Miasma: Function Generator (DIY PCB based on Befaco Rampage)

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TheMentat
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Post by TheMentat » Sat Jun 23, 2018 11:18 pm

Buttons ARE toys wrote:Super-duper-gigantic thanks to Altitude909!!! I had no idea when I requested this build back in February that it would be such an ordeal and he handled the whole process professionally and skillfully. Having a blast with this lovely module!
:party:

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Holy fk... that was a commissioned build?

Big props to him!

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ChartreKhan
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Post by ChartreKhan » Fri Jun 29, 2018 1:58 am

Sin_Phi wrote:@ChartreKhan do you know which outputs you think should be buffered? Is it just the main outs, or also the max/min etc. Doing just the main is pretty easy with an opamp on the IO board, otherwise might need to buffer before the balance pot and that could have some unintended consequences besides a board routing nightmare. I would probably make the buffer circuit optional.
a bit late, but just the main outs. The other outputs are all sufficiently buffered, they only have LEDs coming from them.
https://aags.bandcamp.com - Amamanita Axaxaxanax Glass Seer, noise/drone/glitch with modular
https://chartrex.bandcamp.com - old solo synth music
https://www.etsy.com/au/shop/ChartreArts - Etsy Store where I sell pre-built modules, altho dont have any up rn

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ZZ Ardoz
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Post by ZZ Ardoz » Fri Jun 29, 2018 12:16 pm

So are there any mods that need to be made on the currently-available files in order to make this work? Or is it good to go?

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Altitude909
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Post by Altitude909 » Fri Jun 29, 2018 1:19 pm

good to go. I have a couple sets of boards for sale

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ZZ Ardoz
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Post by ZZ Ardoz » Fri Jun 29, 2018 1:51 pm

Altitude909 wrote:good to go. I have a couple sets of boards for sale
Thanks Raph!

nutate
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Post by nutate » Mon Jul 02, 2018 9:54 am

Posting so I have a post count of 1 to DM for a possible set of boards. Thanks.

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TheMentat
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Post by TheMentat » Wed Jul 04, 2018 1:11 am

Where did that panel come from? Any more kicking around?

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Altitude909
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Post by Altitude909 » Wed Jul 04, 2018 6:36 am

TheMentat wrote:Where did that panel come from? Any more kicking around?
i had FPE make it. it was a one off

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Sin_Phi
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Post by Sin_Phi » Thu Jul 05, 2018 11:16 am

There is a vector image file on the modules web page that you can use to get one laser cut for pretty cheep. Alternatively if you are already ordering PCBs then the panel can be had from the same fab for ~$30 with the panel design files included in the zip. That one is double sided. Ones side has the 4QX legend and the other SUM depending on if you use the AD633 or just take the summing output. It would look something like this with black solder mask:

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schnitzelbub
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Post by schnitzelbub » Fri Jul 06, 2018 9:23 pm

:hail: :hail: :hail: :hail: :hail: :love: :love: :love: :love:

IImyment
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Post by IImyment » Tue Jul 10, 2018 10:37 am

Hi everyone I just received few sets from the fab. They looks quite good actually but haven't tried yet to build them. If that's OK with Sinphi I d like to sell my left over or trade them. Anyone? Image

IImyment
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Post by IImyment » Sun Jul 22, 2018 9:29 am

Hello, I just run a script to generate a rough helping document for the component. I hope that could be useful to someone else.
Sorry double posted attachment but I can't figure out how to get rid of one on my phone.
You do not have the required permissions to view the files attached to this post.

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Post by Lemmy » Sun Jul 22, 2018 12:38 pm

deleted

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Sin_Phi
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Post by Sin_Phi » Thu Aug 09, 2018 9:24 pm

I have moved to LA and will FINALLY have a permanent address so I can pick this project up again next month. I will be building a round of this iteration (maybe some more silkscreen labeling and some test points).

This project is CC-BY-SA-NC-4.0 so do with it as you please, this is the same licence as Befaco. Please be mindful of the Non-Commercial portion of the license. Any large runs of the boards will not be supported by myself and would not be in the spirit of the license.

If the people who built this version have any feedback I welcome it.

That pdf layout tool is awesome, caught a typo there :|
Last edited by Sin_Phi on Tue Aug 21, 2018 9:36 am, edited 1 time in total.

psynautic
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Post by psynautic » Sat Aug 11, 2018 12:36 am

IImyment wrote:Hi everyone I just received few sets from the fab. They looks quite good actually but haven't tried yet to build them. If that's OK with Sinphi I d like to sell my left over or trade them. Anyone? Image
the faceplate turned out great. did u use ENIG?

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forestcaver
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Post by forestcaver » Tue Aug 28, 2018 2:10 pm

Just verifying before I order some pcbs - are there any issues known about with the files uploaded to the sin phi website (I downloaded them today, 28th August).

Who has built one ? :-)

Thanks a lot....

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Post by Lemmy » Mon Sep 10, 2018 3:49 pm

Here's mine, built with one of IImyment's spare sets of PCBs.
This is a really flexible module, so many possibilities... good job SinPhi and of course Befaco for making and open sourcing Rampage.

Image

@forestcaver, all seems to be working with the published PCBs.
If you're following the BOM on SinPhi's site double check the toggle switches - you need the ones with slim pins, not ones with holes for soldering wires through. I bought those and had to hack them with the snipper to get them to fit the PCB.

@SinPhi, as you were asking for comments... now I have a better idea of how these modules work, I think the extra LED feedback on the Rampage outputs looks pretty useful. I realise you have probably juggled the layout to fit in the CV attenuators. Also I don't find the momentary toggle switch as usable as a couple of push button switches would have been. My toggle switch is stiff which doesn't help.

Can you explain more about the 4QX and how to use it?

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forestcaver
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Post by forestcaver » Mon Sep 10, 2018 5:02 pm

Lemmy wrote: @forestcaver, all seems to be working with the published PCBs.
Thanks a lot Lemmy !! That’s great to know - will get my arse in gear and sort out some pcbs !
(Thanks for the info on the switches - I *think* I have a fair few switches that will fit anyway.... will double check....)

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Sin_Phi
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Post by Sin_Phi » Tue Sep 11, 2018 12:16 am

I also have a batch on order and will be building myself 4 at least, 2 with the AD633 and 2 summing. Going to try out some different timing caps as well.

@forsetcaver didn't want to comment about everything working until I built this version myself, but a with few people have having successful builds there is some confidence you too could have success...

@Lemmy, congrats on the build! It looks great. The 4QX is a 4 quadrant multiplier (aka ring modulator) if you have the AD633 installed. There is a lot out there on how those work that explains it better than I could. You may need to play with the value of R67 to get a louder signal. If you went the route of the jumper then it is actually the inverted sum of the left and right sides.

I don't plan on doing any more lights or controls, already a tight build with the attenuverters. That center toggle saves a ton of space. Curious as to why you found the buttons better? Is it being able to trigger both at once?

Totally forgot about the switches, I am just used to crushing them with pliers to fit and thought nothing of it (easier to crush than to cut). I will see If I can do a revision to some slots after I build mine.

Any other BOM issues? I will get that updated ASAP. Hopefully I will remember get some decent build photos when I do mine and make a real guide.

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forestcaver
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Post by forestcaver » Tue Sep 11, 2018 3:17 am

Thanks Sin Phi!

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Post by Marizu » Tue Sep 11, 2018 3:45 am

Lemmy wrote:I think the extra LED feedback on the Rampage outputs looks pretty useful.
Output LED's are useful on function generators. Although it's not always ideal, I sometimes use FSS AJAKs when I patch something and it isn't immediately clear what is going on. They would be easy to make but the product is robust and good looking.
http://www.futuresoundsystems.co.uk/

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Post by Lemmy » Tue Sep 11, 2018 4:18 am

Sin_Phi wrote: @Lemmy, congrats on the build! It looks great. The 4QX is a 4 quadrant multiplier (aka ring modulator) if you have the AD633 installed. There is a lot out there on how those work that explains it better than I could. You may need to play with the value of R67 to get a louder signal. If you went the route of the jumper then it is actually the inverted sum of the left and right sides.
Ah, OK, I will experiment with it and report back if I try tweaking R67
Sin_Phi wrote: That center toggle saves a ton of space. Curious as to why you found the buttons better? Is it being able to trigger both at once?
I see that it's a layout issue and it would be a shame to make the module wider. There might be scenario where one would want to manually trigger both simultaneously, but for me it's more about ergonomics. Pushing the switch sideways is much trickier than jabbing a button with your finger tip, specially if you are trying to sync to a beat. But there's always the trigger input for that, so it's probably not such a big deal.

Also I will need to check this on the oscilloscope but the output from the OUTs (triangle or saw) seems quieter and duller than from the RISE / FALL (square). I realise that Triangle waves are perceptibly quieter than square waves, and have noticed this issue on other VCOs I have, so maybe I am particularly sensitive to this? (It may also be that my hearing is borked in certain frequencies.) Similarly when running an audio signal to IN, the output from OUT seems to have lost a lot of top end and amplitude even when rise and fall are set to minimum. I'm guessing that these are not really the primary functions of the modules and it is more for wrangling CVs, which it excels at, but it would be nice to know if this is expected behaviour.

Thanks!

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Post by Lemmy » Tue Sep 11, 2018 4:20 am

Marizu wrote:
Lemmy wrote:I think the extra LED feedback on the Rampage outputs looks pretty useful.
Output LED's are useful on function generators. Although it's not always ideal, I sometimes use FSS AJAKs when I patch something and it isn't immediately clear what is going on. They would be easy to make but the product is robust and good looking.
http://www.futuresoundsystems.co.uk/
Great idea. I think there are also patch cables with built-in LEDs? I will look into it.

mcnys
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Post by mcnys » Tue Sep 11, 2018 6:43 am

you can build them yourself...it's very easy

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MatrixModulator
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Post by MatrixModulator » Wed Sep 12, 2018 1:03 am

May i ask where you buy the BCM857DS135 and BCM847DS135?
Seems out of stock everywhere :S
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