Improbability Drive Mods - External S&H + More

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Muff Wiggler
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Improbability Drive Mods - External S&H + More

Post by Muff Wiggler » Mon Mar 31, 2008 2:47 pm

Thanks BananaPlug for the info&photo, and for permission to post his work here!
BananaPlug wrote:Hi Folks,

The Blacet ID2510 (fancy noise source) has a lot of blocks in its block diagram. These simple mods give you a little more access. The usual disclaimers apply: don't get in over your head, forget about your warranty, etc. Also, I made mine with banana plugs so where I've added a jack and a switch you would probably use a switching mini-jack. I used very stubby switches so they don't crowd the knobs.

#1 There's a multi-mode filter with a switch that lets you select band pass or low passed noise as an input to a sample and hold. The output of the S&H feeds a quantizer and both outputs are available at the panel. Mod #1 lets you feed the S&H / quantizer with an external signal.

Add the jack & SPDT switch. Wire the jack to one side of the new switch. Take the wire off the center lug of the existing switch (Filter LP/BP) and move it to the center lug of the new switch. Run a new wire between the two remaining switch lugs.

#2 That quantizer is a nice piece of work. Good Mister Blacet even provided a choice of four scales using a little trim pot on the PCB. This mod simply remotes it to the front panel.

Remove RT2. Install a 50K linear pot on the panel. Hook up the three wires. Piece-o-cake.

#3 This one doesn't really count. A choice of internal or external S&H clock is a standard feature accomplished with a switching jack. When I bananafied this module I needed to add a switch.

That's enough for me but if you like drilling holes I suppose it wouldn't be too hard to provide patch points for the in and out of the filter.

Enjoy!
Image

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Post by tragedybysyntax » Mon Oct 20, 2008 11:05 am

Oh snap.... I have to do #1 and #2 this week! I just got my ID in the mail today and I"m stoked as a mofo to finally have a noise source in my rig!!! YIPPEEEE!!! :)

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Post by haricots » Mon Oct 20, 2008 10:26 pm

I've never understood why the scale function was only available via a trimmer. These mods look pretty cool - I'm night have to try.

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Post by Cat-A-Tonic » Mon Jun 14, 2010 9:42 am

I decided to take a slightly different approach to Bananaplug (although I must give praise for the inspiration).

I put the input before the filter using a switching jack.
When nothing is plugged into it, it is normalled to the mixed noise as usual.

Cut the trace leading from the center lug of the mixed noise pot to pin 1 of RN6.
Wire the switching lug of your jack to the small pad on one side of this trace.
Wire the signal lug of your jack to pin 1 of RN6.

When using it as a Sample & Hold, the filter acts kind of like a VC slew/lag. Yummy timbral variety.

When using it as a VC Filter, the Sample & Hold rate knob gives it growly modulation. This was a surprise bonus.

Pics help to explain the process:
Image
The ID is surrounded by friends that (when used together) perform similar functions.

Image

Image

Image

I am really fucking happy with how these modifications turned out. :party:
Thanks a lot to BananaPlug & Muff for this awesome thread! :goo:

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Post by BananaPlug » Mon Jun 14, 2010 10:29 am

Nice work & great pix! :banana:

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Post by Cat-A-Tonic » Mon Jan 23, 2012 9:29 am

I love this module.

The VC Filter/S&H&Quantizer input mod adds so much.

and the Quantizer Scale Select knob on the front is pretty damn convenient.

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Post by solitaryzen » Mon Jan 23, 2012 7:22 pm

That input & quantiser scale select would be really handy.

One thing that has puzzled me with my ID is the comparatively small range of the s/h output. Is that normal, or should I be getting just us much depth as any other s/h module (and yes, I'm talking about when the filter is fully open).

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Post by Cat-A-Tonic » Mon Jan 23, 2012 8:07 pm

solitaryzen wrote:One thing that has puzzled me with my ID is the comparatively small range of the s/h output. Is that normal, or should I be getting just us much depth as any other s/h module (and yes, I'm talking about when the filter is fully open).
I changed a R31 from 47k to 100k to increase the noise level of mine.
This extends the range of the S&H/Quantizer when used normally.
This is a case by case mod depending on the noise transistor in each unit.

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Post by solitaryzen » Mon Jan 23, 2012 8:18 pm

Thanks for that info - I think mine must be one with the low noise level.

pulse_divider

Post by pulse_divider » Tue Jun 18, 2013 12:08 pm

Cat-A-Tonic wrote:
solitaryzen wrote:One thing that has puzzled me with my ID is the comparatively small range of the s/h output. Is that normal, or should I be getting just us much depth as any other s/h module (and yes, I'm talking about when the filter is fully open).
I changed a R31 from 47k to 100k to increase the noise level of mine.
This extends the range of the S&H/Quantizer when used normally.
This is a case by case mod depending on the noise transistor in each unit.
Thanks for the tip! My secondhand unit was only hitting the first LED on my bar graph (so roughly 1 +/-.5 V) and had a 56k resistor at R31. I just subbed a 180K and now it swings up to the 4th LED with no problem so I'm getting probably just under 5V output, which is perfect.

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Post by otoskope » Mon Oct 28, 2013 7:23 pm

I just did a couple of these, but when trying Cat-a-Tonic's version of inserting an external signal before the filter, I get some signal leak/disturbances on the "OUT" signal that is related to the S/H clock (the lower one, that goes to quantizer stage). Some clicking there that varies when changing the S/H clock freq. It goes away when I switch to external clock.

So, to trouble-shoot this, and to try to find a way to inject external signals into the window comparator, I'd need the schematics. I bought it used from Fidgit, and no schematics came with it. Anyone could help me with this? I understand we can't post them, but a PM or so would be wonderful!

Thanks,
Palle
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Post by otoskope » Tue Oct 29, 2013 4:08 pm

OK, too impatient. No schematics found, but I did some detective work and solved it. Here's a new mod that gives you a signal input before all processing stages, so that you can use the ID as a modulatable waveshaper/clipper/filter thingy, for arbitrary signals, and then use this as your S/H source. All original functionality is retained.

A switch choses between this new input signal and the original white noise. With the switch in the noise position, all original functionality is retained. The "WHITE" output jack continues to output white noise at all times, but the "DIGITAL" jack now outputs clipped/processed input signal or "digital" noise, according the the switch.

The idea is simply to cut the connection between the internal white noise source and here inject whatever signal instead, before all processing stages. In this way you can use the ID to shape/clip a signal (the processing that normally creates the "digital" noise from white noise), to filter it, or to S/H it, or all three of them.

The shaping/clipping process is actually a clipper from below and above, with individual controls of each, but the below limit setting (WIDTH) is controlled relative the above limit (LEVEL). This is what happens with the "digital" noise shaping, but it doesn't hurt to think about what it actually does when shaping oscillator waves, etc.

Especially nice waveshaping results can be had when mixing processed and clean signal (with the "DIGITAL/WHITE" knob), and when modulating LEVEL and WIDTH with LFOs, for example.

The mod involves one new SPDT switch, one new jack, two cut traces and a couple of jumper leads. Mine is bananafied - if you're on jacks, a switching jack makes the switch redundant.

This is how you do it (see pics below for clarifications):
* Cut the trace close to the middle leg of of the noise level trimmer RT1, on the component side, before it forks out (important!).
* Cut the trace between R24 and U7, close to the resistor leg, before the through-hole, on the solder side.
* Solder a jumper lead between RT1's middle leg and R24 (same end as the cut trace). I did this on the solder side of the board, but it can be done on either side. This lead provides white noise to the white noise jack, regardless of the setting of the new switch.
* From the same point on the RT1 middle leg, solder one more lead, this time to one lug of the SPDT switch.
* Solder a lead from one of the through-holes in the lead previously connected to the RT1 middle pin (but now cut), to the middle lug of the new switch. This is the blue cable in the pic.
* Solder a lead from the last lug on the switch to the new input jack (yellow jack in the pic).

One the modules shown, I have also added a switch for external S/H clock, since the banana jack is not switching (duh!).

I plan to do the scale select knob mod too, but have to order parts...
Good luck modding!

Image
Image
Image
edit: There's a slight error in the above picture. The "WHITE/DIGITAL" fade knob blends unprocessed and shaped/clipped noise or signal BEFORE the filter. The mix goes into the filter, then to the "OUT" jack.
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Post by Cat-A-Tonic » Tue Oct 29, 2013 7:12 pm

Awesome work otoskope!

The 'clipper' is a window comparator.

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Post by otoskope » Tue Oct 29, 2013 7:58 pm

Cat-A-Tonic wrote:The 'clipper' is a window comparator.
I know, but when using it on oscillator waves, especially mixing in the original wave, it behaves more like a waveshaper. Also, on the broadband noise signal, there are lots of spikes at the transitions (maybe due to transition times for the analogue switches involved) making it behave not entirely as a window comparator. This contributes a lot to the lovely crackling noise the ID is capable of. I spent an hour or two in front of the oscilloscope today :love:

I should also say a great thanks to you and Bananaplug for inspiring me to do it. What we've done is essentially pushing the insert point closer to the source, step by step.
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Post by otoskope » Tue Oct 29, 2013 8:08 pm

I am also fully aware that a lot of what I wrote is old news for you ID veterans. I just had mine for a very short time. Take it as a sign of enthusiasm :banana:
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am I understanding this right?

Post by dhamaryder » Fri Apr 11, 2014 4:06 pm

Using Mod#1 will this allow me to use the quantizer with an external input?
I mean, not necessarily with another noise signal but say a varying control voltage?
If so I'm definitely adding this Mod.

thanks,
steve

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am I understanding this right?

Post by dhamaryder » Fri Apr 11, 2014 7:21 pm

Using Mod#1 will this allow me to use the quantizer with an external input?
If so I'm definitely adding this Mod.

thanks,
steve

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Post by dhamaryder » Mon Apr 14, 2014 3:45 pm

Dear MuffWiggler, I have a question about the Mod you put up for the Improbability Drive. Here are your instructions for the #1 Mod:

"Add the jack & SPDT switch. Wire the jack to one side of the new switch. Take the wire off the center lug of the existing switch (Filter LP/BP) and move it to the center lug of the new switch. Run a new wire between the two remaining switch lugs."

Does that last sentence mean to add two wires and connect each of the outer lugs of the existing switch with the two outer lugs of the new switch? I'm just not sure what that last sentence means exactly.
thanks,
steve
PS I've already taken out that 50K pot of the quantizer to the front panel. Works great.
And changed R31 to a 100K which fixed my very low output of the S/H.

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Post by diophantine » Sun Apr 30, 2017 9:17 am

Just want to suggest a quick enhancement to the mod for the external S&H input. I did it last night with just a switching jack and it worked perfectly. However, you'll note that the filtered noise output is now just a copy of the S&H input signal. Easy fix: disconnect the signal wire from J4 to the PCB, and wire a 100 ohm resistor from the jack signal lug to the middle pin of the switch.

I also moved the scale select pot to the front panel. Since there's only 4 settings I didn't want a big pot + knob. So I used one of these guys:
http://smallbear-electronics.mybigcomme ... tic-shaft/

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