[BUILD] stroh fadex plus, frac

[synthcube]

Build thread for the new stroh modular fadex plus for frac-rack

the panel/pcb set is available here:
http://synthcube.com/cart/index.php?rou ... uct_id=692

order your frac cabinets and power supplies from the original blacet research: www.blacet.com

[synthcube]

this is the placeholder post for the BOM, schematic, build guide and other documentation

[J3RK]

Update:

Build docs are now contained in the ZIP file in this thread:

https://www.muffwiggler.com/forum/viewt ... p?t=150552

This is due to Comcast killing off personal web space. I've also given the docs to Synthcube and Thonk just in case. If at some point I get more time on my hands again, I'll set up some hosting, and put these up properly again. I just wanted to make sure they were available again in the meantime.

[J3RK]

Now that things are moving again, I will get a wiring diagram together for this one first, as it's more complex than the others. I'll start it ASAP.

[synthcube]

we've completed the BOM development and kitting for this module. A few beta build kits have been sent out and we are encouraging those beta builders to post their progress, issues, comments here for everyone's benefit...

we're including both 3.5mm and banana jacks in the kits so you have your choice of jack style. We are kitting our black/dark red knobs, but the T18 pots are compatible with b/w Rogan knobs also if you prefer your frac panel monochrome rather than technicolor

https://synthcube.com/cart/stroh-modula ... ption=true

here's the current draft of the wiring:

[Rob_C]

Build thread for the new stroh modular fadex plus for frac-rack

Order your frac cabinets and power supplies from the original blacet research: www.blacet.com

Uh, FracRak cabinets and power supplies are also available from the "original" PAIA: www.PAIA.com

Link->PAIA FracRak case
Link->PAIA Regulated power supply

[werock]

Is there a functional description of this module anywhere? Obviously it's some kind of VCO, but a description of the 'fade' part would be useful.

[J3RK]

It's basically two parts.

One part is a VC Crossfader / Panner.

One part is a Triangle Core VCO (with sync, FM, etc.)

So you could do things like automate a crossfade of two signals using the included VCO, or you could use the cross fader to take the triangle and square waves from the VCO, and VC crossfade the shape (similar to a Buchla 258 or the like).

The oscillator has excellent Volt per Octave tracking, linear FM, full reset sync that you can hold indefinitely.

The AC/DC switch is for the coupling on the fader inputs. You could make some fairly complex modulations in LFO mode for example using DC coupling.

That's more or less the idea.

[werock]

Thanks for the explanation.

[diophantine]

One part is a Triangle Core VCO (with sync, FM, etc.

Aside from the fine-tune pot here, is this VCO the same as your PicoVCO?

[J3RK]

One part is a Triangle Core VCO (with sync, FM, etc.

Aside from the fine-tune pot here, is this VCO the same as your PicoVCO?

The main VCO board is nearly identical. The main difference is the shape of the PCB.

[fracmonkey]

But no documentation. Aside from the connection diagram, there seems to be nothing. Schematic would be helpful.

[J3RK]

But no documentation. Aside from the connection diagram, there seems to be nothing. Schematic would be helpful.

I believe I sent those to SC a while back. I'm happy to post them here as well, though I don't have them in front of me at the moment. (at work)

[fracmonkey]

The synth cube built docs have a link to THIS page!
Whose in charge? Sad.

[J3RK]

I'll attach them here.

[fracmonkey]

On the vco core pcb There is an eight pin smt pattern under q101/q102.

No ref des or any markings. Do we just ignore this?

[J3RK]

On the vco core pcb There is an eight pin smt pattern under q101/q102.

No ref des or any markings. Do we just ignore this?

You can use an SMT matched pair if you like, but you would then leave out the discrete PNPs above it. LS358 or SSM2220 will work there. (I use the LS358. They're excellent, log conformant, and half the price of the ADI parts.)

I apologize, I had an annotated version of the BOM. I will see if I can find that, or I will update the current one. There are no changes necessary, just additional notes about things like this.

One more note as this may come up. The caps labeled BP are just 100nF bypass and bulk caps.

[syncretism]

full reset sync that you can hold indefinitely.

Interesting - how does this work? Like, if I latched a voltage to its sync input, would it "stall" the oscillator? If so, that presents some interesting possibilities.

[soup]

if I latched a voltage to its sync input, would it "stall" the oscillator?

yes

[syncretism]

if I latched a voltage to its sync input, would it "stall" the oscillator?

yes

Nice.