1J17B Tube VCF eurorack

From circuitbending to homebrew stompboxes & synths, keep the DIY spirit alive!

Moderators: luketeaford, Joe., lisa, Kent

User avatar
Synthsense
Common Wiggler
Posts: 217
Joined: Sun Nov 04, 2012 12:40 pm
Location: VCAlona

Post by Synthsense » Sat Aug 05, 2017 4:59 am

Sounds good to my ears! :tu:
Last night I lay in bed looking up at the stars in the sky and I thought to myself, Where the heck is the ceiling? :hmm:

User avatar
maltemark
Ultra Wiggler
Posts: 758
Joined: Tue Dec 16, 2014 11:39 am
Location: Gothenburg

Post by maltemark » Sat Aug 05, 2017 10:47 am

Super cool

rvrv
Learning to Wiggle
Posts: 31
Joined: Wed Aug 24, 2016 2:24 pm
Location: france

Post by rvrv » Tue Aug 29, 2017 4:03 am

I have added a VCA instead of a fix gain for the tube. Much more fun.

short video with phone audio :


Next step is adding cv for the resonance and I think that will be enough for the functionalities !

widgetoz
Veteran Wiggler
Posts: 694
Joined: Sat May 02, 2009 1:32 am
Location: Sydney, Australia
Contact:

Re: 1J17B Tube VCF eurorack

Post by widgetoz » Tue Aug 29, 2017 4:41 am

rvrv wrote:Hi,
So I have hear this :

https://www.youtube.com/watch?v=KhRn9sN ... ture=share

the author said it was built from this schematics
http://www.homebuilthardware.com/index.php/projects/sk-tubevcf/

using 1J17B tubes.

Is there someone interested to help me porting this schematics to eurorack +12/-12v?
Have you looked at the CGS65 from Ken Stone? Circuit looks very similar.
I also have it as 12V module in the CGS765

rvrv
Learning to Wiggle
Posts: 31
Joined: Wed Aug 24, 2016 2:24 pm
Location: france

Post by rvrv » Tue Aug 29, 2017 4:53 am

thanks. I have looked at the CGS65 yes and the sk vcf design by Ryan williams is inspired from it. The vca control I have tested is from the befaco tube vca.

User avatar
evengravy
Common Wiggler
Posts: 83
Joined: Tue Aug 13, 2013 4:31 pm
Contact:

Small world

Post by evengravy » Sun Sep 03, 2017 6:59 am

Hey,

It's John. I was talking to you, rvrv, via youtube yesterday. Our company (deltasoundlabs) are releasing this filter as a commercial unit with permission from the author within the next month or so. We've kept pretty much to the original schematics and made some adjustments here and there for eurorack voltages. Everything is squeezed into 8HP and on one skiff friendly pcb.

I really love what you are doing with the CV controlled resonance and VCA too. Great idea!

Here's a pic of the front of the PCB so you can get an idea of our dev so far:

Image

All SMD on the rear side

rvrv
Learning to Wiggle
Posts: 31
Joined: Wed Aug 24, 2016 2:24 pm
Location: france

Post by rvrv » Fri Apr 20, 2018 3:20 am

Hi all, if there are still people following this post.

I have some good news, I made a first 14hp version of the board. VCA + LPF. I have dropped trying to add a resonance control for now.

Image

Not really usable yet but the cutoff sweep is still very very nice. In the process I have learned kicad and its very satisfying. I have identified some problem in the first version, most are easy to fix. The pots are too close at the bottom for example. Also some of them are reversed. :doh:

The next revision should be better so in the coming month I will search some beta testers !
[/img]

Jarno
Super Deluxe Wiggler
Posts: 2772
Joined: Mon Nov 15, 2010 6:34 am
Location: Rosmalen, NL

Post by Jarno » Fri Apr 20, 2018 5:21 am

Nice! So this has another tube at the back?

rvrv
Learning to Wiggle
Posts: 31
Joined: Wed Aug 24, 2016 2:24 pm
Location: france

Post by rvrv » Fri Apr 20, 2018 7:20 am

Jarno wrote:Nice! So this has another tube at the back?
No just the one on the front, not sure I will keep it there in the next layout though.

Jarno
Super Deluxe Wiggler
Posts: 2772
Joined: Mon Nov 15, 2010 6:34 am
Location: Rosmalen, NL

Post by Jarno » Fri Apr 20, 2018 7:43 am

Sorry for not reading everything, but so this is either VCA or LPF not LPF followed by VCA?

rvrv
Learning to Wiggle
Posts: 31
Joined: Wed Aug 24, 2016 2:24 pm
Location: france

Post by rvrv » Fri Apr 20, 2018 7:48 am

Jarno wrote:Sorry for not reading everything, but so this is either VCA or LPF not LPF followed by VCA?
No prob, it will be LPF first then VCA.

User avatar
Laszlo
Learning to Wiggle
Posts: 3
Joined: Tue Oct 06, 2015 2:56 pm
Location: Malmö, Sweden

Post by Laszlo » Mon Aug 27, 2018 7:22 pm

I really want to build this! Any updates on a pcb-run?

rvrv
Learning to Wiggle
Posts: 31
Joined: Wed Aug 24, 2016 2:24 pm
Location: france

Post by rvrv » Tue Aug 28, 2018 8:54 am

Hello, next design version of the pcb is on its way. I think I will re-check it end send to fab in september. So you can expect an update beginning of october.

User avatar
Eric the Red
Veteran Wiggler
Posts: 741
Joined: Tue Jun 02, 2015 12:43 pm
Location: Detroit, MI

Post by Eric the Red » Tue Aug 28, 2018 9:14 am

Sounds good. I’ll be down for 2-of these
Abandon all hope, ye who wiggle.

User avatar
Laszlo
Learning to Wiggle
Posts: 3
Joined: Tue Oct 06, 2015 2:56 pm
Location: Malmö, Sweden

Post by Laszlo » Tue Aug 28, 2018 3:26 pm

That's great news, rvrv! Count me in for two also.

IImyment
Learning to Wiggle
Posts: 31
Joined: Wed Nov 13, 2013 5:12 am

Post by IImyment » Mon Oct 01, 2018 10:23 am

:yay: still up for it

rvrv
Learning to Wiggle
Posts: 31
Joined: Wed Aug 24, 2016 2:24 pm
Location: france

Post by rvrv » Tue Dec 04, 2018 6:46 pm

Hello !
I have achieved a big step and I can provide some pcb for testers.

The 12HP design is :

Input-1 --> attenuator 1
Input-2 --> attenuvertor 2. If nothing is plugged in Input-2, the output is fed in attenuvertor 2 for feedback control.

Mix of output of attenuator 1 + attenuvertor 2 goes to the VCF

VCF has two control Freq CV + Freq Pot. A switch can choose between low pass and High pass by changing the vactrol wiring. Note that with the second attenuverter providing feedback the output may have two resonant peaks at different frequencies . This can lead to cool or strange results !

VCF output is Fed to the tube wich act has VCA.
VCA has two control Gain CV and Gain Pot. Audio can be fed in the Gain CV for more fun.
Tube bias can be choose between "hot and cold" by changing the voltage applied to pin 4 and 6, this can also be adjusted to taste by changing the resistors value for this two positions. This is the same mod suggested by primate synthesis on the ken stone design of the CG65.

Resonance control is changed by... the Res Pot. I had no time to find a CV control.

When adding feedback + resonance, the output may produce some nice chirp sounds. Hence the "Cigale" design (cicada). For some it will be annoying, personnaly I love it.

To keep this module small the resistors are soldered vertically on the back. This is not very elegant but in any case, a protective panel could be added...

I am looking for testers and can provide PCB + Panels. Design of the panel may change a bit because it's not perfectly readable on the first version.
Also I will provide the updated schematics in the coming days.

Name your price for this first run of PCB, with or without aluminium panel + count between 4 and 7 euros for shipping worldwide from France, depending on the destination. I can also provide fully built modules if someone is interested.

I already count 2 for Laszio, 2 for Eric the Red, one for IImyment?

Note that I have tested the schematics with 1J17B tubes but it will sure work with 1J24B by adapating a few resistors value.

Image
photo with the aluminium panel.

see here part 3 for a very quick video example. The module is not well calibrated but it provides a good idea of the result.

IImyment
Learning to Wiggle
Posts: 31
Joined: Wed Nov 13, 2013 5:12 am

Post by IImyment » Wed Dec 05, 2018 4:30 am

:yay: I am still really interested.

User avatar
synthetek
Wiggling with Experience
Posts: 474
Joined: Fri Jun 05, 2015 3:32 am
Location: Orange County, California
Contact:

Post by synthetek » Wed Dec 05, 2018 5:36 am

I am interested in a set pcb/panel. I have the vactrol and probably most of the parts , except the tube.

User avatar
Eric the Red
Veteran Wiggler
Posts: 741
Joined: Tue Jun 02, 2015 12:43 pm
Location: Detroit, MI

Post by Eric the Red » Wed Dec 05, 2018 12:52 pm

I have been waiting [impatiently] for this anncement! I am still in for those 2 sets, no panel for me.

I plan on building both of these into some ridiculous Vocoder I have on the build list. This thing is so donkey brained...

Where should I PayPal the funds to for this?

-Eric
Abandon all hope, ye who wiggle.

User avatar
Fernando
Common Wiggler
Posts: 69
Joined: Mon Nov 07, 2016 11:58 am
Location: Barcelona & Emporda, Spain

Post by Fernando » Wed Dec 05, 2018 12:54 pm

It would be good to see a diagram to understand what did you implemented in your version
.

Fer

rvrv
Learning to Wiggle
Posts: 31
Joined: Wed Aug 24, 2016 2:24 pm
Location: france

Post by rvrv » Wed Dec 05, 2018 2:57 pm

Eric the Red wrote:I have been waiting [impatiently] for this anncement! I am still in for those 2 sets, no panel for me.

I plan on building both of these into some ridiculous Vocoder I have on the build list. This thing is so donkey brained...

Where should I PayPal the funds to for this?

-Eric
Nice ! I contact you via pm.
Fernando wrote: It would be good to see a diagram to understand what did you implemented in your version
Of course, I will upload the schematics tomorrow.

rvrv
Learning to Wiggle
Posts: 31
Joined: Wed Aug 24, 2016 2:24 pm
Location: france

Post by rvrv » Wed Dec 05, 2018 5:16 pm

Here is the schematic for version 0-3 : Tube VCF_0-3.pdf

Any feedback are much welcomed.

User avatar
Fernando
Common Wiggler
Posts: 69
Joined: Mon Nov 07, 2016 11:58 am
Location: Barcelona & Emporda, Spain

Post by Fernando » Wed Dec 05, 2018 6:11 pm

I meant a block diagram, but great to see the complete schematic. Comparing it with the original (IIRC, an LPG followed with a version of Ken's CGS65 tube VCA) one can find out what was added or modified and see the functional blocks.

Much more clear now with the schematic, thank you!
.

Fer

User avatar
oberkorn
Veteran Wiggler
Posts: 609
Joined: Tue Jan 18, 2011 6:30 am
Location: in the EU

Post by oberkorn » Wed Dec 05, 2018 6:35 pm

I'm in for one pcb/panel set thanks, shipping to Sweden

Post Reply

Return to “Music Tech DIY”