SN Voice Help-Ribbon Cables

[MCDELTAT]

Hey there guys,
I'm new to the modular format and I'm having a hard time understanding a couple things. Been searching for documentation, but it's really hard to come by. I just purchased a SN Voice kit and my plan was to put it into a A-100 Mini Case, but I'm confused about the ribbon cable routing/configuration.

In the main 'SN Voice PCB' thread it was mentioned that you are supposed to use ye-old hookup wire and put it into the female headers included in the kit. Is there a size best used for this? 20AWG? Do you basically just bend the wire and then cut it a bit short, using the other end to connect to the pots/jacks? I would love to see a picture of how this connector is supposed to look.

More importantly, I don't understand how I'm supposed to hook up the A-100 case to the PCB. Do I snag the typical 16 pin connector from somewhere like Analog Haven and simply insert hookup wire into the appropriate voltage terminals?

Last question: I don't think I'll be able to afford a typical front panel right now, so I was wondering if it would be possible to build a cheap one out of cardboard and then swap out the panel when I can afford one? Can't I just take the knobs off the pots and pull them out?

I appreciate any help you can give me, even if it's just pointing me in the right direction.

P.S. I plan on documenting this quite heavily for users like me who have never built a modular and don't want to go digging through pages.

[Danno Gee Ray]

I'll take a stab at some of this.

I would recommend 22 guage hook up wire for this. you can use standard ribbon cable if that's what you have. To use ribbon cable, just separate the wires at one end for about a half inch or so. Strip each wire, and crimp on the pin for each one. A small touch of soldert can also be used to ensdure a good connection. Don't use too much solder. Once the pins are all on the wires, insert them into the connector per instructions. The other end of the ribbon cable gets the wires separtated and stripped, then soldered to the pots or switches/jacks as needed.

As to hooking up the A-100 case, look up the standard Doepfer or Eurorack power Connector to see how its it arranged. You may need to build an adapter cable to go from the Doepfer power connector to the input power connector of the SN voice. If I'm not mistaken, the SN Voice is designed to work on +- 15 VDC. Eurorack / Doepfer is +- 12VDC. You may need to check with State Machine (Bill Manganaro) to see if this module will work at 12V.

Front panels can be made of almost anything you want them to be. Try going to a hobby store and seeing if they have 0.062 aluminum sheet in a size that can be cut down to the size panel you need. It shouldn't be more that 5 bucks or so. You can always use carboard to mock up your design, and then move the parts to a better material later. Just remember, that pushing patch cables into a cardboiard front panel can be challenging due to the flexing of the4 panel.

Hopefully, more people will chime in with details I haven't provideed.
Good luck with the project.

Dan

[MCDELTAT]

Thanks for your reply.

'Strip each wire, and crimp on the pin for each one.' Can you elaborate on this? It seems you suggesting I solder one end of the ribbon cable directly to the male headers, which doesn't seem right because the kit came with female headers that snap onto the male ones.

As per the SN Voice working at +/- 12V. I've read on another thread that it works almost perfectly without any modification, the only error being that the triangle wave offset was high. To fix this they changed one resistor from 22k to 14k and it worked. I'm more concerned about how the ribbon cable, which for Doepfer is the Dual-Row 16Pin connector, fits into the equation of powering the module.

As for the cardboard. I'm fine with minor inconveniences for the time being... see the problem here is that in less than 2 months I'll be leaving to Uruguay for 2 years, leaving all my stuff in the U.S. So although I want to finish this kit, I don't like spending money that I don't have to.

EDIT#2:Found a good looking place to grab ribbon cable. http://www.hcm.hitachi.com/electronic_ribbon_cable/100-stranded-wide-pitch-ribbon-cable.shtml
They don't list prices though, so you'll have to contact them directly for a quote.

[Danno Gee Ray]

Can you post a photo of the header you recieved with the kit?

[MCDELTAT]

Yeah heres two picture of it. Sorry for delay, took me forever to find my camera USB cable haha.[/img]

The photo is of a set of male and female headers. Three pairs such as this came with the kit.

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[Danno Gee Ray]

OK. You have 2 pieces in the photo. The one on the left is called a Header. it gets soldered to the PCB. The other is the housing for the connector. You should have gotten a string of Pins that look like a weird machine gun belt like thing. Silver metallic color. Find those, and post a photo of them. I'll then use the photo to describe how to use them.

[MCDELTAT]

Ha. I was trying to figure out what those were. This is why noob things like this need to be documented. Here's the photo, again theres three sets of these.

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[Danno Gee Ray]

I have taken excerpts from Stae Machine's most excellent instructions for the Quad Bass ++ and edited them to apply to the SN-Voice. As Bill is always ready to help the DIY community, I hope I have not crossed a line by doing this. If this is considered a breach, please MODS correct me as is required.

Here is the modified text from State Machine...

"Each cable consists of three elements:

The housing, which is a shell that the cables are “plugged into and which connects to the proper
connector on the PCBs. There two types of headers used in the SN Voice module, they differ
by the number of wires they will accommodate. They are six position headers with 0.1” spacing
and four position headers with 0.156” spacing. The header pins are crimped or soldered or
crimped and soldered to the ends of the wires, depending on your chosen technique. Generally 22
gauge or 24 gauge braided wire is required. Do not use solid core wire.

Housings and Pins

First of all, one must be aware that the housings will plug into the PCB headers in only one
direction – this ensures the wire that is to attach to pin 1 of the PCB connector is the correct wire.
So, you must become aware which “hole” in your housing will mate with pin 1. On the back of the PCB,
you will notice that each connector has a square pad to designate pin 1 of the connector.
The PCB silkscreen also designates where pin 1 is also so please pay attention. The connector is
keyed so that the housing can only be plugged in with one orientation. In other words, the header
is keyed so that the housing, which has a mating “key” will plug into it. On the housing, the key is
a ridge running along the edge of the “bottom of the housing”.

Figure 9 Housings and Header Pins

On the opposite side of the housing is a slot for each “hole” or terminal in the housing. These
slots run along the bottom. The header pins, which attach to the ends of the wire, have a small
tab that protrudes from the “back” of the pin. This small tab acts as sort of a fish hook and will
“catch” in this slot when it is inserted into the housing.
Attaching the Pins to the Wires
The header pins attach to the ends of the wires, and are then inserted into the housing. The pins
have a couple of tabs at the top that are intended to be crimped, or folded over the insulation of
the wire. The end of the wire is stripped and tinned, about ¼” from the end of the wire.
This stripped and tinned part is to extend down so the “loop” of the header pin compresses down onto
the bare wire when the wire and pin are inserted into the housing.
Crimping tools can be expensive, though fairly inexpensive types that resemble a pair of wire
cutters are available. In lieu of a crimping tool, many people will fold the tabs over the bare wire
and put a small amount of solder there to hold it in place (a large “blob” of solder may prevent the
header pin from fitting into the housing). Generally, during the SN Voice build process, it was
found that the small amount of solder made a much more reliable connection.

Figure 10 Putting The Header Pins On Wires

It’s a very good idea, if at all possible, to use a number of different colors of wire when building
the cables. This helps you to determine very quickly which wire is pin 1, which wire is pin 2, etc.
Otherwise, it’s very easy to become confused which wire is which, and this can lead to errors
when soldering the free ends of the cables to the front panel.
Also, make sure you provide plenty of length for the wires. Make sure your wires are longer than
they should be to accommodate any front panel you choose. By now, you’ve probably figured out
how you’re going to mount the SN Voice PCB in your chassis. You can break the job down
into separate tasks. For example, you can go through task of stripping all of the wires needed and
attaching the pins. Then you can task yourself with inserting the wire/terminal pin into the
housings, and then you can task yourself with creating a neat looking cable by either wire-tying
the cable wires together, or twisting the wires around each other to create a twisted-pair type
thing. However, this last task may need to wait until after you’ve soldered the cables to the front
panel – for now, it may be best to put a nice little twist-tie “collar” onto the cables just above
the housing once the cable is assembled. When you strip the wires, it’s not a bad idea to strip just a
tiny bit of the wire off the end that will connect to the panel. You can then use this exposed bit to
attach a DMM or continuity checker to it and make sure your wire has continuity from the pin to
the end of the wire. A little care at these early stages can save a lot of headache at the final
assembly and test stage of building your SN Voice.

Figure 11 Pins Orientation Before Insertion Into the Housing

Once you’ve got the terminal pins attached to your wires, you can insert them into the housings.
When you insert the pins into the housing, make sure that little barb on the back of the pin is
oriented towards the side of the housing that has the small “window” in it – the barb is designed
to “catch” in that window like a hook in the mouth of a fish, and make it harder to yank it out at a
later date. When the pins are inserted into the housings, there should be the sensation of a soft
“click” – this is a good sign that you’ve done a good job getting the pins on the ends of the wires.

Figure 12 Inserting Pins Into the Housing

Remember that “loop” on the pin must not be crushed or misshapen – it is intended to compress
down over the wire, making a good connection, and also provides a certain amount of tension that
helps hold the pin in the housing. And, again, too much solder (if you put solder on) or solder in
the wrong place can inhibit the actual installation of the pin into the housing."[img][/img]

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[Danno Gee Ray]

You will have to cut each pin from the Bandolier in order to use them.
The end that is cut off the runner is the end where the wire goes.
Hope this helps.

[MCDELTAT]

Yes this helps quite a lot. Thanks so much, this solves all my questions, so now it's time to start building!

If it isn't too much trouble can you either link the thread where this was found or find the pictures referenced? They say their not available for download anymore.

[Danno Gee Ray]

I wil reatach them to this post.

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[Captain Biscuits]

The quad bass ++ docs are available to download in this thread http://electro-music.com/forum/topic-39402.html and include a long description of making ribbon cables.

The whole crimped pins thing is an absolute pain the first time you do it. I went through what you're going through now two or three months ago. Eventually it all becomes clear. It's still very fiddly but you will master it.

Having got the quad bass ++ together I'm bracing myself for the Klee!

Hope you get your ribbon cables together okay. They are quite satisfying once you get the hang of them. I seem to remember there was a discussion somewhere where someone was just buying them ready-made pretty cheaply and was asking why anyone would go through the pain of building them. I guess it builds moral fibre or something

Cheers

Ian

[State Machine]