mb_2069
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mb_2069 [2017/09/20 10:16] antichambre [Choices made during prototyping] |
mb_2069 [2017/11/08 12:10] (current) antichambre [Choices made during prototyping] |
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| ==== Precious information found about the 2069 once prototyped ==== | ==== Precious information found about the 2069 once prototyped ==== | ||
| - | <WRAP center round info 60%> | + | <wrap info>The Absolute Rating Voltage is +/-5V, tried and fried ;)</wrap>\\ |
| - | The Absolute Rating Voltage is +/-5V, tried and fried ;)\\ | + | <wrap info>CV inputs are in a 0 to 5V range.</wrap>\\ |
| - | </WRAP> | + | <wrap info>All audio inputs are bipolar and support OverVoltage. A good hard clipping.</wrap>\\ |
| - | <WRAP center round info 60%> | + | <wrap info>The SIG1 and SIG2 has inverted signal audio inputs.</wrap>\\ |
| - | CV inputs are in a 0 to 5V range.\\ | + | |
| - | </WRAP> | + | |
| - | <WRAP center round info 60%> | + | |
| - | All audio inputs are bipolar and support OverVoltage. A good hard clipping.\\ | + | |
| - | </WRAP> | + | |
| - | <WRAP center round info 60%> | + | |
| - | The SIG1 and SIG2 has inverted signal audio inputs. | + | |
| - | </WRAP> | + | |
| <WRAP clear></WRAP> | <WRAP clear></WRAP> | ||
| It seems all VCA cells invert the signal, then same thing for the VCA part.\\ | It seems all VCA cells invert the signal, then same thing for the VCA part.\\ | ||
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| </WRAP> | </WRAP> | ||
| </WRAP> | </WRAP> | ||
| - | <WRAP center round info 60%> | + | <wrap info>LOG CV Input for cut-off Frequency is inverted input.</wrap>\\ |
| - | LOG CV Input for cut-off Frequency is inverted input.\\ | + | |
| - | </WRAP> | + | |
| Lowest frequency is at 5V, Highest at 0V.\\ | Lowest frequency is at 5V, Highest at 0V.\\ | ||
| This CV needs to be inverted too.\\ | This CV needs to be inverted too.\\ | ||
| \\ | \\ | ||
| \\ | \\ | ||
| - | <WRAP center round info 60%> | + | <wrap info>LOG CV Input of the VCA seems unusable.</wrap>\\ |
| - | LOG CV Input of the VCA seems unusable.\\ | + | |
| - | </WRAP> | + | |
| I've got only some NJM2069**BD** for spare then I used the **D** version present in my EX-800 to test Log CV of the VCA in the 2 versions, and it appears to be definitively not usable for both!\\ | I've got only some NJM2069**BD** for spare then I used the **D** version present in my EX-800 to test Log CV of the VCA in the 2 versions, and it appears to be definitively not usable for both!\\ | ||
| Maybe some other version (AD, DA...) of the chip release this function. I don't know.\\ | Maybe some other version (AD, DA...) of the chip release this function. I don't know.\\ | ||
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| ==== Choices made during prototyping ==== | ==== Choices made during prototyping ==== | ||
| - | - SPDT function added to the VCF outputs to switch between -12dB and -24dB... Of course.\\ | + | - **2P/4P Switch**, SPDT function added to the VCF outputs to switch between -12dB and -24dB... Of course.\\ |
| \\ | \\ | ||
| - | - SPDT for ByPass function... Of course too!.\\ | + | - SPDT for **ByPass Switch**... Of course too!.\\ |
| \\ | \\ | ||
| - | - Polarized caps to all audio inputs of the module, SIG1, SIG2, EXT(named like that to be clear) and 1 polarized cap on the output.\\ | + | - **DC Offset**, Polarized caps to all audio inputs of the module, SIG1, SIG2, EXT(named like that to be clear) and 1 polarized cap on the output.\\ |
| I checked, with some low offset Op Amps like NE5532 or NJM4580, this is enough to maintain offset and stability in all the circuit. Then no need of big and expensive bipolar caps between stages in circuit.\\ | I checked, with some low offset Op Amps like NE5532 or NJM4580, this is enough to maintain offset and stability in all the circuit. Then no need of big and expensive bipolar caps between stages in circuit.\\ | ||
| - | - Remember, I want the switching between the configuration modes digitally controllable. (MIDI, Recall...You know why ;) I try all the valid configurations, and finally choose the 4 most interesting.\\ | + | - **Config Modes**, remember, I want the switching between the configuration modes digitally controllable. (MIDI, Recall...You know why ;) I try all the valid configurations, and finally choose the 4 most interesting.\\ |
| <WRAP group> | <WRAP group> | ||
| Line 196: | Line 184: | ||
| * 1 logic line for 2P/4P switching, 4P at Low, 2P at High. | * 1 logic line for 2P/4P switching, 4P at Low, 2P at High. | ||
| * 2 logic lines to code the 4 Configuration Modes. | * 2 logic lines to code the 4 Configuration Modes. | ||
| - | <WRAP tip>Obviously you're not obliged to use this switching circuit. All I/O are individually accessible on pin header.\\ | + | <wrap tip>Obviously you're not obliged to use this switching circuit. All I/O are individually accessible on pin header.\\ |
| You can use it to access I/O or to set it in the static configuration of your choice. | You can use it to access I/O or to set it in the static configuration of your choice. | ||
| - | </WRAP> | + | </wrap> |
| - | + | ||
| - | To be continued... | + | |
| + | - About the **CV inputs** of the chip: | ||
| + | I chose to use some 0 to 5V RRIO OpAmp, for precision, voltage limiting and as DAC/CV Summing(Inverter) function. | ||
mb_2069.1505902566.txt.gz · Last modified: 2017/09/20 10:16 by antichambre
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