New Frac Items...

Blacet, Metalbox, Synthasonic, PAiA and the rest.... a frac frenzy!

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fluxmonkey
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Post by fluxmonkey » Tue Mar 31, 2015 7:41 am

if panels are made i hope they have 1/4" holes for jacks... much easier to enlarge them for bananas than shrink them for 3.5mm...
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Post by BananaPlug » Tue Mar 31, 2015 8:10 am

Any time you want to put minis in an oversized hole you have a couple choices. If the difference is not huge a good trick is to get a bag of the tiny rubber bands used by orthodontists. Use them like o rings on the mini. They center the jack in the hole and squish down out of the way, unlike shoulder washers which add thickness.

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Post by J3RK » Tue Mar 31, 2015 10:15 am

fluxmonkey wrote:if panels are made i hope they have 1/4" holes for jacks... much easier to enlarge them for bananas than shrink them for 3.5mm...
Actually, the holes are .328" which is both a usable size for bananas, and this type of 3.5mm jack:

http://synthcube.com/cart/index.php?rou ... uct_id=152

This seemed to be a good way to get the panels to work with both jack styles.
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Post by monstrinho » Tue Mar 31, 2015 11:06 am

J3RK wrote:
fluxmonkey wrote:if panels are made i hope they have 1/4" holes for jacks... much easier to enlarge them for bananas than shrink them for 3.5mm...
Actually, the holes are .328" which is both a usable size for bananas, and this type of 3.5mm jack:

http://synthcube.com/cart/index.php?rou ... uct_id=152

This seemed to be a good way to get the panels to work with both jack styles.
I've built a couple of the other Synthcube frac kits with the holes sized this way. I tested them with both bananas and mini jacks and they work fine either way with no problems at all. :sb:

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Post by Isaiah » Tue Mar 31, 2015 6:52 pm

J3RK
Dustin, these are looking great!

A few questions about the VCF:
*Does it track 1V/Oct accurately and is it temperature compensated (or can a Tempco be installed)?
*Does the it only self-oscillate with an feedback loop patched?
*What is the frequency range of the oscillation and how stable is it?
*Is the circuit on one PCB, or spread across two?

I was thinking about all the different ways one could wire these PCBs to build a complex dual VCO.
I thought it might be an interesting variation to use a VCF instead of the modulation VCO.
One could mix between LP and BP outputs of the self-oscillating or pinged VCF to get a waveform other than a sine.
I might be wrong, but I think the Ping input could be used as a sort of Sync input.
The Resonance setting would dictate the decay time for FM of the VCO by the pinged VCF.
The VCO could have one of the VC-Fade PCBs for Buchla 258-like action, or just as a VCA for AM.

Just some thoughts I had today.
What do you think? Am I overlooking anything?

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Post by J3RK » Wed Apr 01, 2015 11:25 am

This is all on a single 3x3 PCB. (same size and shape as the VCO core, Shaper, ADSR, etc.)

It is V/Oct, with tempco. Depending on how it's trimmed it will oscillate. I've gotten varying results on the range of oscillation depending on the type of caps I use. The range was much wider (no additional patching) when using film caps (as mentioned by Dr. SnE in another thread.) When using MLCCs it doesn't oscillate as easily, or as wide of a range. However the resonance has a more bubbly/mellow sound to it. So this part is really going to be up to anyone building it.

The ping circuit is just an RC network, set up similar to a gate to trigger converter. It's not a schmitt trigger like the Serge version. I didn't want to steal from that design. This works great for doing little ping sounds and such, but I don't think it would work as a sync in oscillation. It would just pulse it, not reset it.

I personally would still use two VCOs in a complex VCO scenario, but that's definitely an interesting idea to use the VCF. Since the outputs are all in phase, I'm not sure you'd get a dramatic difference in timbre by mixing them. (I'd have to try this to be sure though.)

Anyway cool idea. I think you might get more variety having two VCOs though with the additional waveforms available. Also, even though the VCF is V/Oct with tempco, it's not going to track as well as the VCOs do. As far as the 258-like idea, the Frac version of the FadeX includes a VCO core, and does exactly that. (not to mention being used in reverse as a modulator for panning/fading.)

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Post by Isaiah » Wed Apr 01, 2015 2:19 pm

Thanks for all the information.

Hmmm... Yes, I fear you're right!
Seems that it might be more interesting on paper than useful or predictable in reality.
Just to clarify, I thought the VCF outputs would be 90 degrees out of phase, is that not the case? You could mix the LP and BP outputs to get something other than a sine, right?

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Post by KNYST » Fri Apr 03, 2015 7:09 pm

Beautiful work! :guinness:
J3RK wrote: :party:

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Post by J3RK » Tue Apr 07, 2015 10:31 am

Thanks!

I just finished up a couple more panel layouts, and the first 7 prototype PCBs will be here next week. The circuits are already tested and used in other PCB layouts, but I thought one more test pass on the new sizes/shapes was a good idea. It looks like the panels for the first 4 modules will be a 5 week turnaround, so PCBs/Panels should be available around then, followed by kits, and then some complete modules after that. I'll post more information on those as this all happens as I'm sure Synthcube will as well.

I should have the demo system above functional in about two weeks, and can start posting some sounds and maybe a few quick videos.

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Post by Isaiah » Thu Apr 09, 2015 4:53 am

J3RK
Sorry, more questions!
Hopefully this is an appropriate place to ask.

•Do your Frac-format PCBs have headers for power distribution between stacked PCBs, or does each require a Frac PSU connection?
E.g. The FadeX Plus: are both PCBs connected to the PSU/busboard, or just one with internal power distribution to the second PCB?

•Is there a Sine wave output available from any of the Frac-format VCOs?

•With the CGS-format UFO, does the variable wave fade from Sine to Saw/Pulse with increasing positive voltage (like the Buchla 258) or negative voltage?
Is a full +/-5V CV input required (ignoring the manual offset) to fade from Sine to Saw/Pulse completely?

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Post by J3RK » Thu Apr 09, 2015 10:00 am

The PCBs have combination MTA-156 (MOTM/Frac) and DIL-10 (Euro) headers like on the 4U boards. So you could run wires or pins between the DIL-10 headers, then run a single MTA-156 connector for module power. This is what I typically do with stacked boards.

If it was a case like the BitBucket with a ton of switching CMOS, it might be better to give that PCB a separate run to the PSU than the VCO board. Not necessary, but it could have a small advantage I would think.

Due to the size and shape of all of these PCBs, they will also lend themselves easily to other formats. For example, if you liked the functionality of one of these Frac versions more than one of the existing 4U boards, you could stack them length-wise instead of layered, and the mounting holes would be in the same positions as the 4U counterpart.

Sine wave is available on the UltraPulse, and the Dual VCO. The panels in the pictures and layout drawings are a little different than the ones that will be available. The blue panels above are for my own test system. The drawings on the first page of the thread are now slightly out of date. The final panels will be on the Synthcube site fairly soon. To be clear, the panels are laid out the same way as in the pics overall, using the same finishes and techniques, I've just added or moved a function or two here or there, some based on suggestions, others based on my test panels.

As far as CVs go, I use two standards. I use bipolar -5 to +5 CVs for anything that's a balanced behavior like panning, crossfading, etc. For things like envelopes, sequencers, etc. I use unipolar 0 - 10 CVs. The CVs will always be a 10V range though. The CV processor module has three "attenuverting" inputs, plus a 5V reference voltage that can be patched in to shift a bipolar signal all the way above or below DC, so you can pretty much shift them to wherever you want them. Furthermore, all logic and clocked inputs have comparators and can be triggered from anything over around 1.5V.
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Post by J3RK » Wed Apr 15, 2015 1:12 am

Few more panels done, and test PCBs arrive tomorrow. :party: :hyper:

Edit: Boards are in! I think I might be able to have 2-3 modules functioning tonight. :party:

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Post by reignbear » Thu Apr 16, 2015 7:48 pm

J3RK wrote:Few more panels done, and test PCBs arrive tomorrow. :party: :hyper:

Edit: Boards are in! I think I might be able to have 2-3 modules functioning tonight. :party:

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Post by BugBrand » Fri Apr 17, 2015 3:37 am

Lots & lots of super lovely!

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Post by fluxmonkey » Fri Apr 17, 2015 8:19 am

J3RK wrote:
fluxmonkey wrote:if panels are made i hope they have 1/4" holes for jacks... much easier to enlarge them for bananas than shrink them for 3.5mm...
Actually, the holes are .328" which is both a usable size for bananas, and this type of 3.5mm jack:

http://synthcube.com/cart/index.php?rou ... uct_id=152

This seemed to be a good way to get the panels to work with both jack styles.
sure, but i'd rather not be locked in to having to use those, or the o-ring hack. but that's just me, and i can always make my own panels... all good.

b
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Post by Cat-A-Tonic » Fri Apr 17, 2015 8:48 am

fluxmonkey wrote:
J3RK wrote:
fluxmonkey wrote:if panels are made i hope they have 1/4" holes for jacks... much easier to enlarge them for bananas than shrink them for 3.5mm...
Actually, the holes are .328" which is both a usable size for bananas, and this type of 3.5mm jack:

http://synthcube.com/cart/index.php?rou ... uct_id=152

This seemed to be a good way to get the panels to work with both jack styles.
sure, but i'd rather not be locked in to having to use those, or the o-ring hack. but that's just me, and i can always make my own panels... all good.

b
If it makes any difference, those particular 3.5mm jacks are pretty nice compared to a lot of other ones.

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Post by werock » Fri Apr 17, 2015 9:22 am

I've got those jacks on a Synthcube module and they seem fine to me. My only issue with them is the knurled nuts, not sure what tool to use to tighten them properly. I'd prefer hex nuts, but it's a minor quibble.

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Post by J3RK » Fri Apr 17, 2015 12:15 pm

Thanks for the kind words!

Yes, I think if those jacks had hex-nuts they'd be perfect for 3.5mm. As they are, I still like them. I'm happy to help with ideas for adaptions for anyone that wants to do something else. Just let me know.

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Post by J3RK » Mon Apr 20, 2015 3:54 pm

The LPG and SPVCO have now been tested, and are working perfectly. :party:

Next up I'll be testing the Stereo Out Mixer, and the FadeX Plus. The first four modules will be more or less ready to go after that.

I've also started building and testing other ones too, so I'll have the next batch ready to go shortly after the first batch starts becoming available. I haven't built a new power supply for the test system yet, so I'm using my bench supplies. This makes it difficult to record audio, but I'll hook something up, even if it spans the whole room, :hihi: and get something posted in the near future.

Tracks 2, 3, and 8 in the following playlist are using identical circuits on a different PCB, if you want to get an idea of how they sound. The one difference being the LPG for Frac is a 2-pole with resonance (more like the traditional LPG) and the one in these tracks is a 1-pole with no resonance. The filter in track 8 is actually the MultiState which will be available in the second round of modules.

http://soundcloud.com/drj3rk/sets/stroh ... r-black-5u

More soon!
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Post by J3RK » Wed Apr 22, 2015 12:06 pm

I'm really enjoying this iteration of the LPG. I made a few refinements to my older designs, tweaked some values, etc. It's got a really nice sound to it now. I use VTL5C1 vactrols for it like with most of my other ones. The reason being, the dynamic range is much higher, and the response is quite a bit faster. So you can modulate it up into low audio range, which isn't possible with the slower couplers. Also, due to the extra dynamic range, you can actually just adjust the cutoff until you get a nice trail without audio leaking through. It adds quite a bit of flexibility. One can still build with VTL5C3s, but then you lose quite a bit of the higher speed modulation ability. (as is typical with most optical gates/VCAs/filters...)

I should have some time tonight to get a bit of audio recorded. :cloud:
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Post by Isaiah » Thu Apr 23, 2015 11:34 am

J3RK
Keen to hear this system in action, Dustin!

I'd love to hear an example of a Stroh Modular 258/259-ish"Complex Oscillator" patch:

Ultra-Pulse VCO and FadeX Plus - Primary Oscillator.
Set up to fade from Sine to Saw or Sine to Square, like a Buchla 258.

Multi-State Filter - Modulation Oscillator.
Either self-oscillating, or pinged while on the verge of oscillation.
LP and BP outputs mixed in varying levels (to provide quadrature outputs, right?) and sent via a VCA (Modulation Bus) to any of the following destinations:
Primary Oscillator Linear FM.
Primary Oscillator Wave Shape (Sine to Saw, or Sine to Square).

Of course, this doesn't have the wave-folding possibilities of the 259 (yet).
But you could do some potentially interesting things using a VCF as the Modulation Oscillator that a more traditional design wouldn't allow:
Feed one of the Primary Oscillator's outputs back into the Modulation Oscillator's Signal input, perhaps via a VCA.
Or, send the Saw (Ramp might work too) or Square output of the Primary Oscillator into the Modulation Oscillator's Ping input, perhaps via an attenuator for weak or strong Pings (which might be possible since you said you aren't using a Schmitt trigger).

Just a thought.
Could be brilliant, or rubbish!

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Post by Mr. Enjin » Thu Apr 23, 2015 11:49 am

:omg: I've got way too much on my plate right now but I definitely need to get busy on a couple more racks o'Frac now :blacet: :tu:

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Post by J3RK » Fri Apr 24, 2015 10:21 am

I got the Multi-State built last night. The pinging worked better than I expected. In fact, if I trim the resonance to just below full oscillation (which actually makes it sound better anyway,) it's a ton of fun.

I actually ran the gate output of my controller into the ping input, and the CV into the V/Oct, and just played the filter straight out to the console. It tracked at least 5 octaves, and was reminiscent of an electric piano. :party: Add a little audio rate FM through the second FM input, and you've got everything from bells/chimes to percussion. I think I like having it trimmed this way best, but will see if I can strike a good balance with full oscillation and clean trigger sound. I don't think it's that critical as the SPVCO has a nice clean sine, and the proposed complex VCO will have two of them as well. The filter is quite bubbly and clean this way, and the ping is delightful. I'll give it a whirl though. :cloud:

I recorded 5 demos last night, but they all had pops in them again from my stupid interface. Luckily there's a workaround, so I'll re-record some demos again tonight.

I have a couple of duplicate panels, so I may pop a couple of these modules up in the FS section soon. I have just enough PCBs to build maybe 3-4 modules, and still have a set for myself.

The full production runs with Synthcube will follow fairly soon too.

I'm going to attempt the BitBucket build this weekend. It's a big project with a lot of variables, and a lot of wiring, but if things work as expected, it's going to be a lot of fun. More soon, and hopefully non-clicky demos tonight. :party:
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Post by Isaiah » Fri Apr 24, 2015 11:05 am

Looking forward to hearing the electric piano-like pinging!
That description seems quite different from the examples I've heard of the Serge VCFQ being pinged.

I'm curious about the NWADSR. Looks like it can cycle.
Could you shed some light on functionality please?

This might be slightly off topic:
Have these PCBs become your priority over 4U, or are they being developed in parallel?

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Post by BananaPlug » Fri Apr 24, 2015 11:09 am

J3RK wrote:I got the Multi-State built last night. The pinging worked better than I expected. In fact, if I trim the resonance to just below full oscillation (which actually makes it sound better anyway,) it's a ton of fun.
Great. I agree about the trimming - go for that edge. Looking forward to hearing it and seeing how the BitBucket goes.

With the filter very near resonance, try feeding in low audio rate square around 200 Hz, tuning the filter a few octaves higher and varying the duty cycle. With certain filters it works great.

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