Ambika assembly instructions / BOM
  • No, this won’t line up. Boards are 1.6mm thick and there is no obvious solution to the problem – and it’s even more complicated if you take into account that a mobo might have unpopulated slots. The voicecards are not attached to the bottom of the case, they are just hanging from it.

  • great news, fcd72!
    thanks that you do the hardware ordering for us.

  • There is no 3rd spacer for the Voicecards, just a nut to secure it. Calculate yourself that 12mm + 1,5mm + 12mm + 1,5mm + 10mm != 40mm and even the 12mm supposed won’t fit. The Voicecards hang like Stalactites from the MOBO, hence the 40mm spacers between them.

  • Okay it’s clear now :) I was getting confused by the first pic here – presume those bottom spacers are acting as nuts.

  • The unit you see on the photos is a prototype.

  • @fcd72
    Good to know you are providing ALL the hardware parts ;) +1 for the transparent part
    This time i will give you an adress in France I have quick sending with this adress
    no need to wait for banana grow up ;)
    BTW i have some trouble with the assembly of my wasp i will open a thread
    I don’t want to derailed this one with fruit of reunion island…

  • @fcd72: Thanks for that! Will save a fair bit of effort!!

  • Anyone know if it would be possible to socket the Ambika display?
    I’ve ordered an Optrex neg. green LCD, but I think I’m going to get the Futaba VFD, too. It would be a shame to wreck one or both, or the board, desoldering though.


  • i thought about socketing the display too and maybe found a way:

    -On the motherboard, you solder the 2X8 male connector.

    -On the back of the display, you solder the 12 wires (other are not used, protocol is only 4bits as shown the schematic PDF) or if any doubt, solder all the wires.
    But solder this way: the wires should be soldered around the hole, not inside.
    So mecanically, you can insert the display on the connector and solder each wire on the connector. This way, you can just desolder the wires to change display and don’t make any desoldering (and heat) on MOBO or display board.

    1230 x 1260 - 99K
  • Looks like it will work. But I think one needs to be careful not to make the connector protrude too much below the display, there is only 12mm between the motherboard and the voice card.

  • Less than 12mm as the wires stick a bit thru the voicecard. For security reasons you should calculate with 10mm.

  • Would these work?

    I’d envisage soldering DIL pin headers to the display so the pins stick out of the front of the display base PCB, with the plastic part of the header on the back. That way, the display could be plugged into the socket with no extra spacing. You’d have to cut the protruding header pins off on the back of the display.


  • Having said that, this solution would make it relatively easy to change the Ambika LCD, but wouldn’t make any rejected display any easier to use for something else. You’d probably still have to desolder the headers.


  • How about soldering solid core wire through each hole, but separate the two layers by enough room to get snippers in? That way you can cut the wires between the layers and just desolder individual bits of wire.

  • @mangros that might work. You’d have to desolder the wires from both mainboard and display though, which is what I was hoping to avoid.


  • I’d rather desolder lots of individual wires from both boards than try to desolder one header :)

  • @mangros if you remove the plastic part of a header with some fine wire snippers, you can desolder each pin individually.


  • You could also mount the Display, stick in a Pin of a header and just solder a tiny drop both on top of the Display + on Bottom of the MOBO for easier desoldering. Easiest would be just building a 2nd Ambika if you are not satisfied with your Display ;-)

  • @fcd72 Frank, did you get my email? Sent it to your account.

  • @xtrmnt
    Nope? When did you send this regarding what?

  • @fcd72 which email do you prefer, just replied to your email.

  • easy: solder a row of male header on the board. then take the plastic away.

  • Hello all,

    very nice project , i am very interested. Looks like a new modern Xpander !
    Anyway will it fit inside a standard eurorack 3he ? like this one ?

    What are the dimension of the full 3 layer boards ?

  • I don’t know how much the 40 char displays cost, but with the cost of even the 16 char OLED it makes much more sense to solder the header and use the connector. The display can be considered disposable when compared to the Shruthi or Ambika boards that can be damaged during removal. That’s the way I think about it anyway…

  • @dukino
    The MoBo PCB wont fit behind your 3HE Front Panel directly but you could Panel Mount the Pots, Buttons + Display.

  • Got home after a week on the road for work and found the Mouser & Digikey boxes came, loaded with Ambika parts! Now, the wait…............

    FYI, this is the LCD I got. Didn’t look too closely at the pic, but the display is surrounded in white plastic. Dunno how it will look until I get the MoBo. But, keep that in mind if you are looking for an LCD. May have to get some flat black paint. :(

    EDIT: Crap! I don’t think this will fit! to the right the case around the LCD sticks out between the mounting holes. Looking at the pics in the “build it” page, it looks like the MoBo does not have a notch for this. Pichenettes, is that a Proto board? Will the Pioneer Boards have a notch cut out on the right? Harumph. I’d hate to take a dremmel to it. Oh well.

  • yes they will. for us Optrex aficionados.

  • > yay rosch! Gooooood nooooos!

  • @qp: the picture of the PC board at the very top of the build page is the latest revision and shows the cutout.

  • @qp I’ve ordered the green neg version of that same display. Didn’t realise it had white plastic around it (assuming this one does too). Then again, I’ve only ever seen tiny photos of it, and you can’t really see very much. I’m interested to see what the white one looks like in action.

    I’ve also bought a Futaba VFD from RS. Have to work out some way to socket them do I can try them both without desoldering.


  • @toneburst-I reckon putting the 3M sockets on the displays, soldering the pin header to the mainboard and using a double bolt spacer to the mainboard (ie 4mm) will do the trick….

  • @fcd72
    Tnx u ! ok it doesnt fit a 3HE natively but will it fit a 4HE ?
    May i still have the full dimension in cm of the all thing ?
    A mechanical drawing with dimension would be gold !
    It is essential to me that it can be rack mounted

  • The actual Case is 170mm deep/high. I wouldn’t recommend mounting the Stack as it is done in the Standard Case – its rugged but not “MilSpec RoadProof”. I doubt the Stack of the Boards would survive the typical “I don’t care a shit for the Equipment” handling of a Roadie tossing your Rack down the stairs instead of waiting for the elevator when just mounted Tilted 90° to a Frontpanel of a RackUnit. You then better mount the Stack with the Voicecards first to the Bottom (or an auxilarie Frame) so the Mobo + the Voicecards Stack are secured. This means you would have to move the Controls + Display to the Front (panel Mounted is mechanically better…). Maybe you can wait till i have my personal Version of this done??

  • tnx again
    i understand what u say but my unit will always be home in the studio no gig no travels
    Yes i agree is easier to lock everything on a solid base and move the rest
    but is not trivial to rack mount a loose lcd ! Sure i can wait for your version !
    Cant wait to see it in fact … Anyway Am i the only one that wants/needs a 19” rack version ?

  • Nope, I’m going to do a 19” Unit for my Studio, more or less the same height (5u?) as a MicroWave XT or MS200BR – with some extras ;-)

    Mounting a LCD is quite simple – the have 4 2,5 holes and you can easily glue a M2,5 Spacer to the FrontPanel…..

  • if you do what fcd72 describes you can get away with 2 HE.

  • Just measures: 2HE would prevent you from using some nice Buttons and keep the Pots really dense to the LCD – 3 HE would be possible. I had a look an my approach would need 6 HE, but it would be more like a Ambika XT besides being not orange

  • Ambika XT…..... i probably better make a temporary case again (here we go again)

  • Yo Rosch – just take a standard Case (ill convince Olivier to sign each case on the bottom thats ordered for the Pioneers Run from him ;-) ) and then build a 2nd one. It may take some time to make it right, it should compare the the Shruhti Programmer/XT like the Ambika to the Shruthi – loads of work to keep track with Oliviers superb Work!

  • yes i figured that it would go the same route again, ambikamania

  • So… I’m currently filling the cart on mouser for the ambika.
    One of the few things backordered are the 6P header STRs. Actually, one easy replacement is those

    They seem to fit, you just have to cut them in half :)

  • I’ve found it cheaper in the past to buy male pin header in bundles of long strips from eBay, and cut or snap to size.


  • @MicMicman: Try this Mouser item from Harwin: 855-M20-9990645 It’s cheaper than the FCI part too :)

  • good catch. But actually, getting the 12 pins and slicing them in 2 is slightly cheaper :D

    By the way, I don’t really understand what they’re standing for. They were in the saved projects linked on page 2 (that include several mistakes in part-counts by the way, I’ll link the correct ones later), but they don’t match the part list, that expects 3 pins (and not 6 pins) headers (for the jumpers). I think one of them even includes the 3 pins headers. Not a big deal at all, though.

  • @pichenettes how much space is there between the top of the Ambika main board and the bottom of the enclosure top-panel? Just got my Futaba VFD from RS, and there are some components sticking out of the bottom, so it’s effectively substantially deeper than the Optrex LCD that also arrived today. I’m thinking it might need to be installed above the board, rather than below, if there’s room.


  • @toneburst
    you can easily use 12mm spacers to the top if that helps. if you plan to get a plexi case ill gladly add the 2mm for you as i also want a VFD :)

  • Sorry, I hope this time it’s my last question about the ambika BOM...

    Would those heatsinks fit for the 8v regulators?

    To me they look pretty similar to those you mentioned on farnell, but maybe i’m missing something…

  • I’m starting to think the Futaba VFD might be a no-go. It has a couple of capacitors on the back that protrude about 5 or 6mm below the base of the PCB. It appears to be too ‘deep’ to go on top of the board.


  • Hey a|x,

    we will make it somehow fit – my own interest ;-) BTW, i got your eMail but I’m fuckin busy right now so i ignore all incoming mails – don’t give “
    the THING away!!

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