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mb_2069 [2017/09/15 18:35]
antichambre [The IC NJM2069]
mb_2069 [2017/11/08 12:10] (current)
antichambre [Choices made during prototyping]
Line 55: Line 55:
 === I used Poly-800 Service Manual page 6: === === I used Poly-800 Service Manual page 6: ===
 {{:​antichambre:​poly800_p6.jpg?​600|}}\\ {{:​antichambre:​poly800_p6.jpg?​600|}}\\
-In the Poly and EX-800 the 2069 is in **PRE** configuration. \\ +In the Poly and EX-800 the 2069 is in <wrap hi>**PRE**</​wrap> ​configuration. \\ 
-It means the **VCA** is **before** the **VCF**. The VCF has 3 Voltage controlled inputs, SIG1, SIG2 and VCF In. \\+It means the <wrap hi>VCA is before the VCF</​wrap>​. The VCF has 3 Voltage controlled inputs, SIG1, SIG2 and VCF In. \\
 Two VCO on SIG1 and SIG2 and a noise circuit is applied to the VCA In. \\ Two VCO on SIG1 and SIG2 and a noise circuit is applied to the VCA In. \\
 The VCF 4 Poles output is the Output of the filter stage. \\ The VCF 4 Poles output is the Output of the filter stage. \\
Line 63: Line 63:
 === The DW-8000 Service Manual page 22: === === The DW-8000 Service Manual page 22: ===
 {{:​antichambre:​dw-8000_p22.jpg?​600|}}\\ {{:​antichambre:​dw-8000_p22.jpg?​600|}}\\
-The DW-8000 is in **POST** config.\\ +The DW-8000 is in <wrap hi>**POST**</​wrap> ​config.\\ 
-The **VCA** is **after** the **VCF** Two VCO come to SIG1 and SIG2.\\+The<wrap hi> ​VCA is after the VCF</​wrap> ​Two VCO come to SIG1 and SIG2.\\
 The Noise Circuit is directly applied to VCF In.\\ The Noise Circuit is directly applied to VCF In.\\
 The VCA Input connected to the VCF 4 poles output.\\ The VCA Input connected to the VCF 4 poles output.\\
Line 72: Line 72:
 === The DSS-1 Service Manual page 18: === === The DSS-1 Service Manual page 18: ===
 {{:​antichambre:​dss-1_p18.jpg?​600|}}\\ {{:​antichambre:​dss-1_p18.jpg?​600|}}\\
-The DSS-1 is in **POST** config too.\\+The DSS-1 is in <wrap hi>**POST**</​wrap> ​config too.\\
 The only difference is the 2 switching Op Amp added between the VCF Ouputs 2P/4P and the VCA In.\\ The only difference is the 2 switching Op Amp added between the VCF Ouputs 2P/4P and the VCA In.\\
 {{ ::​post_2p4p_config.jpg?​600 |}}\\ {{ ::​post_2p4p_config.jpg?​600 |}}\\
Line 87: Line 87:
 {{:​antichambre:​2069_proto2.jpg?​600|}}\\ {{:​antichambre:​2069_proto2.jpg?​600|}}\\
 {{:​antichambre:​2069_proto1.jpg?​600|}}\\ {{:​antichambre:​2069_proto1.jpg?​600|}}\\
- +\\ 
-==== Precious information found once prototyped ==== +\\ 
-<WRAP center round info 60%+==== Precious information found about the 2069 once prototyped ==== 
-The SIG1 and SIG2 audio inputs ​are inverted. +<wrap info>The Absolute Rating Voltage is +/-5V, tried and fried ;​)</​wrap>​\\ 
-</WRAP>+<wrap info>CV inputs are in a 0 to 5V range.</​wrap>​\\ 
 +<wrap info>All audio inputs are bipolar and support OverVoltage. A good hard clipping.</​wrap>​\\ 
 +<wrap info>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.\\
Line 107: Line 109:
 </​WRAP>​ </​WRAP>​
 </​WRAP>​ </​WRAP>​
 +<wrap info>LOG CV Input for cut-off Frequency is inverted input.</​wrap>​\\
 +Lowest frequency is at 5V, Highest at 0V.\\
 +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.\\
Line 120: Line 123:
  
 ==== 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 half column>
 +{{ :​antichambre:​pre_mode2.jpg?​400|}}\\
 +Mode 0 - <wrap hi>​PRE</​wrap>,​ VCA before VCF
 +</​WRAP>​
  
 +<WRAP half column>
 +{{ :​antichambre:​post_mode.jpg?​400|}}\\
 +Mode 3 - <wrap hi>​POST</​wrap>,​ VCA after VCF
 +</​WRAP>​
 +</​WRAP>​
  
 +<WRAP group>
 +<WRAP half column>
 +{{ :​antichambre:​par_config.jpg?​320 |}}
 +Mode 1 - <wrap hi>​PAR</​wrap>,​ VCA Parallel VCF\\
 +They share same Input and Output.
 +</​WRAP>​
 +
 +<WRAP half column>
 +{{:​antichambre:​sum_mode.jpg?​320|}}\\
 +Mode 2 - <wrap hi>​SUM</​wrap>,​ VCA + VCF, \\
 +They share only output.\\
 +VCF direct input is tied to ground.
 +</​WRAP>​
 +</​WRAP>​
 +\\
 +For this purpose I use 3x DG413 Analog Switch on the breadboard.\\
 +I reduced it to 1x DG333 and 1x DG413 on PCB.\\
 +All Audio purpose active components like OpAmps and Analog Switches are connected to +/-12V. We wants 2069 distortion only!\\
 +The 2069 is supplied by +/-5V, then it will be the first to saturate.\\
 +\\
 +This is the block diagram of the switching circuit
 +{{ :​antichambre:​block_mode.jpg |}}\\
 +Here the circuit is in default state.\\
 +The 2P/4P switch has its own line control.\\
 +The two Bypass SPST form a SPDT Switch and have their own control line too.\\
 +All others 5 switches are for Mode purpose.\\
 +5 is too much lines, remember I've got only 4 modes then I may reduce it to 2bits, 2 coding lines.\\
  
 +I inserted the Switches in the circuit to get this truth table:\\
 +{{ :​antichambre:​truthtable.jpg?​200 |}}\\
 +As you can see E=B and D=C then it's reduced to 3 lines.\\
 +Now I add my 2 required inputs lines, ModeA and ModeB\\
 +We can extract that:\\
 +{{ :​antichambre:​truthtable_reduced2.jpg?​400 |}}
 +It's ok, I need 1x OR gate and 1x AND gate, on PCB I use 2 small 74HC1G32 and 74HC1G08.
  
 +And finally I obtain to <wrap hi>​control everything with 4 lines</​wrap>:​\\
 +  * 1 logic line for Bypassing, Active at High.
 +  * 1 logic line for 2P/4P switching, 4P at Low, 2P at High.
 +  * 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.\\
 +You can use it to access I/O or to set it in the static configuration of your choice.
 +</​wrap>​
  
 +- 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_2069.1505500528.txt.gz · Last modified: 2017/09/15 18:35 by antichambre