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latigid on

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Posts posted by latigid on

  2. midiphy Eurorack Expander Modules

    in MIDIbox SEQ

    Posted

    Thanks for the diagram! Just to preface, Eurorack is the Wild West of electronics. There are many ways you can put things together and some will give better results than others. The "fundamental flaw" in Eurorack is that the 0V line serves as both a reference and a current return path (i.e. an unbalanced system). If there are potential difference mismatches on the 0V lines, noise can result. So the idea is to have the 0V resistance as low as possible and to run power rails as much in a "star" configuration as possible.

    Searching a bit on MuffWiggler, the Row Power seems to have some history of noise problems. It might be that this is not the ideal way to power your Eurorack though there are a few things to try/clarify.

    • Is the mains connector to the DC brick 2 or 3 pins on the brick end? 
      • With the power off and any voltages discharged (take care!), what is the resistance from the earth pin to the DC barrel?
    • Your MG rack has two Row Powers, correct?
      • Are things actually connected like this on separate rows or more like the hand-drawn diagram?
    • What happens when you disconnect the ES-9 USB?
    • Is it a desktop or laptop computer?
      • If a laptop, what happens when it's running on battery?
    • What is the power distribution in the case? Flying buss or bussboard?
    • Is the Euroceiver powered with the case +5V or the onboard Vreg?
      • (I suppose the Vreg)
    • What happens if you power the Euroceiver with USB (check J5 jumper!) derived from the Mac while also powering the SEQ with USB?
      • Better might be to use a powered hub to increase the available current.
    • What happens if you power the SEQ from e.g. a phone USB charger rather than the Mac?
    • What happens if you remove the Euroceiver J0 jumper? 
      • Generally you do want to leave this connected, but disconnecting it will cut the 0V connection between the SEQ and Eurorack.

    Cheers,
    Andy

     

     

  3. midiphy Eurorack Expander Modules

    in MIDIbox SEQ

    Posted

    Hi Niels, 

    We heard of another similar issue. Could you explain exactly the wiring setup you use? It is important to know the power sources of everything (linear or switching PSUs, power banks, hubs), how they are plugged into the wall, whether you use a computer or laptop, the various jumper settings on the Euroceiver and so on.

    Is it particular modules or everywhere that you notice the hum?

    Best regards and Happy New Year!
    Andy

  4. understanding the .ngc code

    in MIDIbox NG

    Posted

    Nice to see your progress!

    It's confusing, but there is a difference between "bootloader hold" and flashing the "bootloader hex app" through MIOS Studio. 

    Bootloader hold, using the blue DISCO button, is when you mess up a custom app or the flash is corrupted somehow and the Core will not boot anymore. This allows you to fix the Core with a known good hex upload.

    Bootloader app is essentially the same but can be normally flashed with MIOS Studio. Upon USB re-enumeration you can then alter boot settings, including changing the LCD type.

  6. midiphy Eurorack Expander Modules

    in MIDIbox SEQ

    Posted

    What voltages do you read out of the output with 1/2/3/4/5 V... or min/mid/max?

    Looking at the MS-20 manual, it seems to expect a linear 0-8V CV for the VCOs? So maybe normal V/Oct scaling is already good? If you really need to work within the positive range, remove the offset resistor on any channels you would like to use in unipolar mode. These resistors xR34,xR35,xR36x... etc. are listed in the BOM on the transmute8 page.

  8. understanding the .ngc code

    in MIDIbox NG

    Posted · Edited by latigid on

    The circuit is a power-on reset (POR) that charges the cap for short period until the power rail stabilises. If you omit this then the displays will probably show garbage pixels. Only one POR is required for all of the displays. I would also suggest to wire a 1N4148  diode in parallel with the resistor with the cathode band at the +3.3V node.

  10. midiphy SEQ v4+

    in MIDIbox SEQ

    Posted

    2 hours ago, sis.tm said:

    Hi,
    on the ja board mine shows the gate of the track but i saw other movies showing track position and you say you can also show bpm. How exactly do you change the display of the ja board? 
    Cheers,
    Niels

    Hi Niels, it's there in the Utility -> Options menu. 

     

    Just now, Pivado said:

    Hi guys,

    I have been (silently) following Midibox for years and some time ago I made the decision to build the Midiphy SEQv4 myself. Everything went pretty well (great video instructions!) until the very end where I put it together into the box and the left display would not show anything during and after booting. When I press some keys random characters will show up on the display. I have now stripped down everything to a bare minimum (Core, usb/sd, 2 x display) and the problem still exists. I have tried swapping the display cables on the Core, if I do this the problem moves to the other display, this should rule out a problem with the display or the flatcable. I have attached a picture of what I see after booting.

    I hope there is someone here who could give me a hint on where I should start looking to solve the problem.

    Thanks,

    Pieter

     

    Midibox_problem.jpg

    Hi Pieter,

    You can try this thread for troubleshooting if you wish:

    http://midibox.org/forums/topic/20993-troubleshooting-midiphy-seq-v4/?page=1

    The OLEDs are probably fine but I would still suspect the cable. A slightly crooked crimp can short two lines together.

    Common issues with a display not working are:

    • J15_S not jumpered to 3.3V
    • R33D value (should be 560R)
    • Cable strands shorted together
    • Cable makes contact with components on the OLED PCB (isolate with kapton tape)
    • Cold joints or shorts on wCore 2x25 pin headers (trace back to pin names or even MCU pins according to http://ucapps.de/mbhp/mbhp_core_stm32f4.pdf)

     

    Best of luck!

    • Like 1

  14. midiphy SEQ v4+

    in MIDIbox SEQ

    Posted

    Hi Hal,

    Probably we/someone should write a wiki entry or something on the new features! The idea is something like this:

    • The encoders underneath the OLED displays work just as before
      • The encoder switch functions are in theory freely assignable but are typically used to accelerate encoder data
    • The first row of illuminated "Soft" keyswitches are equivalent to the GP buttons plus the dual-colour step LEDs of the Wilba version
    • The second "Selection Row" keyswitches change function depending on the button lit up around the datawheel on the JA board (see below)
      • These LEDs are also dual colour
    • The row of Apem/MEC switches should be familiar to V4 users
    • The RGB Beat LED flashes a different colour for the beat and the whole measure

     

    • The JA board has a built-in Activity Matrix and typically displays the track position in a single colour
      • Other display options like a custom logo or the current BPM can be displayed (both with optional beat flash; also for the TPD)
    • The datawheel functions as before and has a push function (currently not assigned to anything I think)
    • The JA board carries the transport controls (play, pause, stop etc.) and a few extras
    • The Selection Row buttons around the datawheel are:
      • Step View
      • Tracks
      • Parameter Layer
      • Trigger Layer
      • (Drum) Instrument
      • Track Mute
      • Bookmark
      • Song Phrase
    • On the JA board, press and release one of these to change the Selection Row function
      • Press and hold the JA button to temporarily change the Row function, which jumps back to the previous function on release
    • On the v4+, all 16 Selection Row buttons are accessible and multiple selections are possible by holding down several buttons simultaneously
      • Tracks are still colour-coded into groups of four tracks and named identically (e.g. G1T1-G4T4)
      • On the V4, tracks were chosen with four track groups and four tracks for a total of 16 tracks and only three trigger and parameter layers had dedicated buttons (normally holding Param./Trig. C would bring up the layers menu screen)

     

    • Rear panel has a USB B port (power/data) for better mechanical strength
      • Switch for USB OTG host is provided but we notice some devices are incompatible
    • Footswitch/gate input (currently not assigned to functions)
    • Rear panel LEDs:
      • Green: power
      • Orange: SD Card available
      • Red: any received MIDI IN
      • Blue: LED any transmitted MIDI OUT

    I think that's it!

    Best,
    Andy

     

    • Like 2

  17. Power Protection circuit for SID 8580

    in MIDIbox SID

    Posted

    Isn't the transistor topology similar to a linear voltage regulator anyway? 

    You might avoid the issue in the first place by starting with a more reliable power supply. Users here often also employ a crowbar circuit, so those might give you some possible ideas or directions.

    For your simulation, consider that the transistors should be properly specced to handle the current loads, also real components might have tolerances or voltage drops that push your limits.

  24. Troubleshooting midiphy SEQ v4+

    in MIDIbox SEQ

    Posted

    So all LEDs are lit except play? And it's a sudden change? 

    If the switches function properly, the issue is either with the anode side (IC3), THT resistors or with the LEDs themselves. 

    I would check individual diode functionality with a multimeter. A possible fault is that one or more LEDs are busted. 

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