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Buchla 100 clones: 158, 180, 140, 156, 106, etc. DEMOS
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page Previous  1, 2, 3 ... 23, 24, 25, 26, 27, 28  Next [all]
Author Buchla 100 clones: 158, 180, 140, 156, 106, etc. DEMOS
Leverkusen
sines wrote:
I want sequence to skip a note without emitting a pulse or voltage for that step, but continue in time. Which is how the Korg SQ-1 functions to some degree.

Any ideas?


I guess the thing is that the SQ-1 is digital and implementing the same behaviour with analogue electronics is a little complicated. Therefore most analogue sequencers have either a Skip functionality which just skips the step or a Gate Off functionality to prevent outputting a gate signal. For the latter carefully dialing in the CV and/or envelope release time is important to prevent ghost notes. I don't know of an analogue sequencer that can hold a note over a 'skipped' step.

You probably could implement a circuit that switches the gate output off when a step is active, but holding the CV then would need some kind of sample and hold circuit. Otherwise you would need a circuit that counts through a row of step but on the Off-step pretend that it is still on the step before - except this was switched to Off too. That's not as simple as it seems for a human to conceptualize.

What you could do is either sequencing your clock source (140) with a second row of the sequencer to get individual length for each step. Or you could take the individual gate outs, combine them and just leave the ones out you want to be set to Off - though I don't know if you would need an OR-combiner or if it is allowed to just add them via patch cables on the Bucha 100 as you would do with e.g. Make Noise or Verbos modules.

Then here is an idea about modifying your SQ-1 for banana use: http://www.auxren.com/2017/12/how-to-bananafy-korg-sq-1.html
sines
Leverkusen wrote:
sines wrote:
I want sequence to skip a note without emitting a pulse or voltage for that step, but continue in time. Which is how the Korg SQ-1 functions to some degree.

Any ideas?


I guess the thing is that the SQ-1 is digital and implementing the same behaviour with analogue electronics is a little complicated. Therefore most analogue sequencers have either a Skip functionality which just skips the step or a Gate Off functionality to prevent outputting a gate signal. For the latter carefully dialing in the CV and/or envelope release time is important to prevent ghost notes. I don't know of an analogue sequencer that can hold a note over a 'skipped' step.


Sadly, you are correct.

Leverkusen wrote:

You probably could implement a circuit that switches the gate output off when a step is active, but holding the CV then would need some kind of sample and hold circuit. Otherwise you would need a circuit that counts through a row of step but on the Off-step pretend that it is still on the step before - except this was switched to Off too. That's not as simple as it seems for a human to conceptualize.


This is completely outside my wheelhouse for modifications at this point. smile

Leverkusen wrote:

What you could do is either sequencing your clock source (140) with a second row of the sequencer to get individual length for each step. Or you could take the individual gate outs, combine them and just leave the ones out you want to be set to Off - though I don't know if you would need an OR-combiner or if it is allowed to just add them via patch cables on the Buchla 100 as you would do with e.g. Make Noise or Verbos modules.


Without reading your response I stumbled upon this last night. I stacked the 2+5 stages from the pulse outs from the 123 to a Quad Low Pass Gate 292C, so it would give me a pulse only on 2 + 5, etc. This is what I'm searching for, but it's not all that "playable". Before I modify the 123, I could feed all of the pulse outs into a series of ON/OFF switches, then merge those collective outputs into 1 single Pulse out that would feed the LPG. Therefore I could just select which of the 8 the pulses I want to trigger the LPG.

Thinking on how I would modify the internals of the 123, I could route the Pulse outs to the input of each switch, then chain the outputs of each switch to a "selective" pulse out sad banana so that my output would just be a selection of engaged pulses. But the LEDs would need to be driven by the selected pulse out, not the master pulse input, so I'd have to drill another 8 holes for the "active/inactive Pulse" LED/switch combo or make a smaller series of LEDs for the current stage [like a tempo light].

Either way requires some work but I think this could work without any "circuitry", but rather wiring all of the pulse outs to the input of the switch, the output of the switches gets bussed to 1 master pulse out, and the LEDs are driven from the pulse out of the ... switch—LED anode to switched pulse out, cathode to ground? Is it really that simple? I am doubting myself.

Leverkusen wrote:

Then here is an idea about modifying your SQ-1 for banana use: http://www.auxren.com/2017/12/how-to-bananafy-korg-sq-1.html


Given the incredibly low cost of the SQ-1, this might be the more sane option wink
diophantine
I got my 191 assembled, and the switch correctly controls the LED! hihi

I got the HP section mostly calibrated... it doesn't seem to fully close, and it sounds a bit "scratchy" around 10-11:00, but that might be interference from something where I'm working. (It isn't the pot, because at certain positions the trimpot causes it, too.) But I only worked on it for a short while.

But I'm having difficulty with calibrating the LP section. I'm just working on pole 1 right now. I can confirm that the signal is getting into the circuit (I see it at the top of R18), but the amplitude at R12 is very low even at the best settings of R14. (Input saw = ~4Vpp, signal at R12 is ~.3Vpp.) And the DC offset is quite high, around 4V.

I got pole 1 kinda calibrated, but can't really see the signal at the next pole... (I see some sort of signal, which I can kinda affect by changing the oscillator frequency.)

What signal do you recommend using for calibration? And what frequency?
Should the frequency knob be set to FCW?
What does the trimpot R3 do, and should I try tweaking it?
What sort of max amplitude and offset do you get at the poles?

Thanks!
diophantine
Also, what's the trimpot do on the 130? Mine seems to be working fine, so I wasn't planning on touching it unless others have found it useful.

157 and 171 are working fine. I think the 172 is working, too, but the effect is very subtle on what I'm feeding it right now... and I've never really used a compressor much before, either.
lasesentaysiete
diophantine
Let me try and answer your questions smile

LP Section

Quote:
What does the trimpot R3 do, and should I try tweaking it?

R3 (and R14, R32, R72) appear to adjust the CV distribution between the matched pair of each pole. I found that these trimmers affected little. Try to set them about halfway, though.

Quote:
What signal do you recommend using for calibration? And what frequency?

I used a saw. Set the frequency so that you can make out a few cycles at whichever speed your oscilloscope is running.

Quote:
Should the frequency knob be set to FCW?

Keep the filter open when trimming each pole. That way the signal shows up on your 'scope.

Quote:
the amplitude at R12 is very low even at the best settings of R14. (Input saw = ~4Vpp, signal at R12 is ~.3Vpp.)

The amplitude will be low. This is normal. It is amplified at the output stage.

Quote:
And the DC offset is quite high, around 4V.

Dc offset was quite high on mine, too. It took quite a few turns of the trimmer to get the signal into range. I spent a good while believing that there was something wrong.

DC is later blocked at the output, so everything returns to normal smile

Quote:
What sort of max amplitude and offset do you get at the poles?


I cannot remember exactly. I would have to have another look. The numbers you are getting do not appear way off, though.


HP Section

Use RB46 & RB47 to make sure the filter closes where you want it to.
lasesentaysiete
diophantine wrote:
Also, what's the trimpot do on the 130? Mine seems to be working fine, so I wasn't planning on touching it unless others have found it useful..


The trimmer is for the decay setting. Again, exact details escape me now. Have a look on your oscilloscope. I will have a look on Tuesday when I am back at it.

diophantine wrote:

157 and 171 are working fine. I think the 172 is working, too, but the effect is very subtle on what I'm feeding it right now... and I've never really used a compressor much before, either.


The 172's effect depends entirely on the amplitude of the input. I still found some interesting sounds using the VCOs, though.

It is limited as a compressor. "Signal Leveler" seems more accurate a term, somehow.
diophantine
lasesentaysiete
Thanks! I tried the LP a bit more, this time using a sine wave (was using a sawtooth before). I got pole 1 looking alright, and pole 2 looking OK, but after that the amplitude was just too small. Hmm...

Part of the difficulty is that with my analog scope I have to set the V/Div so small to see the wave, that with all the offset there's not enough range in the vertical position knob to get the waveform in view. So I switched to AC mode, but the triggering/hold stuff with that makes it look really messy. And the amplitude with pole 2 is much smaller than pole 1, etc., so the image on the scope looks worse with every pole.

Tonight/tomorrow I may try with a square wave, and/or try tweaking R54/R55...
diophantine
Good (or at least better) news!

I set R55 FCCW and input a sine wave (to minimize any effects of filtering). Then, while monitoring R12, I adjusted R54 until I got in the area with the least distorted sine wave at R12.

After that the amplitude at each pole was much higher, and didn't decrease as much between poles (i.e. less filtering happening).

I found that it helps to have a two-trace scope with both the input wave and the pole you're adjusting. Once you think you have the trimmer right, wiggle the oscillator frequency knob and watch the scope to make sure you're looking at a version of the input signal.

Both LP and HP have a similar "scratchy" band... I was able to trim it out of the HP, but at that point the output amplitude was minimal at 3:00 and increased from there to 5:00. So tomorrow I will do some more trimming, but at this point I at least have working LP, HP, and BP! w00t


tl;dr - on the 191, even with the LP pot FCW you will probably need to adjust R54/R55 before trimming the individual poles.


btw, lasesentaysiete, I hope I never have to wire another switch like that in my life! zombie It took nearly 2 hours, and the last half hour I kept imagining Don laughing at me for not having a daughterboard to fit into those 24 pads with a bunch of CMOS switches to be controlled by a single pole switch! hihi
lasesentaysiete
diophantine
glad its working.

Something I do not think I have mentioned before is that with the internal/external switch set to external, the filters do not fully close if there is no patch cable in the appropriate plug.

regarding this:
Quote:
tl;dr - on the 191, even with the LP pot FCW you will probably need to adjust R54/R55 before trimming the individual poles.


That may be something that I forgot when I was writing the calibration notes. It may not apply to each case. Not sure. I will have a closer look this week.
lasesentaysiete
diophantine
And yeah, the switch is a treat Guinness ftw!
Leverkusen
How is the progress with the new modules and availability in the european shop?

It's peanut butter jelly time!
lasesentaysiete
Leverkusen wrote:
How is the progress with the new modules and availability in the european shop?

It's peanut butter jelly time!


I have 191 and 114 PCBs on order. They should be available by the end of the week.
sanders
I’m wrapping up a 191 build at the moment and unfortunately need to report that the 4 switches listed in the BOM (Mouser part #633-M202203, as per the BOM) are not correct for the PCB footprint. Unless I’m mistaken, or received the incorrect part, these switches have 6 pins, as opposed to the PCB footprint for 3 pins.

I’m wondering if I should cut off the extra pins and use it anyway. Opinions?
ndkent
sanders wrote:
I’m wrapping up a 191 build at the moment and unfortunately need to report that the 4 switches listed in the BOM (Mouser part #633-M202203, as per the BOM) are not correct for the PCB footprint. Unless I’m mistaken, or received the incorrect part, these switches have 6 pins, as opposed to the PCB footprint for 3 pins.

I’m wondering if I should cut off the extra pins and use it anyway. Opinions?


have not built that one but the mouser part is a DPDT (Double Pole Double throw) you want the same thing as a SPDT (single pole double throw pc mount on-none-on) -

will it work if you cut legs off?, most likely not without a modified front panel

test fit it to see for sure, I would think it won't fit the front panel if you cut off a row of legs since the legs need to be centered under the switch, save it for a different project
sanders
I didn’t look at the schematic or anything, or at the PCB before ordering. I just copy and pasted straight off the BOM; yes, i should have double checked.

I’m just hoping to save someone else from buying the wrong switches as I did, they weren’t inexpensive— probably $5 a piece (yikes). I suppose that’s the price for being the vanguard builder I am; I’ll recover : )

People beware of this 191 BOM item.

And yes, It would require some ingenuity to get the switches to sit right if I cut off one side of pins. Probably not worth the effort, and ending up with wonky switches.
lasesentaysiete
sanders
sorry about the mix up. I had already corrected the Mouser Cart with the SPDT switch. I missed the BOM file, obviously. I will correct that file tomorrow once I have access to it.
sanders
lasesentaysiete wrote:
sanders
sorry about the mix up. I had already corrected the Mouser Cart with the SPDT switch. I missed the BOM file, obviously. I will correct that file tomorrow once I have access to it.


No worries my friend, these sorts of typos are practically unavoidable when publishing such exhaustive lists of parts. It’s certainly something the builder should be double checking as well.

I know I’ve said it before, but I’ll say it again, I love these kits!! I’m so pleased that you’ve brought this beautiful historic instrument back into wider circulation.
sanders
I’m not seeing any 191 files on your website at all. Where do I find the 191 Mouser cart with the right part number? I have all sorts of SPDT switches to begin with, but I can’t find any with pins small enough to fit onto the PCB.

lasesentaysiete wrote:
sanders
sorry about the mix up. I had already corrected the Mouser Cart with the SPDT switch. I missed the BOM file, obviously. I will correct that file tomorrow once I have access to it.
lasesentaysiete
sanders
Build info for all modules is here: https://www.lasesentaysiete.com/build-info

SPDT switch Mouser#: 633-M201203
diophantine
sanders - it looks like you are using single-turn trimmers on the 191. They should be fine on R3/R21/R37/R72/RB8/RB16/RB24/RB32, but they might make trimming difficult on the others, particularly R14/R32/R48/R83. Just want to warn you...
diophantine
In other news, I just finished my 185 Frequency Shifter. Had to wait on some standoffs, as I was out of M3 M/F ones.

It seems to work! At least it outputs something that sounds frequency-shifter-ish! And it sounds cool. hihi The phasers were pretty close without trimming (will do that later, when I trim my 196, which was also very close), but I still need to trim the ring modulators.
lasesentaysiete
diophantine wrote:
sanders - it looks like you are using single-turn trimmers on the 191. They should be fine on R3/R21/R37/R72/RB8/RB16/RB24/RB32, but they might make trimming difficult on the others, particularly R14/R32/R48/R83. Just want to warn you...


Good point. I had not noticed the photo before, otherwise I would have mentioned it. R14/R32/R48/R83 will cause a headache with single turn.
lasesentaysiete
diophantine wrote:
In other news, I just finished my 185 Frequency Shifter.


I found that even with the individual modules calibrated, once combined, I had to make some adjustments.
lasesentaysiete
I managed to finish the 165 and 102 modules. They were surprisingly straightforward save a few errors on my part.

I substituted a TL071 in place of the LM307 in the 102 and found no difference. The op amp is just an output amplifier, so using a tl071 will make sourcing components a bit easier. LM307 can still be used if the builder insists.

EDIT: Here is a quick video of the 165 in action:

https://www.instagram.com/p/BzQGgjtogLM/
diophantine
lasesentaysiete wrote:
I managed to finish the 165 and 102 modules. They were surprisingly straightforward save a few errors on my part.

Excellent news! Can't wait!

Just finishing up my 114 and not sure if the CV outputs are working correctly.

With the lower pot CCW, touching the pad gives me a pressure-sensitive 0-5V.

Turning the pot CW increases the output without touching the pad, with a range of approx. 0-14V.

With the pot turned to give <5V, the pad will increase the voltage up to a max of 5V. (eg. with pot turned a bit & 2V at the output, using the pad gives a range of 2-5V output.)

When the pot is turned above 5V, the pad has no effect.

Note: all pads act identically, and I trimmed according to instructions (I assume trimming is performed when the pad is not being activated?)
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