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DIY Eurorack prototyping kits
MUFF WIGGLER Forum Index -> Eurorack Modules Goto page 1, 2  Next [all]
Author DIY Eurorack prototyping kits

synthomaniac

Hi all,

I've been quiet for the last year finishing off my music tech degree but have been a busy bee for the last month. I have invested in CAD software for front panel artwork, schematic capture, simulation and PCB design. I am producing a set of kits to allow experimenters and DIYers to easily make one-off or prototype Eurorack modules. They include PCBs, pots, brackets, 3.5mm jacks and ribbon cables. Have a look at my new blog on:

http://synovatron.blogspot.com

I am also going to produce a versatile voltage processor module entitled "CV Tools" in a month or so; a preview of its front panel is shown on the blog. The panel is an overlay on a Schaeffer made 3U panel. I am thinking of offering front panel overlays as a low cost design service.

The DIY kits will be ready in a few weeks. More details then. Please feel free to ask questions and make comments and suggestions.

Cheers
Tony


Monobass

nice idea


Hi5

count me in


RichyHo

Nice idea Tony, I'll be keeping an eye on your Blog - Good luck!


baboo

Hi,
that seems awesome screaming goo yo I've been thinking about going DIY as I'm not expanding my system right now but I'd like to dig deeper in electronic instruments. Complete kits kina put me off for some reason, maybe I'd like to figure things out myself instead of someone doing it for me.

Are you planning to post some resources about designing electronic circuits on your blog? You know , basics that would attract non-DIYers to designing their own stuff? Or you are doing this for people with more experience?


Veqtor

+1 on awesomeness!

Someone really needed to do something like this and I'm glad you did!


Monobass

an idiots guide to turning synth schematics into working modules would be great... no mean feat I know...


Jason Brock

So if I had a panel designed, I could order a one-off production panel from you made of metal with silkscreen graphics, etc.? If so, that's exactly what I have been looking for.

It would be great to have high quality panels for DIY kits. And maybe you could keep a library of such designs if someone else wanted to order a copy for their DIY kit too (sort of like an "open license" agreement for the art if the designer chooses to allow that).


Cat-A-Tonic

The CV Tools looks good.
Very much like the Fonitronik Attenuverting Mixer, but with slew too.
+/- voltage LEDs would probably be more useful than sum indicators.


synthomaniac

Thanks for the interest and encouragement guys.

For Baboo and Monobass: I'd like to put some learning and data resources around the DIY kits but I'll have to assume a base level of knowledge and I'm not sure where to pitch that yet. The last thing I want anyone to do is have a bad experience that resulted in their synth going up in smoke. Here's a couple of questions to try and gauge where potential constructors are at (remembering in '73 I knew nothing at all but on the basis of attempting to let the smoke out of many synth designs I got employed in electronics and eventually became a designer):-

Can you use a soldering iron and hand tools sufficiently well?

Can you use a multimeter or scope? Do you have either?

Do you understand Ohm's law, RC timing circuits, source and load resistance?

Do you know about op-amps and how the various configurations work? i.e. can you calculate gain, input resistance etc?

You can see the kind of things I need to think about!


Soundxplorer: I was thinking about providing a front panel overlay which you can fit to a metal panel you have made or can get made - I use Schaeffer in Germany - it's an online service but a bit pricey. I can certainly do this on your behalf. The panel overlays are not silk-screened, they are a high quality graphics printed on a a plastic self-adhesive film. (That's why they are going to be cheaper than silk-screening) I have updated the blog with regard to these questions.

Cat-A-Tonic: The emphasis is on versatility with CV Tools - the sum LEDs indicate how each of the channels link together - putting a patch lead into Out2 for example will make the LED below go out indicating the Out3 is disconnected from the channel above - so this could be 2 x 2-channel mixers, or 4 separate polarising level control channels or a 2 channel mixer and 2 separate polarising level controls or a 4-channel polarising mixer. Each channel has gain (x2), polarises and/or offsets depending on which inputs are connected. It does loads!! But I do take your point about +/- LEDS and have been thinking about those but they would be required for each channel as they can be used separately. This is still in development so it's good to get this kind of feedback - thanks,

Thanks again for all your thoughts and ideas - check out the updated blog.

Best regards
Tony


Monobass

synthomaniac wrote:
Can you use a soldering iron and hand tools sufficiently well?


Yes, very well.

synthomaniac wrote:
Can you use a multimeter or scope? Do you have either?


yep.

synthomaniac wrote:
Do you understand Ohm's law, RC timing circuits, source and load resistance?


yes, no, rusty!

synthomaniac wrote:
Do you know about op-amps and how the various configurations work? i.e. can you calculate gain, input resistance etc?


I've read about it but have never done anything in practice.


HueMonContact

Sounds great! I'm really interested in more DIY options for eurorack.


bensaddiction

I really dig the perfboard pcbs designs you have there with the correct spacing etc to mount pots, switches, jacks etc.


I'll take 10 of each please!!!!! & thats just for this month

Spacing and placement of panel components so that you can mount directly to the PCB is really difficult for a DIYer doing Euro using a PCB app like EagleCAD.

And If you decide to mount it off the board then you have to think up ingenious brackets and other pcb support schemes. Personally I just hope that Fonik has already made a press 'n peel design of what ever I'm trying to build.


Your design look like it would conform to a certain standard too yeah? The busy 5 pots in a row standard like deopfer? I like that as it allows slightly easier front panel designs as you know where things are supposed to line up.

I really like the 2 pcb designs you have there. It makes for a really fast way to get something together to prototype a new filter etc. I have a feeling I might see if I can get a utility front panel made up with lots of holes for the pots and a row of holes or even a big slot for the jack/switches pcb so that it can accept lots of different variations of designs using your prototyping pcb board. That way you could rapidly build something and have it in your rack in a tweakable state quickly - while you wait for a more permanent front panel to be made.

If I was to make 1 comment... I like the decoupling caps, but lots of DIY-ers also tend to put in 2 ferrite beads or suitable resistors on the the power lines as well to provide some further hum minimisation. But that could easily just be put into the board elsewhere I suppose. That is my only comment on your design - well done.

Let me know if you go ahead with manufacturing some. They would no doubt be very handy this summer (southern hemisphere) I already need 2 of you jack pcbs to make some buffered multiples


rico loverde

great idea. I can follow a wiring diagram and read a schematic but the actual creation of new circuits is beyond me. Something Id love to learn though. Maybe a series of very clearly instructed components that could be wired together to form diff projects... a basic osc plus mods for bells and whistles, basic sequencer, cock circuits, etc etc. Again since I dont know much about the creation Im not sure how hard this would be.

Will def keep an eye on yr site!!!!


synthomaniac

bensaddiction wrote:
Your design look like it would conform to a certain standard too yeah? The busy 5 pots in a row standard like deopfer? I like that as it allows slightly easier front panel designs as you know where things are supposed to line up.


Yes the 5 pots and 5 jacks are on the same spacing to try and standardise and simplify the panel design. The pots must be separated horizontally from the jacks by 20mm or more to clear the underside of the PCB.

bensaddiction wrote:
If I was to make 1 comment... I like the decoupling caps, but lots of DIY-ers also tend to put in 2 ferrite beads or suitable resistors on the the power lines as well to provide some further hum minimisation. But that could easily just be put into the board elsewhere I suppose. That is my only comment on your design - well done.


Thanks for the feedback, it's a fair point too however I have never experienced any internal EMC problems including hum. So what sort of problems have people been experiencing? It would be easy enough to cut tracks and insert ferrites or resistors and further decoupling caps too. I will look at the for Rev 2 designs if these go well and it looks like people are really interested!

bensaddiction wrote:
Let me know if you go ahead with manufacturing some. They would no doubt be very handy this summer (southern hemisphere) I already need 2 of you jack pcbs to make some buffered multiples


The boards are on their way to me now, 50 of each type. The components (pots, brackets, jacks) are already in stock so I just need to put the kit and data packs together. I'll anounce all the info as soon as I can.

Thank you so much for your comments and encouragement.

Cheers
Tony


mckenic

Watching this with great interest!

thumbs up


synthomaniac

rico loverde wrote:
.....Maybe a series of very clearly instructed components that could be wired together to form diff projects... a basic osc plus mods for bells and whistles, basic sequencer, clock circuits, etc etc. Again since I dont know much about the creation Im not sure how hard this would be....


Well this sounds like a good way of getting people started in understanding the circuits involved and helping to pave the way to you designing your own circuits. In my case there was a lot of trial and error, mainly error, but that's how you learn - figuring out why something doesn't work is the best lesson and it's a real blast to get something working.

Maybe a simple multistage project using a kit and instructions is a good way forward - this could be a lot of work for me but I'll give it some thought. Any other project suggestions are welcome e.g. buffered mult (1 in 4 out).

Thanks for your ideas.
Tony


bensaddiction

@ Synthomaniac per ferrite beads & EMC issues.

I am sure your right about this, I just throw them in anyway as it can't hurt plus I got a bunch from a surplus supplier so I need to get through them. Also my gear is always near some vintage amps with decrepit transformers that literally buzz from the outside. So, this paired with growing up in a house where my father's CB and HAM radio used to come across through the T.V. while watching the Simpsons like the voice of God has me being overly cautious of HF interference, whether irrational or not.

But like you said you can always cut tracks to put your own in. Don't change your design because of me lol


I only have 1 further question. The pcb designs seem to incorporate some power bussing yeah? Are the pcbs still able to function if you cut them? e.g. cutting 1 or 2 pots off the top so that you can hand wire some jacks or switches above or down below? Can you just jumper them with some wire to achieve the same? It just seems that if they could some how be modularised a little bit then they really would be the answer to my prayers. Maybe rev2?


synthomaniac

bensaddiction wrote:
@ Synthomaniac per ferrite beads & EMC issues.

I only have 1 further question. The pcb designs seem to incorporate some power bussing yeah? Are the pcbs still able to function if you cut them? e.g. cutting 1 or 2 pots off the top so that you can hand wire some jacks or switches above or down below? Can you just jumper them with some wire to achieve the same? It just seems that if they could some how be modularised a little bit then they really would be the answer to my prayers. Maybe rev2?


Sure you can cut the PCB down to size, if you are careful then the cut off part can still be used e.g. cutting down through the holes in column 16 to remove the top two pot positions. Just make sure there is a clean cut and there is no copper shorting the busses together. I aim on providing the kits with the pots, brackets and jacks unsoldered so if you want to leave out some postions to fit switches, panel jacks above or LEDs on the PCB you can - in the case of components fitted to the front panel such as a toggle switch you can still wire down to the board directly or connectorise via Berg style header pins - the row nearest the pots and the two outer rows have larger holes to accomodate headers (as does the jack board).

As soon as I get the PCB delivery and am happy with the quality I'll build some examples and post pictures of them on the blog to give you an idea of what is achievable.

Cheers
Tony


synthomaniac

Thanks for the feedback. That's a good starting point to help me pitch the level of help, guidance notes and types of resources required. As you say no mean feat and I'll start to think about how best to go about this. Also checkout my post to Rico about projects.

Cheers
Tony


amsonx

Count on me, i 've great interest on this.


fonik

Cat-A-Tonic wrote:
The CV Tools looks good.
Very much like the Fonitronik Attenuverting Mixer, but with slew too.

indeed grin
DC or AC coupled?


synthomaniac

fonik wrote:
Cat-A-Tonic wrote:
The CV Tools looks good.
Very much like the Fonitronik Attenuverting Mixer, but with slew too.

indeed grin
DC or AC coupled?


All DC coupled as it is mainly aimed at CVs and has linear pots but still can be used for audio at a push. Just working on an update to include +/- LEDS too for each channel plus an expansion port for each channel at the rear to be used in conjunction with a sequencing add-on that is in development.

The DIY PCBs arrived today and look very good, nice quality - I'll put some piccies up on my blog when I get a chance hopefully in the next 24hrs.

Cheers
Tony


daverj

bensaddiction wrote:
I like the decoupling caps, but lots of DIY-ers also tend to put in 2 ferrite beads or suitable resistors on the the power lines as well to provide some further hum minimisation.


Well..... Actually, ferrites won't do anything about hum, unless the hum is characterized as a very high frequency modulated by hum (which certainly does happen). The 3db rolloff of the typical 10 ohm and 10uF cap power filter is around 10Khz, so it's also not very effective against hum.

Both of them do add filtering against spikes and high frequencies going in and out of a board. The ferrites really only prevent extremely high frequencies (up in the Mhz range) and very short current spikes like what happens when digital chips switch states. The resistor (plus the cap) can filter audio rate spikes and oscillations. It can also act like a current limiter and even as a fuse to some degree when there is a short on the board.

Of course the resistor can also cause the power rail to fluctuate a bit as current changes. (10mv/ma for a 10 ohm) For a board drawing 25ma, that's 1/4 volt.

Ferrites have zero ohms at DC, so won't cause voltage fluctuations. But also don't filter low frequencies. A ferrite acts sort of like a frequency controlled resistor. At DC it has zero ohms. At 50Mhz it might be 100 ohms (values vary by part number). The important feature of a ferrite is that it can prevent high frequency spikes from entering your board, plus prevent spikes created by your board from leaving the board and affecting other modules.


synthomaniac

Hi Fonik,

I just checked out your site, very nice! I am doing slightly different things with the CV tools module, for instance CV tools can be configured as two 2-input mixers plus the slew limiter. Our circuits use a different approach to polarising and summing; I was mainly aiming at combining features of several Doepfer modules into one.

Good to see what you have done, looks like fun.
Cheers
Tony

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