252e details

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Chrutil
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252e details

Post by Chrutil » Fri Sep 06, 2019 4:09 pm

Hi all,
Ever since I saw the 252e for the first time I've been wanting one.
Buying one is unfortunately not an option for me, but earlier this summer my gas got to the point that I decided to try to build one myself.
I've been scouting the manual and any youtube video I have found, trying to understand all the features and I think I have most under control, but there are a few things I don't understand yet.
For example, On the CV outputs there are two LEDs on the left of each output. The bottom one seems to be red, green or blue lighting up when there is output but I am unclear of what the upper LED shows? Anyone care to elaborate?
I'm sure I will have other questions coming now that I'm starting to work on the software part...

Thank in advance!
C

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mutierend
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Post by mutierend » Fri Sep 06, 2019 7:45 pm

Bottom LED indicates which output you're programming. I can't get the top LED to light up. :)

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Chrutil
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Post by Chrutil » Fri Sep 06, 2019 8:09 pm

mutierend wrote:Bottom LED indicates which output you're programming. I can't get the top LED to light up. :)
Ha! Thanks!
Well that's intriguing - and I guess explains why it has been so hard to decipher it's functionality from available videos.
I guess I have to think of something useful to do with them then - be a shame to have them dormant :hihi:

Thanks,
C

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Oxix52
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Post by Oxix52 » Fri Sep 06, 2019 8:57 pm

I'm not in front of mine to check this, but I believe the top lights light up to indicate CV level currently coming out of the jack. The higher the CV level, the brighter the light.
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mutierend
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Post by mutierend » Fri Sep 06, 2019 9:20 pm

Oxix52 wrote:I'm not in front of mine to check this, but I believe the top lights light up to indicate CV level currently coming out of the jack. The higher the CV level, the brighter the light.
This is correct. I cranked the voltage up to 5.5 and the top LED lit up.

I had just never noticed that before. Heh.

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ArguZ
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Post by ArguZ » Sat Sep 07, 2019 2:42 am

Most LEDs have a certain starting voltage and then a non-linear curve up to their full brightness.
Only a digital system that remaps 0-10V into something like 2V to 8V exponential would accurately represent the correct level visually .
So, what we did on our blue LEDs used the the hOC or hED for example is to set them on a negative voltage of -2.1V so they start to shine at 0V already.
If you compare that to a 256e for example the first time you see some light is at 25% pot..
that is almost two octaves.
A bit much for a sequencer ;)
On the 252e the CV LED starts exactly at 2.1V

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Post by Chrutil » Sat Sep 07, 2019 10:49 am

Oh I see - ok thanks for that, I can do that, great!
I'll be using PWM for the LED brightness, so I can scale it with a non linear curve to get the brightness to appear somewhat proportional should it be needed.

Edit: Oh crap, no I can't! On my build those LEDs turns out to be tied together with the master clock LEDs that are controlled by a matrixed LED controller so they all share the same brightness.
Doh! Oh well, I will have to think of some other functionality for them.
I guess I should have asked this before I made the PCBs :bang:
No matter, though, sounds like I can live without that functionality.

Thanks!
C

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Chrutil
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Post by Chrutil » Tue Sep 10, 2019 12:32 pm

Thanks for the LED info - making good progress, but have another question.
The Cell1 pulse output should putput a pulse when cell 1 is run, but how does that work when multiple clocks are running multiple rings?
It doesn't make sense to send it out for multiple rings, so maybe it is only active for the master clock?

Thanks,
C

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Post by Citisyn » Tue Sep 10, 2019 1:46 pm

Chrutil wrote:Thanks for the LED info - making good progress, but have another question.
The Cell1 pulse output should putput a pulse when cell 1 is run, but how does that work when multiple clocks are running multiple rings?
It doesn't make sense to send it out for multiple rings, so maybe it is only active for the master clock?

Thanks,
C
It does, in fact, send a pulse whenever any of the clocks hits cell one.

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Chrutil
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Post by Chrutil » Tue Sep 10, 2019 5:57 pm

Citisyn wrote: It does, in fact, send a pulse whenever any of the clocks hits cell one.
Thanks Citisyn, I appreciate that!
That seems like an odd feature, if the clocks are 'freerunning' or 'sync cycle' I can't think of a good use for that, but I guess use cases comes with experimentation -
my original thought would be to use cell1 for switching ring, but since it goes one more loop when you do that I guess the way to do that is to allocate another pulse channel and put a step on the last cell instead.

Thanks!
C

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Post by Chrutil » Thu Sep 12, 2019 6:26 pm

...almost there..
I have some software library conflicts that is delaying the demo of this project, but I'll get there - meanwhile I'm working on a deeper understanding of some of the more esoteric 252e functionality.

That said, can someone clarify behind/ahead for me?
The manual simply states it pushes the cell behind or ahead in the sequence.
Since it turns left/right it would intuitively (to me) mean the cell is performed earlier if turned to the left, but that's called behind, so maybe it is the other way?
Also this implies that timing-wise it is intruding on the previous or next cell.
So in case behind means earlier, if the first row is the standard clock, are the second and third row how the cell timing is pushed for behind and ahead?

Image


Also, the cell subdivide knob ranging from 0 through 1/3 and 2/3 to 1 does that mean the starting point in the cell where the subdivisions begin?
Say at 0 if we have two pulses we get: [*...*...]
and at 1/2 we get [....*.*.]
and if set to 1 we get [......**]

Also, I can see from the demos that subdivide set to 2 makes two pulses,
but that should mean that both 0 and 1 will generate 1 pulse -
does 1 then mean that the single pulse is also sent to the subdivide output?

Many thanks,
C

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Post by Happyanimal » Thu Sep 12, 2019 7:56 pm

Behind/ahead is microtiming or can be thought of swinging the note ahead of or behind the beat.

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Chrutil
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Post by Chrutil » Fri Sep 20, 2019 2:46 am

Thanks to everybody who has helped me figure this thing out!
I have spent the summer trying to figure out how to build one of these for myself, and it is finally starting to come together.
I still have ways to go, but here's a first quick preview of the project so far:

https://www.youtube.com/watch?v=fOmBG37Rgw4

C

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Post by Synesthesia » Fri Sep 20, 2019 5:27 am

waow.... pretty amazing!!! great job :)

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Post by djs » Fri Sep 20, 2019 7:29 am

This thing is way awesome. Care to share what it looks like on the backside? Or start a thread in the diy subforum about it?
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Post by Kent » Fri Sep 20, 2019 8:15 am

That is super-cool. I'm assuming that it is a re-housed original 252e, right? Outside of the knobs, display and jacks, it appears to be so. Nonetheless, still a monumental amount of effort!

:yay:

Also, what is the purpose of the display? The original doesn't require one. I've only seen it showing selected ring, which is a bit redundant. Are you working on incorporating the display to provide more?
I do like the nice touch of implementing jacks for individual clock I/O per active ring. Are they functional at this time?

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Post by bwhittington » Fri Sep 20, 2019 8:24 am

Kent wrote:That is super-cool. I'm assuming that it is a re-housed original 252e, right? Outside of the knobs, display and jacks, it appears to be so. Nonetheless, still a monumental amount of effort!
In the yt vid he talks about writing the software. Looks like he did this from the ground up. Really awesome work. :woah: :tu: :party:

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Post by Chrutil » Fri Sep 20, 2019 8:54 am

Thanks for the nice words all!
Kent wrote:I'm assuming that it is a re-housed original 252e, right? Outside of the knobs, display and jacks, it appears to be so.
No it's all custom.
Like I mentioned in the youtube comment, I have never atually seen a real 252e, thus all my questions about how it works here :lol:
It's based around a Teensy 3.6 microcontroller.
Most of the circuitry is pretty standard, the LED circle is basically 192 2mm RGB LEDs with lasercut acrylic in a pattern for the diffusers and cell structure.
Kent wrote: Also, what is the purpose of the display? The original doesn't require one. I've only seen it showing selected ring, which is a bit redundant. Are you working on incorporating the display to provide more?
I do like the nice touch of implementing jacks for individual clock I/O per active ring. Are they functional at this time?
The display is there for a couple of reasons.
Mainly because I really like VFDs :hihi:
But really, on the original there are a set of smaller displays for specific purposes. Thats hard to incorporate into the panel, so I just put one larger display there. I haven't really programmed anything for it yet, but it'll have some purpose.
There is also MIDI and it will also be load/save onto an embedded SD card since it lives on its own.

Here's a photo of the back, complete with patched PCB mistakes :)
Image

Thanks,
C

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Kent
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Post by Kent » Fri Sep 20, 2019 9:17 am

Incredible work, sir. You truly live up to the title of Sr. Software Engineer! Bravo.

:sb:

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Post by elmerfudd » Fri Sep 20, 2019 10:03 am

Freaking Awesome and humbling. Masterful work.

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mutierend
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Post by mutierend » Fri Sep 20, 2019 10:50 am

I cannot believe you did this without actually using a 252e. I'm blown away by your work.

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Post by gaslampmusehog » Fri Sep 20, 2019 10:52 am

Great work!

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Post by momo » Fri Sep 20, 2019 2:56 pm

Incredible! Bravo!!

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lumin
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Post by lumin » Fri Sep 20, 2019 9:11 pm

my mind is blown. fantastic job!

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Post by Leoespejo » Sat Sep 21, 2019 5:49 am

Amazing job !!!

Tha only think I miss on the 252e is that you can't drive the 3 different clocks with 3 external triggers, it would be great to be able to move each at different speeds.

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