Yusynth Modules in Euro (12 Volt) Systems

[questionable]

For a number of reasons (mostly size and the availability of very interesting boutique modules), I have started a small Eurorack system. I am interested in doing some DIY work as well, and quite a few of the Yusynth modules are calling out to be included in the system.

While I have already found this thread about converting the moog filter to 12V:

http://www.electro-music.com/forum/topic-33887.html

...I'm curious:

1) Which Yusynth modules (if any) will work properly without modification in a 12V system?

2) What mods are required to get the rest working?

In particular, I'm looking at some of the bread & butter modulers (LFO, VCA, ADSR).

I really appreciate any assistance you all can give.

[yusynth]

Some can be used directly in 12V :

VCA, mixer, ADSR, most of the VCF, Gate delay, pulse delay, glide, Nois&SH, saw animator, logical, random gates, FFB, VC-LFO


Some can't and need important modifications :
VCO, CV-STANDARD

[questionable]

Thanks, Yves. It looks like I have some etching to do!

[questionable]

Is the Steiner Filter one of the VCF's that doesn't require mods for 12V?

[yusynth]

Yes

[questionable]

Perfect. It will be my first Yusynth project.

Thanks for making all of these projects available Yves. Very kind of you.

[turger]

If you don't mind answering another one, what about the vca-wavefolder? Can that be used within 12V configurations?

[yusynth]

[turger]

[TomHarding]

What modifications would need to be made to the Standards module so that it would work on a 12v supply?

[dstrength]

The problem is that the supply rails are used to generate the octave and semitone offset voltages. Thus, you'll need to recalculate resistors R3,R5,and R7.

After a quick check I would try to change R3=15K, and R5=130K, and R7=130K.

But, I'll warn you I'm guessing I'm missing something here. I don't understand why Yve's chose R5 as 180K and R7 as 156K in the original. It seems intuitive that these should match since they're generating equally opposite voltages.

I'm sure I'm missing something...as I can guarantee you that the odd value of 156K wasn't arrived at without due consideration.

[TomHarding]

Thanks

Probably a little out of my depth then. Thios dual voltage thing is a real pain.

I was looking at intergrating the three standards with 3 MFOS VCO's to give the VOC's, Octave, semitone and detune controls rather then the standard coarse and fine.

I can probaly get somthing to work with Rays ocatve switch circuit at;

http://www.musicfromouterspace.com/analogsynth/oddsandends.html

[yusynth]

Hi the values proposed by dstrength should do the trick.

For dstrength : To answer your question about the odd value of 156K , I first designed the circuit with symetrical values (i.e. 180K) for R5 and R7 but (probably because of the tolerance of some component or some impedance issue I haven't figured out) it was impossible to get the right range for the lowest values, then I simply trimmed the value of R7 until I got the right behaviour. If you have a clue to explain this misbehaviour of the 180K value I buy it.

[dstrength]

Thanks Yves. That makes sense. I simulated the voltage divider section in Multisim in order to see if I could figure out the discrepency. As you'd expect...under simulation you arrive at equal resistor values for the semitone offsets.

I think your explanation is the most logical: an aggregate of tolerance errors...most likely in the trimmers. Perhaps also differences in the absolute value of each voltage rail.

Thanks again,

Dave

[transistor logic]

i would like to know wich filters can be used with 12V without modification

[glitched]

I may as well ask, just to be sure: How about the ARP 7072 filter? Will everything operate as normal or will I have to pick up a few resistors?

[yusynth]

[hv0190]

I've just finished building the 4072 Filter and it's running perfectly in my 12V Eurorack system. Thanks a lot to Yves - you are the man

[yusynth]

Great news , no I know how to answer this question

[hv0190]

I know this is madness, but I had to squeeze both the 4072 and the Moog Filter into the 4HP Eurorack format:
By the way: It is really easy to achieve a good 1v/oct tracking with the Moog Filter. In self-oscillation you can play beautiful flute-like melodies.
And yes: it's running on +/-12V

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[yusynth]

Nice and colorful modules

[glitched]

Great job, hv0190! I can't wait to get my kit and my panel.

Let me ask you this: how did you mount the PCBs in 4HP? Would you mind taking a picture of the back?

Thanks!

[hv0190]

Thanks Glitched!
As you can imagine it isn't that easy when the panels are not even 1 inch wide, so I simply solder the pots (9mm Alpha) to perfboard and then fix the PCB on the perfboard.
I haven't got any pix of the filters, but this one here shows what I did to the T. Henry/Fonitronik X-4046 VCO ...
Maybe when I am more confident when it comes to working with aluminum I'll try and make some made-to-measure pot brackets

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[glitched]

Thanks so much for sharing that. I always panel-mount my pots when I do a layout on perfboard, but this time I'm getting a "real" pcb from bridechamber.com, which doesn't have spots for pots, on-board.

I don't have the tools to make brackets, so I was a little confused as to what to do! Anyway, yeah, I like your idea of mounting smaller pots on a perfboard, then mounting the PCB to that. I'll probably end up doing something like that. Thanks for the idea!

[hv0190]

OK, some update from the 12V/4HP loonie:
Some other YS modules running smoothly at 12V are the ADSR (I actually made an 8HP dual-version) and the Random Module.
Both are easy to build (thanks to Yves' excellent online documentation) and have worked 100% right from the start.
Yves, I cannot bow down often enough to praise your work