[IN STOCK] Eurorack: Discrete State-Variable VCF v1.4

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james2098
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Post by james2098 » Mon Jan 04, 2016 8:55 pm

*SMT tip for new builders* (like me)
Sorry if this was said already, I missed it...

A. Follow Jason's SMT guide - it works surprisingly well for a SMT beginner!

B. START with the TL072 - Why?
Because I did the resistors & caps first and painted myself into a corner.
I'm sure if you have a better soldering iron you'd stand a better chance but I found it tight tacking down the pins 5,6,7,8 (right side).

Hope that helps at least someone :-)

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negativspace
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Post by negativspace » Mon Jan 04, 2016 8:58 pm

That's excellent advice and exactly how I do it. :tu:

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FingerTappin
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Post by FingerTappin » Wed Feb 03, 2016 10:58 am

Finally got this on the bench and tried out the retrofit. Seems to work well. I made a few noob blunders as this was my first stripboard project. Going back over it, and with some help from negativspace, I got it up and running.

Figured I would throw up a picture. Hopefully there are no errors, haha.

Image

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pulsepsycle
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Post by pulsepsycle » Sat Apr 09, 2016 10:42 pm

Sorry for cross posting but are the panels and pcb's still available? I would like one set. (posted in viewtopic.php?t=88663&highlight= earlier)

Best regards,
Karel.

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negativspace
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Post by negativspace » Mon Apr 11, 2016 4:19 pm

Nice work, FingerTappin! Missed the post while I was away in PR I guess. :oops:

pulsepsycle - yes, plenty in stock! PM me and let me know what you need.

Now, back to building the last of a batch of 15 of these things for Schneidersbuero for me...

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GryphonP3
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Post by GryphonP3 » Thu Apr 21, 2016 10:06 pm

Having some trouble figuring out what to use for

[2] 1nF Polystyrene/Polypropylene *main timing caps in VCF

I usually use Wima film caps when polyester is called for, but you specify polyester separate from he other film box caps, and it looks from the shots like there are some big silver caps there, and the lead spacing is pretty huge. Could you recommend some caps for use there, or give an example?

Cheers!
My cat can eat a whole watermelon ...

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gbiz
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Post by gbiz » Fri Apr 22, 2016 3:41 am

Depends on how you want the filter to sound, what you put in there will have a noticable effect on the sound. If you're happy unsoldering components, i'd suggest getting a couple of each type & trying them. You don't need to fully solder them in to test them.

Those big* silver caps are styrenes. They give the filter a nice smooth sound. If you use something like a Wima FKP2 polypropylene, it'll have a slightly more raspy/buzzy sound. I've always meant to give FKS2's or even some C0G's a try. I assume they'd be even more buzzy.

I've got four of these filters all fitted out differently, two with the original component spec where the filter doesn't quite self oscillate & two that self oscillate. One of each type has styrene & one with propylene. I can never decide which is my favourite sounding one, if i really had to pick one it'd probably be the one that doesn't self oscillate, with the FKP2's, but the styrene one really does sound lovely.

* Those styrenes don't have to be big. I used Suflex SC-225 from Rush online (linky). They're 7mm length, 3mm dia, so basically the same size as the Wima propylene.

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Shoggoth
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Post by Shoggoth » Fri Apr 22, 2016 7:42 pm

Small bear has the styrenes and I believe Jason has said he uses the pots from there as well. I did my build with these components and love it.

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synthcube
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Post by synthcube » Sun Apr 24, 2016 8:17 am

we're happy to report that we (finally) have full kits in stock for this awesome filter-- after a world-wide hunt for sources of the pots :lol:

this is one of the sharper-looking filters of its kind we have seen, and the changes that MA made to the circuit sound fantastic!

http://synthcube.com/cart/index.php?rou ... ct_id=1023
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TechnoPrisoner
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Post by TechnoPrisoner » Sat Apr 30, 2016 4:18 am

any chance we see the full kit in EU ?

thanks.

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mantiwhore
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Post by mantiwhore » Fri Aug 19, 2016 3:35 am

Image

Here's mine. Awesome module!
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WTB/T: Livewire Chaos Computer, Kilpatrick Dual VCO, Dewanatron Triple Slice, Nord A1R, Elektron SPS-1 UW+ II

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oootini
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Post by oootini » Fri Nov 04, 2016 3:29 pm

anyone have a SVVCF BOM in a sensible format? like a spreadsheet or something? :guinness: :guinness: :guinness:

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oootini
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Post by oootini » Fri Nov 04, 2016 3:52 pm

to save 30 min of someones life doing silly search and replace in text pad and csv, see attached for a mouser compatible BOM based on the pdf (why u no like xslx?) posted by synthcube.

rename the txt file as a csv and you should be good to go.

:guinness:
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mig27
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Post by mig27 » Fri Nov 18, 2016 5:03 am

Old post, I know.

But I had the same problem with my SVVCF.
My mistake was that I had installed a 1k SMD tempco on the rear AS WELL AS a 1k on position R44.
That's one too many.

Removing one of the two 1k's solved my problem..

Cheers


Michael
herringson wrote:Hey Jason,

I'm still having this weird problem where I can only get the frequency to sweep between 1 and 2 o'clock on the knob, either side I get no sound.

I've replaced U3, Q19, checked the resistors values and everything looks ok, I can't figure it out.

If I measure between R45 and pin 6 on the TL072 I get 0 volts for most the of the frequency knobs movement, it quickly sweeps from 0->6V between 1-2 o'clock and then for the rest of the knobs range is stuck at 6V.

I guess something is being amplified too much somewhere in the control voltage circuit and then clamping either side but I can't figure out where this is happening.

Is there a good place in the frequency control circuit where I could for a known good voltage and work back from there?

#stumped

Thanks.
Dylan.

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oootini
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Post by oootini » Wed Feb 22, 2017 6:34 am

hi, just about finished this build, i've not powered up/calibrated yet.

Anyone have any thoughts on the 10uF capacitors in the VCF section? do part selections here make a difference to the overall sound at all?

I have bog standard 10uF 25V electrolytics in there.

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303ish
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Post by 303ish » Sat Mar 18, 2017 4:52 pm

I finished my build some days ago but unfortunately it doesn't work as expected. Then I found that the BOM and photos in the first post have different resistor values (and who knows what else). I spend my afternoon debugging and already got almost everything working, except for the v/oct tunning. When I increase the resonance to the max there is a pulsating distorted signal that comes and goes.

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oootini
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Post by oootini » Sun Mar 19, 2017 4:32 am

303ish wrote:I finished my build some days ago but unfortunately it doesn't work as expected. Then I found that the BOM and photos in the first post have different resistor values (and who knows what else). I spend my afternoon debugging and already got almost everything working, except for the v/oct tunning. When I increase the resonance to the max there is a pulsating distorted signal that comes and goes.

Yeah I have the exact same issue. Built board 1.4. What values from the first post are incorrect?

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303ish
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Post by 303ish » Wed Mar 29, 2017 3:26 pm

oootini wrote: Yeah I have the exact same issue. Built board 1.4. What values from the first post are incorrect?
I emailed negativspace and he confirmed the BOM values, they are ok. I was just a bit confused with all the discussion on this thread.

That said, the resonance still was too much distorted to me. With 330K on R13 I have a lot more control - increasing the signal drops the resonance level.

itsritual
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Post by itsritual » Mon May 01, 2017 10:01 am

My frequency range is only really effective past 12 O'clock. On lowpass, it's basically muted for the first half going clockwise, then the filter only starts opening up in the second half. Any one else with this issue?

fwiw my main board is v1.4, control board is v1.3

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Post by itsritual » Wed May 03, 2017 1:51 pm

After rereading the entire thread looks like there's a few people with similar, but no solution posted.
sromanel wrote:After installing a brand new SMT TL072 and redoing a few joints, the problem is still there (ie no change in sound from cutoff fully CCW to 12:00, weak outputs, all filter types behave like a different flavor of LP). I'll attach photos of my PCBs asap. Any help would be reeeeeeally appreciated
qfactor wrote: Mine's got all weird on me!! :sadbanana:
I did the new values expecting things to be more balanced, but instead, after changing to the new resistor values (stated in your list) the cutoff now only works from 12 o'clock onwards. Closes up way too much and too fast from the left half (CCW) of the cutoff knob! :eek:

Also, now, the resonance doesn't self oscillate, with the new values. The old values did all that better but I can't tell if it's more balanced with these changes now :doh:

Which are the resistors that controls cutoff and resonance in your list? :hmm:
herringson wrote:I build my one of the three @JackMattson got yesterday.
All working and sounds amazing!

The only problem I'm having is the cutoff frequency control has a very limited useful range, somewhere between 1-2 o'clock sweeps frequency, everywhere else is dead range.

The CV inputs are also overly sensitive and barely opening up the CV pot causes massive sweeps.

I've tried trimming the V/oct but that didn't help.
Does the 1.4 PCB have the correct LM337 orientation?
Anyone have other ideas about obvious things I could have done wrong?

I didn't see where I could find a schematic to try and troubleshoot, if there's a link please let me know.
Thanks!
Pretty sure there were others, but couldn't find them again.

Any clues? Went over the board, and paid special attention to the CV section on the upper right, but found nothing.

oskary
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Post by oskary » Fri Oct 13, 2017 1:23 pm

Happy builder of a SVVCF here, though I kind of expected slightly better tracking of the filter. I get at best one octave with my build.

There is some info about using a tempco for R44 in this thread, but this is not documented in the BOM on the first page - it looks like it does not apply for the version 1.4 PCB?

So, my question is:

- Can I still replace R44 with an 1k tempco, either through-hole or SMT?
- What specs should I choose for a tempco?

Hope somebody can help! :help:

zorglub76
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Post by zorglub76 » Sun Feb 04, 2018 8:23 am

Just to make sure: are these Erthenvar jacks (PJ301BM), and do they go on PCB like this (without any modifications)
Image

jimfowler
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Post by jimfowler » Sun Apr 08, 2018 8:59 am

Did the limited frequency knob control range (and very sensitive cv inputs) ever get addressed? Filter sounds great but kinda not useful in its current state.

My frequency knob doesn't do much from full ccw to ~10 and then stops effecting around 3-4 o'clock to fully cw. As well, as I'm sweeping it the frequency knob it mutes the output momentarily...like it's muting the output while it figures out where the frequency range knob is now set.

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Jumbuktu
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Post by Jumbuktu » Thu May 24, 2018 5:23 am

I seem to have stuffed up my build. On power up, no other modules in the case come on. Fuse is not blown - remove svvcf and everything is Ok. Case is doepfer LC6U. Any ideas where to start?

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khakifridge
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Post by khakifridge » Thu May 24, 2018 7:25 am

Get your DMM out and check for shorts between the power rails and 0V.

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