flickr by kb6402000(click for more)
"My DIY expansion box for the Kraftzwerg. It features 3 multiples and 4 attenuators.
Since this is a passive box, not PSU is required. It adds some missing features to the MFB. Total cost for parts including box: $20 (+6 hours labor). A similar box using Doepfer modules would have cost about $225."
Update 3/11/12: pic of the underside added. You'll also find a link to the schematics and additional details in the comments below.
hello,
ReplyDeletei'm pretty impressed about your diy project. could you please provide the schematics and the components list?
i also own a lovely mfb kraftzwerg and would like to expand the beast. my emailadress is nisabuur@yahoo.com
many thanks in advance!
:)
@pneumachina
ReplyDeleteThanks! I sent you an email with the details.
hi, i'm getting a kraftzwerg myself, i stumbled across this post and this seems like a great expander, and cheap! could you please email me schematics and a component list to flying_fishcake@hotmail.com ?
ReplyDeletethanks, and keep going with the DIY stuff, it's way cool ^_^
Tom
Although these comments are a bit older I have the same request: Could you send me the schematics?
ReplyDeletecarlovauxhall@gmail.com
Thanks
The schematics for the attenuators were "borrowed" from Doepfer actually.
ReplyDeletehttp://www.doepfer.de/DIY/attenuator.gif
The value of the potentiometer is 50k ohms linear. I could not find linear pots, so I used Logarithmic instead and it works fine. They're just a little more sensitive towards the end of their travel.
Each of the 4 attenuators on my box is separate from the others. Of course you can make the number of attenuators you need, if you want more or less than 4.
The Multiples are very easy to do: just connect the number of 1/8" (3.5mm) connectors you need together. Be careful not to invert the signal and ground pins: all the signal (tip) connected together and all the ground (sleeve) together.
Again, I choose to make 3 multiples with 4 connectors each, but you can make more, or less, with more connectors each if you want. But the minimum number of connectors for each multiple will be 3. Following many designs by Roland 100m, and
other modular synths, I choose to include 4 connectors for each of the 3 multiples. That gives me 1 in and 3 outs. I you need more than 3 outs, simply use another multiple!
Here's the parts list for my box with 4 attenuators and 3 (1 input, 3 outputs) Multiples: (I live near Montreal Canada so these are what I could find at my favorite electronics supply store called Addison Electronics)
1/8" (3.5 mm) mono female connectors (qty:20)
50k ohms linear pot (log will work also) (qty:4)
plastic knobs (with screws so it will fit any type shaft) (qty:4)
general purpose plastic casing with aluminum front panel (qty:1)
Small gauge wiring (I use size 20)
That's it. Oh yeah, some blue Dymo labels too.
I hope this helps, and have fun making it.
Alain.
Just to add, I used the aluminum front panel as common ground, reducing greatly the number of wires to connect.
ReplyDelete