PMB The buchla 208r rev2and 208 Bemi preset manager box

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phutureboy
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Post by phutureboy » Fri Aug 21, 2015 10:50 am

captnapalm wrote:I talked to Yasi a few years ago about a patch storage system for the vintage Easel. He said at the time that he thought it would be possible to "read" the current levels with the mu at the 208's outputs. That way you'd be able to make a patch with the front panel as usual, then push one button and save that patch for use later. That sounded amazingly useful to me.
The BEMI iProgram card does exactly that and many sources tell me it should work with the original Easel/208r as well...
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Post by ttown23 » Fri Aug 21, 2015 11:54 am

phutureboy wrote:
captnapalm wrote:I talked to Yasi a few years ago about a patch storage system for the vintage Easel. He said at the time that he thought it would be possible to "read" the current levels with the mu at the 208's outputs. That way you'd be able to make a patch with the front panel as usual, then push one button and save that patch for use later. That sounded amazingly useful to me.
The BEMI iProgram card does exactly that and many sources tell me it should work with the original Easel/208r as well...
AFAIK, the BEMI iProgram card does not work 100% with the vintage easel/208r rev. 2, due to circuitry differences between those and the new BEMI Easel. This, from Todd Barton- I have not personally done the comparison.
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phutureboy
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Post by phutureboy » Fri Aug 21, 2015 12:03 pm

I'd be curious to hear from Todd what does work and what doesn't...
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Post by papz » Fri Aug 21, 2015 2:39 pm

I just tested my special program card I did for my 208r rev2 on a BEMI Easel which visits me currently and everything works as with the 208r rev2.
Only difference is the sequencer 2-stage switch which make it play 3 stages when the switch is set to 5, but this is probably a matter of resistor value only.

So if some contacts are different actually, are not the ones related to :
- 2 step sequence switch
- keyboard/pulser trigger switch for the sequencer, to sum with the one of the panel switch
- sequencer stages CV via a "to card" banana
- switch to select if the signal at the other "to card" banana is routed to the MO or to the CO waveshape
- keyboard/pulser trigger switch for the random generator, to sum with the one of the panel switch
- sequencer trigger switch for the random generator
- MO hi/lo frequency switch
- attack variable CV input
- keyboard trigger switch for the envelope, to sum with the one of the panel switch
- duration variable CV input
- decay variable CV input
- keyboard trigger switch for the pulser, to sum with the one of the panel switch
- CO waveshape level variable CV input
- envelope output and trig in
- +15V / -15V / ground

Anyway, if some contacts are differently positioned on the BEMI Easel, it shouldn't be difficult to adapt the program card, the preset manager or the instrument. It's only routing...
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Post by boops » Fri Aug 28, 2015 7:53 am

Last board is finished ,the mother board...

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sascha.victoria
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Post by sascha.victoria » Fri Aug 28, 2015 10:03 am

If I recall the 208r rev2 can be set to 1v/oct, 1.2 v/oct, or 2v/oct. Does you program card address all of those settings or does it need to be set to one in particular?
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Post by sduck » Fri Aug 28, 2015 12:11 pm

sascha.victoria wrote:If I recall the 208r rev2 can be set to 1v/oct, 1.2 v/oct, or 2v/oct.
I don't think so. There's nothing like that on mine.
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captnapalm
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Post by captnapalm » Fri Aug 28, 2015 1:34 pm

sduck wrote:
sascha.victoria wrote:If I recall the 208r rev2 can be set to 1v/oct, 1.2 v/oct, or 2v/oct.
I don't think so. There's nothing like that on mine.
IIRC only the Rev1 is configurable that way, but the rev2 can be modified with resistor changes.

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Post by papz » Fri Aug 28, 2015 3:47 pm

You have to change resistors also on the rev1.
From memory neither 1V/oct nor 1.2V/oct tracking could be achieved with the original factory SMT ones.
I don't think this could be set via the program card slot without modification of the 208.
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Post by boops » Sat Aug 29, 2015 7:05 am

sascha.victoria wrote:If I recall the 208r rev2 can be set to 1v/oct, 1.2 v/oct, or 2v/oct. Does you program card address all of those settings or does it need to be set to one in particular?



Atm ,it seems the 1U 19" rack is the choice ,Please comment.
Perhaps a mega easel with 2x 6U boats,a preset manager 2U,and the Breaking box hardware Bananas in/out Cv (next project)2U too????
FS :custom buchla 203 style càbinet ,skiff new design,boat ,hardware for diy cabinet ,easel case ,new 1u to 10u to 56u and more. / New 208 buchla card 12 /
HQ small case buchla psu PCB
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Post by boops » Sun Aug 30, 2015 6:15 am

Well : we are actually on 2v/octave, but it's only a software configuration.
In the Arduino DUE, we must translate keys -> "voltage" (virtual) with a scale table (the scale you choose/want or develop - Arduino !) -> output CV.
So any factor can be used (in a LCD menu, configure your volt/octave).

By the way, we think to use MIDI pitch bend : but there is no limit to number of octaves (why not +- 5 or more ? it's just a variable in the Arduino software : we think of 2 variables : 1 for bend up, the other for bend down - so one can play the Moog chorus from "I want to get free", by Qeen).
FS :custom buchla 203 style càbinet ,skiff new design,boat ,hardware for diy cabinet ,easel case ,new 1u to 10u to 56u and more. / New 208 buchla card 12 /
HQ small case buchla psu PCB
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Post by askthedust » Sun Aug 30, 2015 7:09 am

papz wrote:You have to change resistors also on the rev1.
From memory neither 1V/oct nor 1.2V/oct tracking could be achieved with the original factory SMT ones.
I don't think this could be set via the program card slot without modification of the 208.
Didnt have to switch resistors to tune my rev1 to 1v/oct

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Post by boops » Sun Aug 30, 2015 8:56 am

UPDATE

Image

Image
FS :custom buchla 203 style càbinet ,skiff new design,boat ,hardware for diy cabinet ,easel case ,new 1u to 10u to 56u and more. / New 208 buchla card 12 /
HQ small case buchla psu PCB
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razzmtazz266
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Post by razzmtazz266 » Sun Aug 30, 2015 12:46 pm

:bananaguitar: :bananaguitar: :bananaguitar: :bananaguitar:
sounds amazing.....is there any word on cost yet?

J

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Post by papz » Sun Aug 30, 2015 6:52 pm

askthedust wrote:Didnt have to switch resistors to tune my rev1 to 1v/oct
Probably because it was already done by the builder before it was sold to you.
Finest EMS gear service and Music Easel/208 goodies

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Post by boops » Mon Aug 31, 2015 9:13 am

razzmtazz266 wrote::bananaguitar: :bananaguitar: :bananaguitar: :bananaguitar:
sounds amazing.....is there any word on cost yet?

J
I will make a preorder ,if enough quantity we will have the pcbs cheaper
The price is not calculate yet.
FS :custom buchla 203 style càbinet ,skiff new design,boat ,hardware for diy cabinet ,easel case ,new 1u to 10u to 56u and more. / New 208 buchla card 12 /
HQ small case buchla psu PCB
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Post by boops » Tue Sep 15, 2015 3:12 pm

New
http://www.amazon.fr/Official-Raspberry ... uch+screen

We Try atm to implant this 7" touch screen for a nice Gui interface
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HQ small case buchla psu PCB
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Post by wsy » Sun Oct 18, 2015 11:40 am

An interesting point: I found the ancient '73 schematics for the 208 on the web here

http://rubidium.dyndns.org/~magnus/synt ... es/buchla/

and unless I'm misreading them, all of the front-panel pots are 50Kohm, with a pair of 120K ohm "bracketing" resistors.

But that doesn't make sense compared to the programming card; there, it looks like adding a 240K is half-scale on the pot, which would
be _full_ scale on the bracketed system. Worse, there's no way at all for the bracketed system to achieve any higher resistance,
so a 1 (at 1.2 megohms) is unachieveable. Clearly, I do not understand.

- Bill
"Life is short. But we can always buy longer patch cords" - Savage

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Post by boops » Sun Oct 18, 2015 5:59 pm

wsy wrote:An interesting point: I found the ancient '73 schematics for the 208 on the web here

http://rubidium.dyndns.org/~magnus/synt ... es/buchla/

and unless I'm misreading them, all of the front-panel pots are 50Kohm, with a pair of 120K ohm "bracketing" resistors.

But that doesn't make sense compared to the programming card; there, it looks like adding a 240K is half-scale on the pot, which would
be _full_ scale on the bracketed system. Worse, there's no way at all for the bracketed system to achieve any higher resistance,
so a 1 (at 1.2 megohms) is unachieveable. Clearly, I do not understand.

- Bill
Preset card is current based
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Post by wsy » Sun Oct 18, 2015 7:51 pm

boops wrote:
wsy wrote:An interesting point: I found the ancient '73 schematics for the 208 on the web here

http://rubidium.dyndns.org/~magnus/synt ... es/buchla/

and unless I'm misreading them, all of the front-panel pots are 50Kohm, with a pair of 120K ohm "bracketing" resistors.

But that doesn't make sense compared to the programming card; there, it looks like adding a 240K is half-scale on the pot, which would
be _full_ scale on the bracketed system. Worse, there's no way at all for the bracketed system to achieve any higher resistance,
so a 1 (at 1.2 megohms) is unachieveable. Clearly, I do not understand.

- Bill
Preset card is current based
Oh, I understand that; that's obvious given that the LOW values on the sliders correspond to very high resistance
values (1.2 megohm at 1). What's baking my noodle is how the same values get generated by the front panel sliders, because it
would be crazy to have some transconductance circuit in there so that the program card can be current-based and the front panel be voltage-based.

Besides, I know the front panel has some current attributes. If you patch two modulation sources together to (for example) the pitch of the
complex oscillator, the result is a mixture of the two modulation sources. And, at least in the case of the pulser, the pulser is NOT
sufficiently isolated or buffered; a very low (near 0) value output by another modulation source can keep the pulser from cycling;
remove that value, and the pulser continues pulsing.

See, my plan is this: given that the card programming resistances are current-based; they go into some resistance. AND- when
the program switch is in the "BOTH" position, the card and the front panel both take effect (I believe they add; in effect, you can go "up to 11").

So, treat the unknown front panel current source as an unknown impedance and apply a pulsing drive signal through a known
(and variable) impedance. When the output node swings twice the voltage, then your known variable impedance is equal to the
unknown impedance - that is, equal to the front panel slider position.

That's how I'm thinking how to autorecord slider positions; you would put the switch into the "BOTH:" position and the Arduino would
wiggle each output ("to sound generator") node as desired, while looking at the input nodes; detecting "wiggle" indicates that
a patchcord is routing that input to that output. Then use the impedance trick above to figure out the setting of the slider.

And the digital-resistance matrix to emulate the card isn't hard either- there are only
six modulation inputs from eight available
modulators (sequencer, EG, pulser, pressure, and four independent randoms). So 48 digitally-settable resistance cells is
sufficient for the modulation matrix (you need at least 15 more for the sliders that don't connect to the jacks, so you can just do the
impedance mirror trick to get those settings.

But this is all predicated on a particular way the program card might or might not work, and I'm not sure it works that way or not.

- Bill
"Life is short. But we can always buy longer patch cords" - Savage

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Post by boops » Tue Jan 12, 2016 9:50 pm

FYI...
All the schémas and Gerber are almost finished...There are 15 little pcbs In the PMB (preset manager box),and There are 3 slots empty for future expansion.
FS :custom buchla 203 style càbinet ,skiff new design,boat ,hardware for diy cabinet ,easel case ,new 1u to 10u to 56u and more. / New 208 buchla card 12 /
HQ small case buchla psu PCB
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Post by MATSmile » Wed Jan 13, 2016 1:29 pm

boops, Are you planning it as DIY or pre-build?

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Post by boops » Mon Feb 22, 2016 4:27 pm

hi
Things go slowly but almost of the pcbs (15) are ready to production
The difficulty is to keep a decent price ,more soon
Here the pcb of switches 1 of 2
Image
FS :custom buchla 203 style càbinet ,skiff new design,boat ,hardware for diy cabinet ,easel case ,new 1u to 10u to 56u and more. / New 208 buchla card 12 /
HQ small case buchla psu PCB
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Post by boops » Mon Feb 22, 2016 5:22 pm

MATSmile wrote:boops, Are you planning it as DIY or pre-build?
If possible à partial diy :hmm:
FS :custom buchla 203 style càbinet ,skiff new design,boat ,hardware for diy cabinet ,easel case ,new 1u to 10u to 56u and more. / New 208 buchla card 12 /
HQ small case buchla psu PCB
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Post by scottmoon » Mon Feb 22, 2016 8:53 pm

:tu: nice boops
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