics?? should there be a +15v supply in the op-amp or not? Quote Link to comment Share on other sites More sharing options...
Imp Posted February 7, 2015 Report Share Posted February 7, 2015 This has a gain of 1.5, to get a gain of 3 2k and 1k have to be switched. Since the op-amp will never have to put out negative voltages, you could connect its negative supply to gnd instead of -15V. You will need a little more than +15V on the positive supply, because else the op-amp can't reach +15V on its output. Quote Link to comment Share on other sites More sharing options...
Navicat Posted February 7, 2015 Author Report Share Posted February 7, 2015 Understand! That's cool!! Thank you very very much! That's a nice forum :hyper: :hyper: :hyper: Quote Link to comment Share on other sites More sharing options...
Navicat Posted February 7, 2015 Author Report Share Posted February 7, 2015 Ok man now i am sure that it will work! The same thing i'm trying to do is used in the TR-909 circuit! You are really amazing you answered as roland did it in the past! Take a look! Quote Link to comment Share on other sites More sharing options...
Imp Posted February 7, 2015 Report Share Posted February 7, 2015 Nah, that's just how it's done. Nothing special. Quote Link to comment Share on other sites More sharing options...
Navicat Posted February 11, 2015 Author Report Share Posted February 11, 2015 Ok i made a schematic for an 8x CV OUT and i need verification.. The R-2R ladder values are 20k and 10k. One more thing i wanna ask is.. Can i drive J19 on mbhp_core_stm32f4 to work as the J8/9 and connect more Dout and DIN chain? Here is the schematic for my DOUT with DAC and op-amps to get signal up to +15V : http://www.docdroid.net/ri8z/dout-cv.pdf.html Regards Tilemachos Quote Link to comment Share on other sites More sharing options...
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