Wonderful_yusynth/steiner vcf on stripboard!!!

[MuBase]

For anyone interested in VCF design, I have been working on building a board for a weird sound generator Redux which is a bit of a Frankenstein's Monster of collected lfo's delays and this lovely Steiner VCF as adapted by the genius of SDIY/Yusynth: I have checked over the board layout and although really messy ( pot wires coming out at all angles etc...) It may work... I'll get back on that one in a couple of days when I have built it..The transistors used are 2n3904's. I would welcome any input on this one as I am not an advanced designer or anything...

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messy_yusynth_SB_design.png
Description:	Stripboarded version 1.0b
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VCF-2SC1583-sch.pdf
Description:	Original Sdiy design...	Download
Filename:	VCF-2SC1583-sch.pdf
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[MuBase]

With reference to the Yusynth steiner vcf stripboard layout in the layout factory: I built this after looking again and realise there are a few obvious mistakes ..( the 4.7k resistors coming from the 2.2 caps should be 47K. Pin 5 of the TL072 should be connected to ground and cv2 ear should go to a ground reference ( not the -15V connection!!!). Asides from that this thing has been driving me crazy. Can't get it to work. The -15V supply sinks all the way down to a few millivolts so there's a short somewhere but I don' know where. Please, can any experts on this great site point me in the right direction...??? I have looked over it 10 times and see no more faults..The soldering "looks" o.k. But to no avail...

[-minus-]

Hi! ...and sorry it's not working!

I'm always on the look out for stripboard layouts and noticed this. I haven't had much luck with filters in the past so excuse me if I have this wrong... I am just looking at the schematic and comparing it to your stripboard layout. Pin 6 of the TL071 and pin 6 of the TL072 are linked.

On the schematic, the path goes from pin 6 of the TL072 through a 10K resistor, then through a 10uF capacitor to pin 6 of the TL071. On your stripboard you have it going through the capacitor THEN the resistor. Maybe that should be swapped?

I'll stare at the schematic and layout some more and see if anything else jumps out at me... I am not an advanced designer or anything either

[MuBase]

Hi Minus! Thanks for the input. That's one thing i forgot to mention last time but thanks for pointing it out again. I have tried swapping the resistor/cap connections linking pins 6 and 6 of the op amps hoping this would fix it... alas!!!
i'll come back to it though...keep looking... it would be so nice to have a proper stripboarded version of this design ... cheers for now...
Steve.

[MuBase]

Can't for the life of me figure this one, anyways the circuit now sits silently in the green basket. ..I contacted a lovely guy in Australia called "Ken Stone" who sent me a board of his own design for a synthacon VCF. I have since assembled and is almost working exactly how i want it. Great stuff. My WSG redux is taking shape.........
Love to peeps everywhere.....

[-minus-]

Hello... I'm glad you have something working! I'll sit down and have a good look over your stripboard layout. I kind of forgot about it!

The Ken Stone stuff is nice! I've recently been breadboarding a lot of his circuits. In fact I have his Chime Simulator ringing away right now... as it has been for the past 9 hours! The CGS Drum Simulator is fun too!

If I spot something, I'll post my findings. I too have a box of failed circuits...

[-minus-]

I might have found something... unless you have already noticed it yourself.

D9 and D10 on the schematic are missing on your stripboard layout. These are the diodes between PIN 2 and 6 of the TL071.

If I see that you already have mentioned this, I'll edit this post...

[MuBase]

Hi Minus! Nice to hear from you again. I've taken into account what you said about the diodes missing. I remember I did actually leave them out as on the breadboarded prototype (pre stripboard) i noticed that by leaving them out it made the resonance a lot sharper ( which i like.. especially when using an VC to control the frequency...). seemed to work on the Breadboard but I think there's a problem with the grounds and that's why it's not working... i coud be wrong but....
any hoo, I've posted a page on the layout factory (see layout factory...Rog's post: "Suggestions for a first DIY project?" with a pic of the project thus far and a sample of what it can do...
Now i'm concerning myself with attaching all the 30 or so wires to various points for the patchbay...( oh what a joy.... : > ) )....