[ORDER] SEM VCF for Euro and 5U

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[ORDER] SEM VCF for Euro and 5U

Post by moogah »

EDIT: find the build thread with info here:

Time to make this thing a reality!

This is a PCB of the 2-pole filter from Oberheim's SEM that I got permission from Oberhiem himself to do :)

The board can be built in two different ways, the first is a faithful reproduction of the original circuit, using original components and all the original features.

The second way adds VC-resonance. This changes the character of the res a bit, but generally still brings that classic oberheim sound.

The board can be run on 15v or 12v (with a couple resistor changes)

There is the option to board mount 3 of the pots, or wire them to the panel.

The board is small enough to fit behind the same size panel as Clarke68's dual RLPG .. (how big was that again? 12hp?)

SYNTHCUBE will be stocking full kits (including the PCB!). For this initial run I may sell bare boards myself depending on interest (or maybe I'll just let synthcube do all the selling stuff..)

There will be panels available for MOTM, .com and Euro (Clarke68!) :D :D

Board cost: 15$ + shipping

I'll be sending the files off to fab within a week, no commitments or money is due until I've got the boards in hand, but it's helpful to have a clear idea of how many people want and if they'd rather get a full kit or bare PCB.

Based on this thread, here is the current interest list:

Username Qty
PRe55ue 1
nickster 1
aladan 4
Dego 1
raisinbag 2
limpmeat 1
DannoGeeRay 1
ringstone 4
Barcode 1
LoFi Junglist 4
carynrich 2
sinemod 3
marvkaye 2
wavehead 1
theabsent 1
johnnymayer 1
steffensen 1
brother303 1
NV 1
hv0190 2
keninverse 1
mcop 1
diophantine 2
logicgate 2
simfonik 2
EMWhite 4
aL Pariah 4
iL 2
DreamLost 2
janvanvolt 2
samuraipizzacat29 4
low-gain 4
revok 1
Monobass 2
xi-bot 2
L-1 1
udbhav 1
hpsounds 1
Zergon 1
Emalot 1
very angry mobster 1
bennybones 1
glitchpop 1
funky40 2
jberentsson 2
dubka 1



Last edited by moogah on Tue Apr 09, 2013 10:05 am, edited 13 times in total.
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Post by pre55ure »

Yes please ! :party:
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Post by nickster »

I would definitely be interested for one of these possibly two. In Euro for me, sir. Glad to hear Tom gave his blessing. Top :banana:

Hope all goes smoothly.
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Post by aladan »

Count me in for two. Thanks!

Edit: at $15 each, make that four :bacon:
Last edited by aladan on Thu Oct 11, 2012 3:54 pm, edited 2 times in total.
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Post by moogah »

nickster wrote:I would definitely be interested for one of these possibly two. In Euro for me, sir. Glad to hear Tom gave his blessing. Top :banana:

Hope all goes smoothly.
I'm happy to say that he didn't seem bothered by the request at all! Although I did specify that I was thinking of doing a maximum run of 100 and that these were for private use only.
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Post by Dego »

One please
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Post by raisinbag »

Sounds cool. I have lots of 3080's to Make use of. But would proaly just grab one pcb, as I'm saving up for a monster. :yay:
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Post by limpmeat »

i'd be in for 1
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Post by DannoGeeRay »

I'd be interested in 1 for euro.
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Post by ringstone »

:hail: Probably 4 Euro for me... nice work on getting permission from the man himself!

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Post by Barcode »

This is great! Put me down for 1 euro-style.
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Post by Joe. »

I'd want 4 PCBs, no panels.
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Post by carynrich »

i'll take 2 pcb's please.

will the LP/notch/HP have cv?
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Post by sinemod »

i woud like to hear more about the in and out but
i will certenly take 3 pcb will you offer Panel ?
i will be up for an eurorack version
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Post by marvkaye »

I'd be up for 2 PCBs as well.
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Post by wavehead »

At least 1 PCB.
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Post by theabsent »

Very likely. I love sem filter. You should make it both 12V & 15V compatible.
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Post by johnnymayer »

MAJOR interest in a euro format.

i think that oberheim filters, the SEM one in particular is absolutely big time phenomenal.
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Post by steffensen »

Im in for 1 PCB and 1 possible Panel? (euro format here too)
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Post by brother303 »

One here, please.

Peake wrote: DIY is all about the backlog. If you don't have a huge backlog, you aren't trying hard enough.
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Post by NV »

I'd be interested in 1 for euro format. If someone ends up doing a panel I may be in for more.
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Post by mouldi101 »

(Edited post - I just acquired a Doepfer SEM filter super cheap, so will have to remove myself from this list)
Last edited by mouldi101 on Mon Dec 03, 2012 2:54 pm, edited 1 time in total.
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Post by moogah »

This is great! We've definitely got enough interest for a run, I captured the schem last night and got the basic board layout done. What I'm working on now is getting the best possible footprints available for pots, power and other headers. The idea is to support board mounted pots with .100 or .200 spacing which also then supports standard PCB headers if somebody doesn't want board mounted pots. The board will definitely support both 12v with eurorack pot spacing AND 15v with MOTM pot spacing 8_) 8_)

Making the LP->Notch->HP voltage controllable is an interesting idea, I'm not working on that at the moment but let's not forget about it as the layout develops :) IIRC the blacet filthy filtre did this right? My only concerns are board space and the possibility that adding a pair of VCA's would affect the authenticity of the sound.

For those who want to get a head start, here are the non-typical parts you'll need:

2 CA3080
1 LM301
3 LM741
2 2N4302 N-Channel JFET

The 2N4302 are rather hard to find but smallbear has a part that supposedly works as a replacement for it. I'm going to have multiple footprints on the board for this part so builders can decide what they want to do. It's likely that a easier to find part like a J202 or 2N5487 will work just as well.

I've also found some sources for the 2N4302's but they're not cheap and there is always the risk of fakes so I don't think I could offer them for less than 5$ each.. which isn't so bad??

I'm not planning on offering a panel for this, not yet anyway. I don't have any experience with metalphoto or any of the tools used to make the nice looking panels we see so I think it's better to leave this up to someone else for now. I'll contact Ben at Re:Synthesis to see if he'd be interested.

Lastly, now that I've got the basic layout done it looks like the board will be a bit smaller than I had thought so it's very likely that each pcb will cost less than 20$. 15$ per board seems likely :) Maybe even a little less!
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Post by hv0190 »

2 PCBs for Euro, please! :yay:
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Post by keninverse »

Definitely interested in this. If Scott could do a bridechamber panel...that would be really sweet.
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