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Question: Will a standard 12v / 1,5A PSU work? Or is it too high voltage?

xoxerxoxer
edited September 2013 in General
Hi,

as mentioned I got my machine working :)
At the moment I'm using a huge universal PSU which works fine. I have a lot of PSU's from my external HDD's lying around. The ratings are all 12V and somthing between 800mA and 1,5A.
The Question is can the internal LXR voltage regulator handle the 12V? I won't buy a new  9V one if it is not necessary.

Thanks you.

Comments

  • fcd72fcd72
    Shure 12V will work, the 7805 regulator can take up to 16, 17V but be aware it converts the excess Power to Heat.

    I suggest you get a approx 300mA 7,5V Switching Power Adaptor, the 7805 Regulators need about 2V headspace to work properly, so theres only 2,5V that will be dissipated into heat instead of 7V from your PSU.

    This is the one i pretty much use for everything (Shruthi, Anushri, LXR, MidiALF... you name it, it powers it.)
  • PatrickPatrick
    edited September 2013
    yes ,7805  needs 2V drop voltage
  • julianjulian
    I would not recommend anything above 9V (7.5V prefered) to power the unit.
    Or you may need a bigger heatsink.

    With a 12V PSU you don't want to touch the 7805 anymore (which is the point where I say it gets too hot)
    It will work anyways. If it gets too hot the 7805 should shut down.
    But all the heat is generating uneccessary stress for the components around it.
    The electrolytic caps right next to the regulator will get hot, too.

    So I say get a propper 7.5V supply. Until it arrives you should be finde running from 12V for a while, as long as you don't let the unit run for hours or in a well heated room ;)
  • xoxerxoxer
    Ok thank you. I will order the suggested one :)
  • bassFantbassFant
    edited September 2013
    Is 300mA at 7,5V sufficient for the LXR? I didn't meassure it so far but the instructions said at least 600mA at 7V and my LXR-Kit from the first batch doesn't work properly with two different power supplies wich are rated 500mA at 7,5V while no problems when using a 800mA wallwart.
  • fcd72fcd72
    edited September 2013
    The suggested one outputs 600mA and is proven to power 1 LXR or 3 Shruthis or 2 Shruthi + Anushri or MidiALF, Shuthi, Anushri. And thats because i only soldered 3 jacks to it ;-)

    BTW, i use the bigger 1200mA Version to Power Microwave XT, MicroQ and RackAttack as the originla Waldorf PSUs are linear ones and brick the size of a 40" Container. I have about 20 of these Wallwarts and no problems whatsoever so far, they are even DIY BenchPower Supply testes and 100% short protected.
  • bassFantbassFant
    @fcd72: In your first answer you suggested 300mA and the link to Reichelt refers to a power supply which is specified as 300mA also. ;)
  • nightworxxnightworxx
    edited September 2013
    What Frank is trying to say is that you are now caught in the rabbithole of DIY. So this means you will end up with a bunch of wallwarts of minimalistic size or with one well sized with a multiple plug, which can power all. Your choice. But the end is *ahem* well-known here.
  • fcd72fcd72
    the end is multiple wall warts of all sizes....
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