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Shuriken

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Posts posted by Shuriken

  1. Hi,

     

    I use an external ground fault circuit interrupter but I think it's impossible that the case gets conductive. (: But you are absolutely right, if you don't exactly know what you are doing and don't trust what you have done you should better buy your psu. The picture is not a recommendation how to construct the psu. The picture is now adjusted.

     

    If you only get 0,5 Ohms between the DC-plug (source) in the case and VCC (target)  you will loss 1V (current 2A).

    I think the wire-diameter is the first part you should consider.

     

    I am pretty sure the case is already conductive since it's metal  :rolleyes: Connecting earth to the case is something which is a nobrainer, same goes for the fuse on the mains part. But it's just our advice to keep you and your loved ones safe, as always you are welcome to ignore our advise.

     

    For the cable loss part they invented the sense mechanism, which is on a lot of switching psu these days. The psu will compensate for any cable losses. And there is no part in the MB6582 which will need 2A.

  2. I had been looking on this schematic, the extra holes are probably from a later revision. So i did not notice.

     

    No, I looked up the email from way back, here's the bit about the Optrex:

    https://dl.dropboxusercontent.com/u/3429552/Screenshot%202014-08-19%2022.15.53.png

     

    Could the second wire I added be the cause of my problems? I'm going to remove it anyway, but it's just the grounds, right?

     

    No, it's not ground. It could very well be you killed T1 with the extra wire.But since i don't have the schematic of the new revision i am not sure. But since T1 is responsible for the current flow to the backlight, it's a likely suspect.

     

    I would remove the extra wire and my guess is you need to replace T1 (BC337). But you could check first.

  3. I have 3 1HE(U) Cabinets here. 2 are still new in original box, one i have opened. I bought these at Pollin for 22,65 euro. Quality is not great, but so is the price.

     

    I want to sell these for 15 Euro the piece. Ask for postage costs to the country in question.

     

     

  4. I cannot take credit for the table. It's an article on a dutch website (circuitsonline.net) The pcb is also there.

     

    Yes the transformer voltage is in AC (haven't yet seen DC transformer :wink:)

     

    C4 needs to be applied in powersupply box.

     

     

    As for the LM2596, you could experiment with faster diodes (MUR120) to rectify. And a big capacitor in front of it.

  5. Unfortunately it is not that easy. It all depends on what regulator you use and so on. For the 78xx regulator the following table applies:
     
     

    Output-voltage	Outputcurrent	Transformervoltage
    V	100 mA	1 A	2 A	V
    2	78L02	-	-	5
    3,3	78L33	7833	-	9
    5	78L05	7805	78S05	9
    6	78L06	7806	-	9
    7,5	-	-	78S75	9
    9	78L09	7809	78S09	12
    10	78L10	-	78S10	12
    12	78L12	7812	78S12	12
    15	78L15	7815	78S15	15
    18	78L18	7818	78S18	18
    24	-	7824	78S24	21 of 24

     



    000030.GIF
     
     
    The parts need to be adapted to current and voltage. With a low voltage (below 5 V) C1 can be decreased to 1000 µF. With voltages above 15 V en 1 A, C1 needs to be 4700 µF. With currents above 1 A moeten the diodes need to be replaced by 1N5401's.
    C4 needs to be applied if the wiring between powersupply and appliance exceeds ±15cm
     
    Partlist:

    • C1 = 2200 µF/35 V (see text for remark)
    • C2, C3 = 100 nF
    • C4 = 10 µF/35 V (see text for remark)
    • Br1 = 4x 1N4002 of 1N5401 (see text for remark)
    • Vr1 = 78xx
    • T1 = trafo
  6. OK, I'll try it. Hovever shouldn't it sound good even without 7805?
    In theory yes, but it depends alot on the components in front of the circuit. Did you provide power with a transformer?

    Hawkeye, I just looked at your calculations again

     

     

    and wondered, why 9V AC input for MB-6582 in PSU Option A is considered OK even with plain 7809 (non-LDO) ?

    I make an assumption that it worked in your case because your transformed was good enough (25VA) to sustain 9V AC under load.

    a 7809 can never pull more load then 1A, so highly unlikely. It's probably more todo with the amount of AC coming out of the wall socket. If the transformer outputs 9VAC at 230V and you only have 225V or less coming out of the wall....
  7. Hi Benoit. STM32 Cortex M4 good choice and more safe regarding the shortness SRAM on your RTPMIDI OEM board  :rolleyes:

    Like the hardware, the code will be open :question:

    I don't think Benoit is using an STM32 M4 for the RTPMIDI board. However the MIOS32 part is running on that MCU. And yes the code for that is open :wink:

  8. I guess it's this book:

     

     DSP_1.jpg

     

    Most impressive :thumbsup: . Unfortunately not yet translated by Elektor to any other language. I can read basic french, but this probably has to much topic specific words for me.

  9. The KORG nanokontroll probably has drivers which take care of this.

     

    CoreMIDI and ALSA sound like names from the build in drivers from the OS. So not sure how you would fix this. Maybe with some kexts and kernel driver hacking. But that seems like a lot of trouble to me.

  10. The 78xx regulator needs an additional 3V to properly regulate.  If 12V DC output is required you need to input atleast 15V DC.

     

    So for the old 6581 SID, 12V AC is just barely enough. But only if in your house the AC is properly 230V. So it's safer to choose 15V AC.

     

    For the 8580 or 6582 (new) 9V AC is again barely enough to get the additional 3V. So it's better to opt for the 12V AC. I would advise against using the 15V AC as all the excessive voltage will be dispensated as heat.

     

     

    If i can make a suggestion, if you don't want to go for a big fancy SMPS. Then maybe you can look for an LM2596 solution. A lot of companies are selling these as ready made modules. Usually for a couple of euros. These small boards are adjustable, high efficient and have a switching frequency of 150 kHz.

  11. Well i got a bit carried away looking for hardware options. But i think it should be doable to make a good and usable hardware design.

     

    But the big problem is the software side of things. So maybe it's better to focus on that first? I am sure if there is a good use case, interest will come.

  12. I checked out the EZKit. But the price is quite steep  :pinch:

     

    And there is some major restrictions to the use of VDSP with EZKit, it will only work for 90 days. And only allows usage of 10922 words of memory for code space.

     

    And i knew about the Plugiator module :wink: The controls seemed quite limited to me. Something you could do much better with something like MB NG.

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