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[pcb+panel] CEM3340 VCO for eurorack (8hp)
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page 1, 2, 3  Next [all]
Author [pcb+panel] CEM3340 VCO for eurorack (8hp)
TimoRozendal
Hi All,

I have made a small vanilla implementation of the cem3340 vco for eurorack in 8 hp. It has the basic waveforms and 3 simultaneous sync options.
It is a nice stable analog vco with good tracking.


(Yes, Nonlinear Circuits also has a vco based on this chip, but that one is bigger and with some extra's that my version does not feature. (They are not related as far as I know, mine was kinda done when I first heard about his). I think they can coexist.)


Here are a few pics:


(ps: the bottom 2 pics are of a prototype, hence, the wooden panel and different knos)


Here are a few instagram demo vids:
- soft sync demo https://www.instagram.com/p/BJ0zvAWhlVc/?taken-by=timorozendal
- saw + steiner parker https://www.instagram.com/p/BJ001jyh575/?taken-by=timorozendal
- acid line with benjolin filter https://www.instagram.com/p/BKERaKrhKRv/?taken-by=timorozendal
- bass line in context with eurorack drums https://www.instagram.com/p/BKJbiU1hK-L/?taken-by=timorozendal

build info/code:
it is SMD and mostly 0805 (the smallest part being the voltage regulator, sot23-5) but not that hard.
Don't worry about all those multiturn trimmers, calibration is easier than you think. There are no special other components apart from a good quality 1.5nf capacitor and I think you need to order the voltage regulator at a place like mouser.
The chip can be bought via OnChip (email: susanonchip@covad.net) or shall I buy a bunch and ship it with the pcbs?

link to online BOM / build doc (including schematic)

availability/pricing:
pcb: 10 euro
panel: 10 euro
chip: 22 euro
shipping: 3e for panel, 4 for pcb+panel, other quantities need to be weighed first
I have 12 pcb sets now available and 10 chips , will order more afterwards if necessary

order list
altitude909 3x pcb [shipped]
skee 2x (pcb+panel) [shipped]
niicholas pcb+panel+chip [shipped]
humax5600 pcb+panel+chip[shipped]
grizzle: pcb+panel+chip [shipped]
windspirit 2x (pcb+chip) [shipped]
LED-man pcb+panel+chip [shipped]
jjsynth pcb+panel [shipped]
oberkorn pcb+panel+chip [shipped]
batank pcb+panel+chip [shipped]
PWM pcb+panel [shipped]
Check Mate pcb+panel+chip [shipped]
daryll pcb+chip [shipped]
andrewF
TimoRozendal wrote:



(Yes, Nonlinear Circuits also has a vco based on this chip, but that one is bigger and with some extra's that my version does not feature. (They are not related as far as I know, mine was kinda done when I first heard about his). I think they can coexist.)



Of course they can co-exist Chugging Beers Drinking
I expected there would be a dozen different 3340VCO designs out by now. Such a good chip w00t
TimoRozendal
andrewF wrote:

Of course they can co-exist Chugging Beers Drinking


nanners
The_Crooked_Man
I'd personally rather have a sine wave output in lieu of one of the 3 kinds of sync. Other than that, looks perfect thumbs up
humax5600
@ Timo
I am interested in 1x Panel and 1x PCB.
And if possible 1x CEM 3340 to it.
skee
I would take two panels and two boards, please.
sleepgardens
Do you think it would be suitable as a first SMD project? I have some MI boards but I'm hesitant. Maybe starting with something bigger is better?
J3RK
The_Crooked_Man wrote:
I'd personally rather have a sine wave output in lieu of one of the 3 kinds of sync. Other than that, looks perfect thumbs up


The dual-NPN style of triangle to sine converter would be absolutely tiny, and quite trivial to place on a tiny sub-PCB that would only have 3 power connections and 2 signal connections.

The panel would be the only somewhat tricky part. Or just output the sine through the triangle jack if you preferred that.
niicholas
Looks sharp-

I would like one set: PCB and Panel
And would spring for one CEM3340 if you decide to ship those as well.

thanks
falafelbiels
Really nice!
Jarno
Leuk ding Timo!
TimoRozendal
All orders are updated. And I have just ordered 10 cem chips (not sure about the price yet, due to currently unknown import and shipping duties)


The_Crooked_Man wrote:
I'd personally rather have a sine wave output in lieu of one of the 3 kinds of sync. Other than that, looks perfect thumbs up


sorry, I voted for the sync options... :-)
perhaps a standalone tri to sine shaper is interesting?

sleepgardens wrote:
Do you think it would be suitable as a first SMD project? I have some MI boards but I'm hesitant. Maybe starting with something bigger is better?


tough question, I don't think this is very hard, it is simpler than MI, but still, maybe start with something slightly simpler like this:
https://www.thonk.co.uk/shop/music-thing-modular-simple-eq-full-kit/
oberkorn
Hello Timo I'll take one pcb/panel set (and chip if you have enough stock).
shipping to Sweden, you can post it with the FM ogre
n167tx
Bump for timo SlayerBadger!
TimoRozendal
update:
- status info added for all orders
- added link to online BOM/build doc
grizzle
I'm in for a pcb, panel and chip if you decide to buy some and ship them with PCBs and panels.
TimoRozendal
grizzle wrote:
I'm in for a pcb, panel and chip if you decide to buy some and ship them with PCBs and panels.


that's fine, I bought some... :-)
skee
Hi Timo. Can you post the circuit with the pcb's please? I 'may' want to make some mods hihi
LED-man
Please one pcb,panel,chip
jjsynth
hi timo
one pcb and one panel for me please. Thanks.
TimoRozendal
skee wrote:
Hi Timo. Can you post the circuit with the pcb's please? I 'may' want to make some mods hihi


I will add it to the build info, just need some time to clean it up and put it all together
TimoRozendal
the cem3340 chips are in!
everybody on the list has received payment requests (let me know if I forgot something)
this first batch of pcbs has sold out, but there are new ones on the way
batank
Sign me up for the wait list (pcb, panel, chip)

Kind thanks!
PWM
I'd be in for a PCB/Panel. Like the look of the panel!
Check Mate
Hi Timo,

Please put me down for 1x PCB + Panel + Chip.
Thanks!
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