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[NEW] Serge Variable SLOPE Filter VCFS for Euro by R*S
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page 1, 2, 3, 4, 5, 6  Next [all]
Author [NEW] Serge Variable SLOPE Filter VCFS for Euro by R*S
nordlead
Happy to announce the release of the second Serge filter for Euro, the Variable Slope VCFS - under license and with the kind support from Serge.

The R*S version features 2 THAT2180 VCAs for best audio performance - Serge not only approved this, but recently stated that he would have used those VCAs if they had been available in the 70s.

Moreover, the Random*Source edition adds a Q knob, which allows to (substantially) increase the resonance, and has been optimized for an even wider range between minimum slope and maximum slope.




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Another demo (video) here: https://www.youtube.com/watch?v=HmYNxwNDJ2o

Currently the Euro version is available as a front panel (screen printed, 18hp) + pcbs kit. Module depth is < 40mm (~1.5").

See the R*S VCFS page for more info - that's also the order page.

Worldwide / international shipping as a signed Letter is € 9. Here's a picture of the kit contents:



Kits are shipping now w00t - as long as stock lasts.
Waldemar
Fantastic work Ralf we're not worthy
PWM
Nice! But stop emptying my bank account!
nordlead
Thanks, guys! Guinness ftw!

(It's a dilemma - I keep getting asked what's next and when it will be available...)
doomglue
What's next? When will it be available?
hyper

hihi
SkoPe
Missed the kit with unfancy parts waah

Hopefully it's back in stock soon or if someone can let me know a place where to get those Mica caps that would help a lot since I already have most parts (OPA's, That2180, 220pf styroflex)

BOM lists 2x OPA2134 and 3x TL072 or OPA2134 and I've noticed that you used 3x 2134 and 2x LF353, any special reason for that or just a matter of preference?

Also tayda it's out of stock of 250k B 9mm pots and Thonk doesn't seem to stock them.

As usual awesome work Ralf, thank you!
we're not worthy
ablearcher
at this rate I'm going to end up with a full euro serge system by summer This is fun! Dead Banana This is fun!
southphillysynths
ablearcher wrote:
at this rate I'm going to end up with a full euro serge system by summer This is fun! Dead Banana This is fun!


SlayerBadger! SlayerBadger! SlayerBadger!

me too! Like I don't need more of this stuff, but I will keep building anyway!
Isaiah
nordlead
Apologies if this seems off topic...
I'm curious how the VC-Slope function actually works.
Here's my guess:
The filter core is very similar to the VCFQ (minus the Trig In, AGC In, VC-Q and Notch Out).
The VC-Slope applies an offset to the second integrator in addition to the 1V/Oct and VC-F circuitry applied to both integrators.
The Q decreases as the integrators are driven further apart, like how an sharp image in a camera viewfinder becomes out of focus as you rotate the lense.
Does that sound correct?
akrylik
Isaiah wrote:
nordlead
Apologies if this seems off topic...
I'm curious how the VC-Slope function actually works.
Here's my guess:
The filter core is very similar to the VCFQ (minus the Trig In, AGC In, VC-Q and Notch Out).
The VC-Slope applies an offset to the second integrator in addition to the 1V/Oct and VC-F circuitry applied to both integrators.
The Q decreases as the integrators are driven further apart, like how an sharp image in a camera viewfinder becomes out of focus as you rotate the lense.
Does that sound correct?


I'm curious too. I was thinking it was just a cross-fade between a 1st order and a 3rd order filter but I haven't looked at the schematic and thus I suspect I'm very wrong.
Isaiah
akrylik
I don't believe there is a schematic available, that's why I'm guessing! hihi
listentoaheartbeat
Here's a Reichelt cart based on the VCFS BOM:

https://secure.reichelt.de/index.html?&ACTION=20&AWKID=1191681&PROVID= 2084

Notes:

- Does not include 2x THAT2180
- Does not include pots and jacks (go Thonk)
- Includes OPA2134 instead of TL072
- Includes bead instead of 10R resistors
- Includes precision strips instead of SIL headers (break to size)
- All resister values as per R*S recommendation
- Mica and Styro caps as per R*S recommendation
Waz
Just bought one!

Also, heads up. You listed this as 18hp in this thread. I'm pretty sure it's 14hp.
Waz
..
Waz
Here's the Mouser BOM I put together. I think it's complete.

BOM
Resistors - (DONE!)
Capacitors - Pretty sure everything is correct here. (Done!)
ICs - Everything accounted for. I used all OPA2134's in place of the TL072. I raises the price a bit. Is it worth it? I don't know. Add more 2n3904 if you would like to match your transistors.(Done!)
Misc. - You will need to source POTs, Jacks and Knobs elsewhere! Everything else is accounted for here. (DONE!)


I will update this as I get the information. Hopefully, this can help others and others can help me. Send me a PM if you find any issues.
DomMorley
Found some of the 250k linear pots: http://www.bitsbox.co.uk/index.php?main_page=product_info&cPath=94_325 &products_id=2280
Dogma
Ralf is there any way to ensure that DiYers actually have access to stock? i see the same dudes selling your modules over and over and they obviously bought a bunch to sell....dunno - i hope Random*Source is always stocked in the future because i feel a lot of excitement around these modules - theyre top quality. your easy going = success smile
listentoaheartbeat
Dogma wrote:
Ralf is there any way to ensure that DiYers actually have access to stock? i see the same dudes selling your modules over and over and they obviously bought a bunch to sell....dunno


These dudes ensure that non-DIYers can buy the modules at a reasonable price, which I think is only adding to the accessibility of The People's Synthesizer. No need to piss on anyone's parade. I am sure Ralf is here to stay.
listentoaheartbeat
DomMorley wrote:
Found some of the 250k linear pots: http://www.bitsbox.co.uk/index.php?main_page=product_info&cPath=94_325 &products_id=2280


Mainland alternatives:

http://www.musikding.de/Poti-9mm-250k-lin-Print-vertikal

http://uk-electronic.de/onlineshop/product_info.php?products_id=3274&o sCsid=c800b045738a4ff3e67dfd37eb72ec1a
Dogma
listentoaheartbeat wrote:
Dogma wrote:
Ralf is there any way to ensure that DiYers actually have access to stock? i see the same dudes selling your modules over and over and they obviously bought a bunch to sell....dunno


These dudes ensure that non-DIYers can buy the modules at a reasonable price, which I think is only adding to the accessibility of The People's Synthesizer. No need to piss on anyone's parade. I am sure Ralf is here to stay.


Yeah im sorry i worded that quite rudely - apologies to all...i just meant maybe if stocks are in short supply that maybe a limit could apply till fully stocked...
Waz
Waz wrote:
Here's the Mouser BOM I have so far. THIS IS NOT FINISHED.

BOM Red = Not finished. Green = Finished.
Resistors - (DONE!)
Capacitors - Need Micas AND I need someone to check my work here. Caps have always been my weakness. (Need help here)
ICs - Everything accounted for. I used all OPA2134's in place of the TL072. I raises the price a bit. Is it worth it? I don't know. Add more 2n3904 if you would like to match your transistors.(Done)
Misc. - Everything except the Jacks and POTS. (These will have to be sourced outside of Mouser) (DONE!)

I will update this as I get the information. Hopefully this can help others and others can help me. Send me a PM if you find other things.


This is like 90% complete. If any one could chime in on the troubled areas I'd be extremely grateful!
we're not worthy
listentoaheartbeat
Waz wrote:
Need OPA2134. Are these on Mouser? I am looking into getting 5 so all op amp chips are Burr-Brown (No TL072). I found a Texas Instruments chip with the same markings, but it didn't say Burr-Brown anywhere. Is this ok?[b]


Yes, TI and Burr-Brown merged in 2000! smile

http://www.mouser.com/ProductDetail/Texas-Instruments/OPA2134PA/?qs=sG AEpiMZZMtxdzBvM0rKca1NCdcAPFSCaGg8q6KvJG8=

Why 6x 2N3904? You just need three. Can look into the Mica caps later, ordered elsewhere but will give it a quick shot.
Dogma
Heres a good a place as any i guess - remember the Group Buy we had on the THAT 2180's and 300's? Anyone wanna do another? L1 has or is just about to release his VC res EQ and theres lotsa "candy" on there...we ended up getting them near half price from memory...
Waz
listentoaheartbeat wrote:
Waz wrote:
Need OPA2134. Are these on Mouser? I am looking into getting 5 so all op amp chips are Burr-Brown (No TL072). I found a Texas Instruments chip with the same markings, but it didn't say Burr-Brown anywhere. Is this ok?[b]


Yes, TI and Burr-Brown merged in 2000! smile

http://www.mouser.com/ProductDetail/Texas-Instruments/OPA2134PA/?qs=sG AEpiMZZMtxdzBvM0rKca1NCdcAPFSCaGg8q6KvJG8=

Why 6x 2N3904? You just need three. Can look into the Mica caps later, ordered elsewhere but will give it a quick shot.


Oops ill change it.
Waz
Oh wait.... I remember why 6.... Just in case anyone wanted to match their transistors.
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