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Portable LXR - headphone amp and battery power

borfoborfo
edited October 2013 in General
I've just made my LXR portable...  It runs fine off 6 rechargeable NIMH AA batteries, and I built a cheap headphone amp (search ebay for "RA1 headphone amp kit" - I paid $17 shipping included, or you could just build one yourself), and stuck that to the bottom of my case under the LXR frontplate.  The amp has its own power, and two leads that I can plug into the LXR audio outs when I want to use the amp. 

Comments

  • aerroraerror
    nice! i was thinking of making mine portable too but i stuck with the headphone amp bom (i rather want to source the parts myself than buying a kit). how long does the lxr run on battery power and how much mah do the batteries you use have?
  • borfoborfo
    edited October 2013
    I haven't run it long enough to run the batteries out yet.  I think it'll run for a while though.  It's 6 x 2700mah batteries in series, so 2700mah @ 7.2 volts...  I haven't checked what the LXR draws, but another thread suggests maximum draw is about 600ma...  I figure I should be able to get a few hours out of the batteries.
  • aerroraerror
    please let us know when you've figured it out. thanks in advance.
  • effegeeeffegee
    A headphone amp would be nice, but for now I'm using a dual 1/4" plug-to-stereo jack to plug in headphones. It's a bit in the quiet side, but not too bad.
  • jnasterjnaster
    you a a schimo for the battery pack. and headphone amp
  • borfoborfo
    edited November 2013
    I removed the standoff in front of the mainboard, and now the battery pack sits perfectly under the right side of the front panel.  The headphone amp is on the left side with its own batteries.  I just plug in the AA battery pack and the headphone amp audio leads when I want to run it on batteries.

    Tonight I set up a pattern, and left it running.  The LXR's been running off of 6 2700mah AA batteries for four and a half hours now - it's still going strong.

    Edit: Six hours now, still going.  I'm going out for a bit...  We'll see if it's still running when I get back.
  • borfoborfo
    edited November 2013
    Anyone know if there would be anywhere I could pull +9v and -9v from the LXR?  The headphone amp needs both - right now it's powered by two 9v batteries, but it'd be nice to get rid of those and just pull power from the LXR if that's at all possible.

    Could I make that work?

  • tsvtsv
    I was thinking of a way to do this as well.

    If you tapped the 9v before the 5v regulator before D1 and then inverted it using something like this:

    http://www.madbeanpedals.com/projects/RoadRage/docs/RoadRage.pdf

    Then you could have a bipolar 9v supply to run the headphone amp. If the headphone amp was small enough to fit inside the LXR then you could just wire it all internally and add a headphone jack to the back.

    You'd need a 9v supply that could handle all this of course.




    Sent from my iPhone using [URL=http://tapatalk.com/m?id=1]Tapatalk[/URL]
  • loderbastloderbast
    have a look at the power supply part of a shruthi filter board.
    you could hack up something like tsv suggested, on a little bit of pearfboard. but simpler
    basically lt1054 and a bunch of caps. depending on your input voltage you don't even need regulators.

    not sure though if it is enough for the current, your headphone amp draw, but i think so - lt1054 gives 100ma max.

  • borfoborfo
    It was still running when I got home at 4am, died sometime before I woke up.  So, 6 2700mah batteries can run the LXR for over 8 hours.


    Cool, thanks for the power supply tips - I'll try that out.  This headphone amp is supposed to get 30-50 hours off two 9v batteries, so I imagine it draws less than 100ma.
  • aerroraerror
    8h is quite a long time. nice!
  • acidhouseforallacidhouseforall
    what do you think about this ? http://www.paia.com/proddetail.asp?prod=9605K

    It needs +/- 5/18 volts. Could it run from the LXR DC socket ?
  • acidhouseforallacidhouseforall
    or maybe mount this is the case... http://tangentsoft.net/audio/cmoy/misc/mini-cmoy-layout-0150.pdf
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