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K-rAd's MB SEQV4 Progress?

k-rAd MB6401

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Starting a post to show the progress of my MIDIbox seqv4 build.




Ordered the STM32f4 CORE and MIDI IO.

They are in progress.


stuffed the 20 pin dip in backwards! oops! How the fuck did i do that? :(
Marked it to remind myself.
Also wating for the 25 position headers for the discovery socket. i had a hard time finding these in the US. so ebay? ok.
Also had to order the 74HCT541 on ebay.

Also ordered an AOUT original version which i don't have parts for yet.
I am waiting for the seqv4 control panel pcb to show up at smashTV.
Also need a second MIDI IO pcb from smashTV.
i may buy a panel from fabien at "thebeast".
i may order a panel from frontpanelexpress.
i am on the list for the 3rd round of the "SEQ4 Heidenreich Case Bulk 2014".
i need to design and build a power supply.
i want to control my modular eurorack and midi gear.


alsoneed to fixmyspace bar!
Edited by k-rAd MB6401
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  • 3 weeks later...
  • 4 weeks later...

Congratz to the CS board! I see you've got the power supply ready. Gonna follow your progress as I expect to receive mine board too.


Can I have a ribbon-cable-newbie question? How do you attach the cable to the connector? Is it just plug and push action or is there a special tool needed? On the connector pics elsewhere I saw little blades for each wire. Is there a specific ribbon wire distance that has to be appropriate for the connector? I've got some spare ribbon cables of various thickness but never used them with connectors so please bear with my dumb questions. I guess I'll find out when I receive the connectors but any hints or practical tips are welcome. Thanks.

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Making the connectors properly takes a bit of practice, but it's not too hard...  You might screw a couple up before you get it right, but once you figure out the technique, the IDC cables "just work".  When you apply pressure to crimp the cables, make sure the pressure is perpendicular to the connector, don't apply uneven pressure, or pressure at an angle.  If you have trouble with a connector you've made, test it with a multimeter to make sure all wires are connected, and no wires are shorted to their neighbour.


Make sure the two connectors are orientated properly before crimping them on to the ribbon cable - there are "pin 1" indicators on the connectors, make sure the Pin 1 indicators on both connectors are both attaching to the wire you've designated as Wire 1.  Take a minute to think about orientation before crimping, there are several different possible ways to attach the connectors to the cable, and only one of them is right.  There are also little protrusions on the connectors that fit in the connector shroud on the PCB, so you can only plug them in one way if you're using shrouds on your PCB...  The protrusions are marked on the PCBs...  Just take a minute to think about orientation before crimping the cables, and you'll figure it out - it's easy once you get it, but it's hard to explain in words. 




And make sure the cable is orientated properly when you plug them in (although for most of the connections on the MIDIbox SEQ other than maybe the LCDs, it's unlikely anything bad will happen if you get the orientation wrong, or if you've crimped your connectors on backwards, other than that the connected mudule won't work properly.)

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How do you attach the cable to the connector? Is it just plug and push action or is there a special tool needed?


There are special tools, but you don't need them.  I put the connector on my desk, lay the ribbon cable in it, put the top piece on, and then put something solid, heavy-ish and flat on top of it and push it down with your hand.  Just make sure the pressure is even across the connector and straight down.


You can crimp them in a vise too.  Some people use pliers.

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From what i can tell the connectors will accept 26 or 28 awg wire.

I'm using this stuff which i love. It splits nicely without ever tearing adjacent shielding.

It is 28 awg.



Also in my opinion there are two correct ways and two wrong ways to orient the wire. The wire may enter from either side of the connector without the pins getting mixed up. This way you can make the wire exit the connector in whichever direction suits the application.


I love the way you can see the light coming through the clear plastic between the conductors.

Edited by k-rAd MB6401
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  • 1 month later...

Ok so i have now populated the control panel. The seq is alive with one midi io module. It works it works!


I've left out the leds till a panel is in hand.

I need to stuff the other midi io, and i need to build the aout ng.


I have decided to put the analog outs on the sequeqncer case. So this means i dont believe that i need to have the line driver module. correct?

Patch cables from the aout module outputs should be able to be fairly long since they are after the TL074. Correct?


I realize i will need a +/-12v supply in the seq case. Also i would like the addition of extra clock and gate outputs as shown in the line driver configuration.

Can i simply add a dout module to the srio chain for this?


I'm not quite clear on how to connect the aout and another dout for more clocks and gates. Also what software changes will be required?




Edited by k-rAd MB6401
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  • 2 weeks later...

Alright analog outs are working!

output 8 wouldn't scale right :( 

all 7 other outputs are in tune and scale well.

So i turned 8 into a bipolar output and will use it for lfos and stuff like that.



no gates yet. Now i need a dout4x for the new gate srio config stuff. waiting for that in the mail.

i plan to have 8 trigger outs and 8 clock outs on my seqv4 case.


can i just hook up a resistor and an led on the gate outs so i can see them light up when triggered?

i guess there is only one way to find out...


the idea is to get the 8cv 8gate working plus 1 drum trigger and 1 clock output. then i can duplicate the other outs when im ready to build the case.

The test panel for analog outs.
Made from a PC case cover panel.



Edited by k-rAd MB6401
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