ssm2164_getting_started
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ssm2164_getting_started [2018/04/23 13:22] phatline [Resistor Solution low voltage - seppomans prefered] |
ssm2164_getting_started [2018/04/26 19:28] (current) phatline |
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| - | ======= ssm2164_seppoman pcb - getting started - how to setup ======= | + | ======= ssm2164_seppoman pcb introduction ======= |
| + | seppomans building information;[[ssm2164_pcb]]\\ | ||
| the following informations are take from the midibox forum, its a collection of infos, without the claim to be 100% true, i will try to test the given information. | the following informations are take from the midibox forum, its a collection of infos, without the claim to be 100% true, i will try to test the given information. | ||
| + | |||
| + | ====== Shematic ====== | ||
| + | not found anywhere... m( \\ | ||
| + | also reverse engeniering/understanding/troubleshooting/moding is nearly impossible when the pcbs are stuffed, because most of the traces are on the component site... or hidden behind the black paint\\\ | ||
| + | --- first i want to know for what are those POTs? Input Gain of Audio? or of CV? or some BIAS? seppoman said nothing...\\ | ||
| + | POT P1 middle & right Pin connected to VCC-\\ | ||
| + | POT P1 left Pin connected to a 27K Resistor and this resistor to a nother 27K Resistor which is connected to CV1+ Input. the middle point of this2xresistors is going to the TL74-OP-Amp Pin1 which is a inverting input...\\ | ||
| + | The Output of this TL74 Stage is Pin1: its connected to Pin 6 SSM2164, which is the CV-Input\\ | ||
| + | When i measure Pin6 to Ground, and Turn P1 most left:1,8V... Turn P1 most right: 2,47V\\ | ||
| + | so what does it? no one said: its a zero offset for bipolar cv? or is it gain-control? FIXME m( \\ | ||
| + | |||
| ====== Power ====== | ====== Power ====== | ||
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| ==== Resistor Solution low voltage - seppomans prefered ==== | ==== Resistor Solution low voltage - seppomans prefered ==== | ||
| **R9...R16 > 5.6k** (only on the channels that are setup for bipolar mode)\\ | **R9...R16 > 5.6k** (only on the channels that are setup for bipolar mode)\\ | ||
| - | **+-3.5V to +-5.8V** Bi-Polar calibration range | + | **+-3.5V to +-5.8V** Bi-Polar calibration range\\ |
| **Pro:** easy job, still have a decent precision when calibrating.\\ | **Pro:** easy job, still have a decent precision when calibrating.\\ | ||
| - | ==== Resistor Solution Stock - NorthernLightX prefered ==== | + | **Con:** “just change the jumpers if you need some channel in bipolar mode” thought will not work. (FIXME really?) |
| + | ==== Resistor Solution Stock - -5V Level shifter - NorthernLightX prefered ==== | ||
| we came to the conclusion that it's probably much easier to have the AOUT only output **unipolar 0 to 10 volt**, and design **a simple -5v level shifter board** that can be used as an add-on (or separate module with hands-on access to the level shifting) to **shift the output to -5 to +5 volt** where needed.\\ | we came to the conclusion that it's probably much easier to have the AOUT only output **unipolar 0 to 10 volt**, and design **a simple -5v level shifter board** that can be used as an add-on (or separate module with hands-on access to the level shifting) to **shift the output to -5 to +5 volt** where needed.\\ | ||
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| **R9...R16 >2.2k** (on all channels). (QUESTION WHY ON ALL? FIXME)\\ | **R9...R16 >2.2k** (on all channels). (QUESTION WHY ON ALL? FIXME)\\ | ||
| **+9.5V to +22V** Uni-Polar calibration-range\\ | **+9.5V to +22V** Uni-Polar calibration-range\\ | ||
| - | **+-2.4V to +-5.5V** Bi-Polar calibration-range\\ | + | **+-2.4V to +-5.5V** Bi-Polar calibration-range ( dont think so FIXME)\\ |
| **Pro:** preserve the "just change the jumpers if you need some channel in bipolar mode" thought behind this option.\\ | **Pro:** preserve the "just change the jumpers if you need some channel in bipolar mode" thought behind this option.\\ | ||
| **Con:**dramatically increase the calibration range, i.e. exactly calibrating the outputs will get harder because the same angle of turning the pot will have much more impact.\\ | **Con:**dramatically increase the calibration range, i.e. exactly calibrating the outputs will get harder because the same angle of turning the pot will have much more impact.\\ | ||
| + | |||
| + | |||
| + | ====== MODs ====== | ||
| + | ===== MODE Resistor - Noise vs Distortion ===== | ||
| + | SSM2164 Pin 1 (the first pin) sets the "Mode" | ||
| + | ==== Class AB ==== | ||
| + | Pin 1 is Open, no Resistor to +12V (PCB Default)\\ | ||
| + | Lower current results in higher distortion/lower noise.\\ | ||
| + | ---i do want distortion and dont care about noise--- so i do not change anything, the pcb is fine. | ||
| + | ==== Class A ==== | ||
| + | Pin 1 is Connected to +12V via a Resistor\\ | ||
| + | Higher current results in lower distortion/higher noise\\ | ||
| + | lets look in the datasheet:\\ | ||
| + | {{:phatline:ssm2164-ab-a.png?600|}}\\ | ||
| + | Figures 11 and 12 show the THD and noise performance of the | ||
| + | SSM2164 as the bias current is adjusted\\ | ||
| + | |||
| + | I_MODE = ( (V+)−0.6V )/ RB\\ | ||
| + | 1,52mA = (12V-0.6V) / 7,5K\\ | ||
| + | Leaving the MODE pin open sets the SSM2164 in Class AB with 30 μA in the Gain-Core\\ | ||
ssm2164_getting_started.1524489774.txt.gz · Last modified: 2018/04/23 13:22 by phatline
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