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

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strewya
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Post by strewya » Sun Mar 31, 2019 2:23 am

KT wrote:does someone, preferably in Europe, has a spare pcb/panel? A silver pannel would be super
I've just ordered some. I'm London based .

If you still need it, let us know.

Cheers

merlin
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Post by merlin » Sun Mar 31, 2019 3:08 am

strewya wrote:
KT wrote:does someone, preferably in Europe, has a spare pcb/panel? A silver pannel would be super
I've just ordered some. I'm London based .

If you still need it, let us know.

Cheers
I would also be interested if you have a spare set, l’m located in the UK.

Thanks,

Karl

merlin
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Post by merlin » Sun Mar 31, 2019 3:14 am

strewya wrote:
KT wrote:does someone, preferably in Europe, has a spare pcb/panel? A silver pannel would be super
I've just ordered some. I'm London based .

If you still need it, let us know.

Cheers
I would also be interested if you have a spare set, l’m located in the UK.

Thanks,

Karl

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KittenVillage
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Post by KittenVillage » Sun Apr 14, 2019 12:50 am

I was going over the BOM and made a google spreadsheet for it.

I have a couple of questions though.

I couldn't see part number C0805C1045RAC for C6,8,9,10. No google hits for that part number. I went with Mouser part 77-VJ0805Y104JXXCBC

C3, 13 are listed as a 0603 part number instead of an 0805. I went with Mouser part 77-VJ0805Y473JXJCBC

R56,57 are still listed as 110k instead of 100k in the PDF BOM.

Maybe the PDF can be updated with a note as to which version of the board it's for? Or maybe a date of revision so everyone knows it's been updated?

I'm looking forward to this build in a few weeks!

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Sin_Phi
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Post by Sin_Phi » Mon Apr 15, 2019 9:23 pm

Got the BOM updated, finally. PC died on me so has been a slow return of data recovery.

The capacitors are all just 0805 C0G/X7R of suitable quality. I think I went with 5% tolerance and TDK for most just for consistency. Part numbers change by batch so moving target on part numbers, just get a near match.

PDF BOM is for all versions of the board everyone has (except Altitude909 who had the misfortune of working on my prototype).

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KittenVillage
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Post by KittenVillage » Tue Apr 16, 2019 1:14 pm

Sin_Phi wrote:Got the BOM updated, finally. PC died on me so has been a slow return of data recovery.

The capacitors are all just 0805 C0G/X7R of suitable quality. I think I went with 5% tolerance and TDK for most just for consistency. Part numbers change by batch so moving target on part numbers, just get a near match.

PDF BOM is for all versions of the board everyone has (except Altitude909 who had the misfortune of working on my prototype).
Thank you very much for the update!

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MatrixModulator
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Post by MatrixModulator » Wed Apr 17, 2019 12:03 am

So i just finished 2 builds, both does not cycle when i push the trigger switch with the cycle switch activated on the right channel but both have the left channel working fine. I checked soldering, emplacement of each parts and orientation 3 times now, what could cause this? :hmm: It works fine, it just doesnt cycle by itself like the left channel :( (using the last rev 1.04 main board and IO board that has the bigger holes for the switches)

Thanks :)

Edit: see below, fixed it, my mistake :S
Last edited by MatrixModulator on Thu Apr 18, 2019 12:39 am, edited 2 times in total.
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OIP
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Post by OIP » Wed Apr 17, 2019 1:10 am

sounds like it could be an issue with the switch itself? especially if the trigger input itself works. it's an on/on momentary. if you have some leads you should be able to test what happens just sending 12V to the switch pad of the left channel - that's all the switch is doing.


in related news, i checked the left rise CV pot behaviour which has been mentioned a few times and on mine too it's backwards - looking at the schematic i think this is how it's wired (321 as opposed to 123 like the rest). i'm not barking up the wrong tree right? easy enough fix in existing units.


and finally, i've been using two of these builds for ages now and love them, but still baffled by the cycle input. it seems to just lock after one switch rather than switching anything on and off, is there a 'normal' way to use these? does the physical cycle switch have to be in the 'off' position?

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Sin_Phi
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Post by Sin_Phi » Wed Apr 17, 2019 12:38 pm

The not cycling issue is something I have had on a few builds and sometimes reworking has brought it back, but unfortunately 2 of mine never got up and running. The one thing I haven't tried yet is replacing the timing caps. Have tried swapping transistors, matched pair and the top op amp with mixed success in the past. This is not unique to my version of this, the Rampage has similar issues if you see other posts on this forum. Haven't seen a single solution present its self in any of those threads.

Ah does look like that is 321 not 123, was looking for other less obvious stuff. I could do a quick revision on that (well not quick, I have to redo a lot with the hard drive failure and KiCAD update). Never observed the behavior in my builds (older revisions), must have messed it up at some point when I was fixing something else.

I think you need the cycle switch off from what I remember. Never tried the inverse with it on and the gate suppressing cycle.

jakobprogsch
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Post by jakobprogsch » Wed Apr 17, 2019 2:29 pm

I had issues with EOC triggering external stuff when fall speed was set to low values on my Rampage. The fix, or rather alternative build, was to replace C23 and C24 with wires and remove R89 and R90 (in the Rampage schematic). This way you get a more Math like EOC that is always on if the EG isn't "doing something" instead of the pulse that default Rampage produces. It also results in it cycling the moment you flick the switch without first having to press the trigger. Maybe that would also help in this case?

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MatrixModulator
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Post by MatrixModulator » Wed Apr 17, 2019 6:50 pm

Edit:deleted, not useful information poluting this thread lol
Last edited by MatrixModulator on Wed Apr 17, 2019 11:47 pm, edited 1 time in total.
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MatrixModulator
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Post by MatrixModulator » Wed Apr 17, 2019 10:41 pm

Edit:deleted, not useful information poluting this thread lol
Last edited by MatrixModulator on Wed Apr 17, 2019 11:47 pm, edited 1 time in total.
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MatrixModulator
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Post by MatrixModulator » Wed Apr 17, 2019 11:46 pm

Ok nevermind got it, stupid me again... i used 100k instead of 10k near the EOC socket of the right channel. All good now! :omg:

Sorry about that
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okelk
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mistake fault!

Post by okelk » Tue May 07, 2019 9:19 am

I just noticed a mistake (?) in the BOM. There are too many switches on there.
It is supposed to be

2x ON-OFF-ON
and
1x (ON)-OFF-(On)

right?
there are also some ON-OFF switches on there....

I ordered myself some PCBs and am really looking forward to the build!
Keep up the good work!

EDIT: irrelevant question
Last edited by okelk on Wed May 08, 2019 3:20 am, edited 1 time in total.

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MatrixModulator
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Re: mistake fault!

Post by MatrixModulator » Tue May 07, 2019 12:07 pm

okelk wrote:I just noticed a mistake (?) in the BOM. There are too many switches on there.
It is supposed to be

2x ON-OFF-ON
and
1x (ON)-OFF-(On)

right?
there are also some ON-OFF switches on there....

I ordered myself some PCBs and am really looking forward to the build!
Keep up the good work!

The BOM is correct, theses on-off switches are for the cycle on or off at the left and right of the module.
ImageImageImage

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okelk
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Re: mistake fault!

Post by okelk » Wed May 08, 2019 3:19 am

MatrixModulator wrote: The BOM is correct, theses on-off switches are for the cycle on or off at the left and right of the module.
:doh:

Thanks.
You won't believe how long I was staring at the panel not finding those switches..

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MatrixModulator
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Re: mistake fault!

Post by MatrixModulator » Wed May 08, 2019 11:30 am

okelk wrote:
MatrixModulator wrote: The BOM is correct, theses on-off switches are for the cycle on or off at the left and right of the module.
:doh:

Thanks.
You won't believe how long I was staring at the panel not finding those switches..
All switches are using the same image on this one from his site.
http://www.sinphi.com/synths/miasma/400_Miasma.png
Happy building! :nana:
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wtk
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Post by wtk » Fri May 24, 2019 2:41 pm

just finished mine, thanks
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shiftr
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Post by shiftr » Thu May 30, 2019 4:12 pm

Does anyone have some PCB's left for this one?

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FetidEye
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Post by FetidEye » Fri May 31, 2019 4:07 am

yeah ,. pm me

shiftr
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Miasma PCB

Post by shiftr » Sat Jun 01, 2019 4:33 am

oops :razz:

wongecho
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Post by wongecho » Wed Jun 05, 2019 2:56 pm

anybody in europe (preferably berlin) has any pcbs + panel left?

wtk
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Post by wtk » Fri Jun 07, 2019 3:28 pm

wongecho wrote:anybody in europe (preferably berlin) has any pcbs + panel left?
i have 3 pcb sets and can lasercut you panel

funkytransport
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diodes

Post by funkytransport » Mon Jun 17, 2019 8:04 am

what way around do the 4148 diodes go? the markings on the PCB arent obvious..

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okelk
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Post by okelk » Sat Jun 22, 2019 5:52 pm

I have a problem with my build ( on both channels ).

They don't cycle. The timing cap only charges up to approx. 8.6V. So it never reaches the 10v reference voltage.

Any ideas what the problem could be?

Thanks!

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