julienvoirin

as seppo designed the filter and the vca from the aout-ng i think you don't need to change anything

i've tested the hotfix with 5.6k and it works stop me if i am wrong : we can't expand the offset (+/-2V) as it will be greater than the DAC max voltage (4.06V), isn't it ? what interest me is to still get (0 ; +10.67V) in unipolar and (-5V ; +5V) in bipolar

me -> :poke: <- seppo at least I know i worked well the best is certainly to only change R33/41

it consists to have diode (1n400x) at the output of the 78xx to avoid reverse voltage http://sdiy.de/de/projects/miniPSU.html basically the same idea

Dear boxers I am very happy to get different opinions on my problem So, i have 2 midiboxes with each an Aout NG : Seq V4 and MB CV The seq V4 has a power supply like this : -12V, Gnd, +12V, +5V. So the same GND. It is a commercial ELKA PSU for computers, but it isn't a switched PSU. 78xx share the same cooler, 7912 is on another. +/-12V supply J3:Aout and the GND is brought by the J19:core32 to J1:Aout NG Gnd and +5V supply J2:core32 (so directly without diodes bridge). But the bridge is soldered on the Core32 .. USB power option is not enabled. The MBCV has only one bipolar PSU : -12V, Gnd, +12V directly connected to the Aout NG J3 To supply the core, i connected wires between Gnd and +12V of the PSU to J1:Core Core and Aout are connected together by a ribbon cable between J7:Core and J1:AOUT. Normally, i've set the Gnd wire ; i will check tomorrow. in both case i don't have the full range in Aout bipolar mode : (-2.76 ; +2.76) When I measure the voltages between the PSU Gnd and all the different points were Gnd is supposed to be, i've always got 0.00V, on both midiboxes, core or Aout modules. +5V exists were expected, +/-12V too. I will put pictures tomorrow online (tonite i am at work :logik: )

no connect we both agree why measured values on AOUT PCB of R41 is 0,99k ? R33 1,1k ? I measured the same resistors from Reichelt bag (same colour code) and there are the expected values btw, thanks a lot for helping me to debug, really nice :flowers: i tested various things : changing GND reference (from the PSU, from the core), removing power supply leds (supply proof to check there is well -/+12v), testing without core, etc ... nothing change, except a bias as you mentioned earlier (and it is logical) without core i well measure -2V on R17/25 (DAC 0V, Min), but i can't know if there is +2V at max as the core is deconnected (Max value, DAC @ 4V) :getlost:

-1,06V to +1,06V As the Gain of TL074 is something like 2,5 (4,06V x G = 10,67) it is logical i got -2,76 ... +2,76V So now my question : how can I get a -2 +2 voltage on the P9 circuit ?? My supply is +/-12V Isn't there a problem of gnd and relative ground IYO (for the core) ?

-0,72 to -1,36V :sweat: a track to follow ?

seems there is no shorts i got this prblem on 2 aout ng pcb from smah tv. maybe there is defects into the pcb (!) as it could have been a bad batch i start to be disappointed as i wanted to use he ssm filters :ermm: could it be software related ? i recompiled it

it does ; from -2,75 to -1,51 while adjusting P9 min =0v middle = 2,03v max = 4,06v measured directly on the DAC and JP1 it is, but brown black black red. measured value = 9,96k really lost :geek: i am testing shorts now

thanks for your explanations seppo. it is what i thought so i use one single PSU (-11,96V, Gnd, +11,8V) to supply Core on J1 (with +11,8V and Gnd) and AoutNG on J3. Here are the voltages measured on free leg of the resistor Ri (black probe connected to Gnd of J4 on Aout), jumpers set on channel1 as bipolar (others channels not set) : Min (V/oct) : CV1 out = -2,78V R41 : -2,77V R33 : -1,43V R25 : -1,05V R17 : -1,05V Middle (V/oct): CV1 out = 0,00V R41 : -2,69 R33 : -1,34 R25 : 0,00 R17 : 0,00 Max (V/Oct) : CV1 out = +2,78V R41 : -2,60 R33 : -1,26 R25 : +1,05 R17 : +1,05 In unipolar i well have the range (0V ; +10,67V ) as expected I only connected together the PSU, the Core, a small control surface (just 74hc165 + 1 encoder + 2 buttons + C 100n) and the Aout NG modules. Gnd of core, psu and aout are connected together (tested with a multimeter)

download SVN for mios8 and compile the app using "make" command in the the seq v3 svn folder

dear boxers i've got a hard problem I've made the Aout-ng module of smash tv, in a midibox cv. I use a bipolar PSU -12V + 12v to supply aout ng on J3 (+12, gnd , -12v). i supply the core (completly stuffed) at J1 with gnd and +12V pin of the bipolar PSU. When in unipolar mode, i have the expected range (from zero to 10,67V). it's how i calibrated the gain before the opamp, using P1. Then i switched to bipolar mode, and set P9 (on channel CV1) to adjust the "middle" (in mb cv menu). I well have zero volt. BUT, when i set "min" and "max" i only have -2,76V and +2,76V. I should have -5V, +5V. I have this problem on all the channels. If i remove the gnd from Aoutng J3, and supply the core with a wallmart (9V DC) , i got a bias of +10V on my min and max voltages in bipolar ( min = 7V, middle= 10V, max = 12,56V ) ! The ground of Core is connected to the ground of AoutNG. So what's the problem ???

the cheapest in your case is to get a second hand midiman 8x8 (now midisport by m audio) i does midi patch and midi interface to computer

do you still have SSM2164 PCB for sale ? i need just 1 (or 2)

my panel is the same as the one in photo upward with a green stuff in background i give automatically some money to MSF every month. is it ok ?