No go's for the Buchla Music Easel?

Discussing some incredible modules that don't quite fit into the other forum categories.

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01235813
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No go's for the Buchla Music Easel?

Post by 01235813 » Tue May 28, 2019 12:07 pm

Hello,

new wiggler here. I saw the music easel for the first time in 2011. I cannot put in words the fascination that I have developed over the years. Then in 2013 BEMI released one making it possible for me to save and acquire one. (Money alone wasn't enough, these gadgets are hard to come by) Finally after transferring the full amount in advance and good spirit, six months later I received my BUSA easel. Beautiful if I may say so.

I am new to Modular. I bought the easel because it was a calling I cannot put into words. The first moments were beautiful and we hit it off right away.. tons of fun!

To my question, please bear with me, I am new to the genre.

Is there anything that I should not be patching? I read somewhere that one shouldn't pass more that one output voltage into a single input (black). I have seen videos of people doing so.

Is there anything that I can do in terms of patching that will harm the easel?

Are there any other general "no go's" that a beginner should beware of and avoid?


Cheers

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lumin
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Post by lumin » Tue May 28, 2019 4:43 pm

There are some threads concerning your question, so I would suggest a search. But an immediate answer is to avoid patching outputs (the colored banana jacks) to other outputs. It is ok to patch multiple outputs to a single black input. It's how you attain some interesting rhythms/textures.

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Post by mutierend » Tue May 28, 2019 6:08 pm

lumin wrote:There are some threads concerning your question, so I would suggest a search.
Search is currently broken, just fyi.

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Post by slam » Tue May 28, 2019 7:13 pm

lumin wrote:There are some threads concerning your question, so I would suggest a search. But an immediate answer is to avoid patching outputs (the colored banana jacks) to other outputs. It is ok to patch multiple outputs to a single black input. It's how you attain some interesting rhythms/textures.
What happens if you patch output to output?

I’ve never tried that but I do patch multiple outputs to inputs all the time.

I think the easel is fairly robust. I don’t think there I much in normal patching that can harm it.

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Post by Ginko » Wed May 29, 2019 8:53 am

slam wrote:
lumin wrote:There are some threads concerning your question, so I would suggest a search. But an immediate answer is to avoid patching outputs (the colored banana jacks) to other outputs. It is ok to patch multiple outputs to a single black input. It's how you attain some interesting rhythms/textures.
What happens if you patch output to output?

I’ve never tried that but I do patch multiple outputs to inputs all the time.

I think the easel is fairly robust. I don’t think there I much in normal patching that can harm it.
This doesn't particularly make sense to me, if you patch two outputs to an input, you are effectively patching an output to an output in the process. Patching an output to an output ought not to do anything, but it shouldn't do any harm.

Regarding the OP, and as search isn't working, there is some rumour that 'circuit bending' the program card (using your fingers to bridge points on it in place of resistors, as demonstrated towards the end of a Charles Cohen video) can cause damage to the Easel. I have seen it suggested that this is down to the supply rails being broken out on the card, so you could apply an 'out of spec' voltage to somewhere you shouldn't. It has been suggested that cutting the traces for the supply rails on the PCB could protect against this.

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Post by 01235813 » Wed May 29, 2019 1:31 pm

Thanks for the replies.
lumin wrote:There are some threads concerning your question, so I would suggest a search. But an immediate answer is to avoid patching outputs (the colored banana jacks) to other outputs.It is ok to patch multiple outputs to a single black input. It's how you attain some interesting rhythms/textures.
I was hoping to hear something along the lines of this. For example:

I was wondering if one could patch the output of the EG (Self triggered) and output the pulser (different timing) to the same input to achieve some type of polyrhythmic expression. Does anyone have any experience along these lines. Seems to me like an intuitive thing to do.

Concerning the search.. I have spent years lurking and hadn't seen anything of the nature; nor did a filtered google search help. I doubt not that there are threads somewhere of this nature. Anyone have a link?

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Post by Ginko » Wed May 29, 2019 1:49 pm

01235813 wrote:Thanks for the replies.
lumin wrote:There are some threads concerning your question, so I would suggest a search. But an immediate answer is to avoid patching outputs (the colored banana jacks) to other outputs.It is ok to patch multiple outputs to a single black input. It's how you attain some interesting rhythms/textures.
I was hoping to hear something along the lines of this. For example:

I was wondering if one could patch the output of the EG (Self triggered) and output the pulser (different timing) to the same input to achieve some type of polyrhythmic expression. Does anyone have any experience along these lines. Seems to me like an intuitive thing to do.

Concerning the search.. I have spent years lurking and hadn't seen anything of the nature; nor did a filtered google search help. I doubt not that there are threads somewhere of this nature. Anyone have a link?
Earlier today I was trying to mix the sequencer out with the preset voltage on the 218 to the CO pitch input and this totally didn't work for some reason. I was hoping to shift the sequence by a couple of semitones. Basically the sequence CV just continued with no effect. I will try again at some point because that doesn't seem right. That said, you do typically want a summing circuit to combine analogue signals

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Post by 01235813 » Thu May 30, 2019 5:30 am

Ginko wrote:
slam wrote:
lumin wrote:There are some threads concerning your question, so I would suggest a search. But an immediate answer is to avoid patching outputs (the colored banana jacks) to other outputs. It is ok to patch multiple outputs to a single black input. It's how you attain some interesting rhythms/textures.
What happens if you patch output to output?

I’ve never tried that but I do patch multiple outputs to inputs all the time.

I think the easel is fairly robust. I don’t think there I much in normal patching that can harm it.
This doesn't particularly make sense to me, if you patch two outputs to an input, you are effectively patching an output to an output in the process. Patching an output to an output ought not to do anything, but it shouldn't do any harm.

Regarding the OP, and as search isn't working, there is some rumour that 'circuit bending' the program card (using your fingers to bridge points on it in place of resistors, as demonstrated towards the end of a Charles Cohen video) can cause damage to the Easel. I have seen it suggested that this is down to the supply rails being broken out on the card, so you could apply an 'out of spec' voltage to somewhere you shouldn't. It has been suggested that cutting the traces for the supply rails on the PCB could protect against this.
Thanks for that bit about the circuit bending. I have seen the video you mentioned and found that to be ever so appealing.

I just read that removing/inserting the iprogram card while the easel is powered on can result in damage. I have seen Mr. Cohen remove regular programming cards whilst powered on so I'm gonna assume that there is a difference between iprogram card and the programable cards.

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Post by tarandfeathers » Thu May 30, 2019 11:39 am

Ginko wrote:Regarding the OP, and as search isn't working, there is some rumour that 'circuit bending' the program card (using your fingers to bridge points on it in place of resistors, as demonstrated towards the end of a Charles Cohen video) can cause damage to the Easel. I have seen it suggested that this is down to the supply rails being broken out on the card, so you could apply an 'out of spec' voltage to somewhere you shouldn't. It has been suggested that cutting the traces for the supply rails on the PCB could protect against this.
This is not accurate. The resistance of your skin is pretty high even over a short distance, very little current is going to pass even across the maximum differential voltage of 30V. If you short across the power rails directly with a metal or other low resistance object you could cause the power supply to shut down (or damage it or the traces between it or the program card interface if the PSU design is poor).

The possibility of damage is due to the fact that there are pins on the program card interface that connect directly to CMOS devices with no additional protection against ESD. These days most devices have some protection built in but if you are charged up from walking across the carpet in your socks and you touch the wrong trace you could probably still zap something.
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Post by tarandfeathers » Thu May 30, 2019 11:51 am

Also, generally speaking, you can connect pulse outputs together if they have series diodes, from memory this is not the case for any output on the 208. Other Buchla designs do have these diodes so you can stack multiple pulse outputs together.

CVs are a different situation all together, you're connecting (hopefully) low impedance outputs to (hopefully) high impedance inputs. The output with the highest drive capability will "win" and swamp the others, or the outputs will interact with each other. Depending on the design of the device driving the outputs this may or may not cause damage but without knowing the specific use case and circuits involved it isn't possible to say conclusively one way or the other.
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Post by 01235813 » Thu May 30, 2019 1:55 pm

tarandfeathers wrote:Also, generally speaking, you can connect pulse outputs together if they have series diodes, from memory this is not the case for any output on the 208. Other Buchla designs do have these diodes so you can stack multiple pulse outputs together.

CVs are a different situation all together, you're connecting (hopefully) low impedance outputs to (hopefully) high impedance inputs. The output with the highest drive capability will "win" and swamp the others, or the outputs will interact with each other. Depending on the design of the device driving the outputs this may or may not cause damage but without knowing the specific use case and circuits involved it isn't possible to say conclusively one way or the other.
Thanks for your reply. Many conflicting opinions.

I literally spent years busting my ass to save up for the easel. This was by no means something I bought on a whim. I've RTM many times (albeit, it was hard to follow before actually acquiring an easel) and spent a great deal of time trying to single out anything that could fry it.

I was thinking, it aught not be to easy to break the gadget whilst patching. If so, I would assume it would for sure be "common knowledge" amongst wigglers.

On a side note, I have utmost respect for those that were involved in the genre before internet, social media and whatnot. It's a really niche topic and I cannot imagine looking a beast of a 200e without some sort of reference aside from the manuals from Buchla.

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Post by Ginko » Thu May 30, 2019 5:50 pm

tarandfeathers wrote:
Ginko wrote:Regarding the OP, and as search isn't working, there is some rumour that 'circuit bending' the program card (using your fingers to bridge points on it in place of resistors, as demonstrated towards the end of a Charles Cohen video) can cause damage to the Easel. I have seen it suggested that this is down to the supply rails being broken out on the card, so you could apply an 'out of spec' voltage to somewhere you shouldn't. It has been suggested that cutting the traces for the supply rails on the PCB could protect against this.
This is not accurate. The resistance of your skin is pretty high even over a short distance, very little current is going to pass even across the maximum differential voltage of 30V. If you short across the power rails directly with a metal or other low resistance object you could cause the power supply to shut down (or damage it or the traces between it or the program card interface if the PSU design is poor).

The possibility of damage is due to the fact that there are pins on the program card interface that connect directly to CMOS devices with no additional protection against ESD. These days most devices have some protection built in but if you are charged up from walking across the carpet in your socks and you touch the wrong trace you could probably still zap something.
So basically it is a bad idea to do this in any case

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Post by mousegarden » Sun Jun 02, 2019 2:01 am

Am I right in saying that it's OK to mix and mult CV's in Eurorack through an un-buffered multiple, or stackables? I used to do this all the time with no ill effects. I'm doing the same thing with the Easel, if I couldn't do this it would get rid of one of the most important aspects of it! I feed the outputs of the Pulser, Sequencer, Randon etc etc regularly into oscillator CV inputs via staackables, and feed them back too, I'm more worried about feedback damage more than anything, audio especially, but everything's been fine so far.
And yes, you are connecting outputs to outputs this way, as some don't recomend, so where does that leave us?

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Post by Schrank » Sun Jun 02, 2019 4:20 am

mousegarden wrote:Am I right in saying that it's OK to mix and mult CV's in Eurorack through an un-buffered multiple, or stackables?
Mixing voltages with Stackcables or mults ist not a good idea.
When you're mixing voltages with a dedicated mixer module, the output won't get higher than +-12 volts. When you're using stacks for mixing tough, the voltages will just add up ad infinitum basically. Let's say you stack six 10v signals together you could have an output voltage of 60v which could harm your modules.
You are also connecting outputs together like this which is not the best thing to to either.

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Post by ndkent » Sun Jun 02, 2019 5:52 am

Basically professionally built instruments are expected to be used by new people learning. If you could do something yourself that damages itself you would see a warning "Don't do this--"

There have been a few situations where someone built something and later it was discovered that some combination might end badly. The manufacturer generally will fix it on a recall basis once discovered.

A topic that comes up often is running two or more signals into a single input. The common assumption is you are combining the two, so it's the same as a mix with no control... but nope, people who guessed they would get a mix may or may not be get that, electricity will not only go into the input but also back into the other output too, it's not one way. You might get a mix, you might get misbehavior from sending another voltage into an output. It shouldn't hurt the system, but conceivably you get higher voltages from some other device and the risk grows.

Okay - now a special Buchla ability not necessarily found in other gear. Buchla specifically built his system so triggers could be generated by several modules in a system and you can banana stack them into one input, the extra circuitry is there.

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