PlanetZ forums - scopeusers.com

I was just wondering, i built my monomes, but flux, the other monome guy here has bought one
I see Jimmy "builds" by putting stuff together in a cool way, and maybe had to cut a fan hole or 2
Does anyone else build or modify stuff?

today i built a "where's the party at" board, its an 8 bit sampler,

previously i have built a few amplifiers and speakers, MIDIfied a speak and spell

I am working on my "planck" which is a guitar that works like the moog guitar but also has keys for each string
you can actuall "pluck" the string with a powerful electromagnet and key so you can get different attack envelopes with different amounts of "scrape" and so on, and sustain can be varied by holding the key at different pressure.
unpressed keys can electronically mute strings, and keys can be "locked" so you can forcibly mute strings when thay are not purposley played (good for crappy players like me!)

the onboard power is from a cordless drill battery, that way you can have 2 and quickly change it between songs once it starts to get low.
i hope to make it last longer than it takes to quick charge a battery it only will use a lot of power when the amplifiers have to do an attack, keeping sustain going hardly uses any power (my ebow still has only had the battery replaced 2 times i bought it 8 years ago)

signal processing will be designed in scope and once i get it how i want it, an actual onboard circuit will be built. (if i am still alive )

that thing is still in early stages, but its more than a dream now, thanks to scope

That's great Neutron.
I love DIY stuff. That sucker should do Melotron samples really well.
How about making a real analog filter to inject into Modular project windows?
I was told by the guy at MOTM that it was possible because of Scope's routings.
SFP's filters are great, but they can't seem to go down to the ground like the Filters on my analog synths have.
I would love to put filters like those into a Modular project. With all of the choices we have for Oscillators it would sound incredible...........maybe, I don't know.
I wish I knew how to build stuff.
Let us hear it when you get it working 100%.

actually thats another project, im waiting for a board i designed that can take a signal from scope and turn it in to a control voltage, i was going to use a great big version of the "draw anything" envelope from Roy thinnes (yes he helped me make a version)

it could be used to make new envelopes or LFO for your analog gear.

Make sure you let me know about this.
I would love to have real analog filters with the dozens of kick butt Oscillators we have.
IMHO the only thing missing other than analog filters, was seperate Oscillator glides, and that has been answered.

Once upon a time, I took stainless steel kitchen mixing bowls, manufactured rubber bushings with a grinder and sanding wheel and made a set electronic tom toms with a piece of sponge & a speaker to mimic the action of a piezo, like the old elec drums of the time...ie simmons, etc etc. that was the last attempt I made at anything requiring solder. But, it worked, I triggered various midi sounds & modules w/ them & thay worked pretty well. The acoustic properties sounded like roto toms.

The Scientist at work.
As a kid my Godfather was my Dentist, so I had access to those front surface mirrors that re direct light like a laser, well not really, but it lacks that blurry extra layer of glass that lays above the reflective surface.
At any rate I had an ancient Norma amplifier for my SG w/o a grill, so I took a rubber, seeings how I was a virgin, but a prepared one ( 14 years old ), and placed the rubber over the speaker. I then glued string from the rubber and ran it through the little holes I drilled on the round 2 inch dentist mirrors. When I played notes the mirrors would dance.
I then took our Christmas tree floodlight wheel ( remember those .. ) and faced the light onto the mirrors.
When I jammed in the dark the light wheel had those changing colors and I felt like I was playing in the band Iron Butterfly...
Damn, my room looked like a big acid trip.
That was the only good idea of anything I ever built, but we had Black Lights and posters and the wheel speaker thing and we thought we were Rock Gods.
Actually I have never matured as a person since then, I just play alot better.

I agree. The experience alone..making the rubber bushings, to attach the lugs, so the real drum heads & rim would attach, as well as the 1/4 inch plugs for the triggers, was the basis for my start in electronic percussion & I have not looked back. I actually made different sizes, 8", 10", 12" & 14". New Order was the inspiration.

http://www.youtube.com/watch?v=--pSWLEVGhY

Neutron wrote:actually thats another project, im waiting for a board i designed that can take a signal from scope and turn it in to a control voltage, i was going to use a great big version of the "draw anything" envelope from Roy thinnes (yes he helped me make a version)

it could be used to make new envelopes or LFO for your analog gear.

Hi Neutron,
Has this board anything to do with the Randy Jones MultiTouch Controller, which you mentioned in this topic http://forums.planetz.com/viewtopic.php?f=11&t=26620 under the heading Experimental Interface for Scope?
I watch your developments with avid interest and I'm inspired although my own creations are humble in comparison. I have built a midi drum project and I'm building a ucapps midibox project, which was something Jngaelin directed me to a while ago and I've got an Arduino board to play with.
I'm very interested in your Experimental Interface for Scope, is the board you are designing? If it is are you panning to sell? or impart this design? As you can tell, I'd be interested

no that experimental interface was a bit much for what you get, it needed 8 lines of audio I/O just for 1 controller, it seemed a bit of a waste. To avoid that it would have to have all the electronics built in, and i would rather spend the time and effort on some of my other unfinished projects.

The board i was talking about basically takes an audio output and changes it in to a control voltage for synths. it is really nothing more than a high speed envelope follower.

the reason you cant just connect a control signal directly to most outputs is because they are not DC coupled. so you have to modulate (in scope) high note with your control signal, which is "demodulated" by the circuit.

the actual control signal can just be whatever scope synth has the lfo or envelope you want to use to control your analog stuff. connect it to an output, connect the board to that output , and connect the output of the board to your analog synths control voltage input. then you play the scope synth to control the analog synth.

I would like a jpeg like Roland & UAD uses in their videos, with you in your white Scientist's coat while feverishly working on PCB's and circuits.
Some test tubes with boiling liquids, etc.

Studio mate build this with a buddy last week.
http://c4.ac-images.myspacecdn.com/imag ... 6100cf.jpg

This is good stuff, Neutron. I have a filter board sitting around for exactly this purpose.

I'm with you on the peak detection & lack of DC converters. There are of course the usual Midi -> CV converters, but...rather roll my own as well. Plus there's probably less lag going direct.

I wonder if there are any cheap D/A chips that'll do DC output?

Neutron wrote:no that experimental interface was a bit much for what you get, it needed 8 lines of audio I/O just for 1 controller, it seemed a bit of a waste. To avoid that it would have to have all the electronics built in, and i would rather spend the time and effort on some of my other unfinished projects.

The board i was talking about basically takes an audio output and changes it in to a control voltage for synths. it is really nothing more than a high speed envelope follower.

the reason you cant just connect a control signal directly to most outputs is because they are not DC coupled. so you have to modulate (in scope) high note with your control signal, which is "demodulated" by the circuit.

the actual control signal can just be whatever scope synth has the lfo or envelope you want to use to control your analog stuff. connect it to an output, connect the board to that output , and connect the output of the board to your analog synths control voltage input. then you play the scope synth to control the analog synth.

You're talking frequency to voltage conversion. The simplest is a diode pump, but there are a lot of IC's available.
Are you saying connect the analogue output from scope to the board which converts the frequency to a CV? That Scope output can have complex waveforms but you would just want a pure sine wave for f to V wouldn't you? Common CV (Roland) is logarithmic, 1v per octave (-5V to +5V), I believe. I know there are other CV schemes (Korg and Yamaha).

Eric.

no its not frequency to voltage thats too much hassle, its just AM.
the frequency "carries" the DC envelope past the blocking capacitors.
think of the normal output of a synth that only plays a high note (for envelope speed) then rectified.(in scope)

all it needs is a precision rectifier and a filter circuit to decode the envelope back to DC.
i might even be able to just get away with just a filter instead, then it could be bipolar.

Neutron wrote:no its not frequency to voltage thats too much hassle, its just AM.
the frequency "carries" the DC envelope past the blocking capacitors.
think of the normal output of a synth that only plays a high note (for envelope speed) then rectified.(in scope)

all it needs is a precision rectifier and a filter circuit to decode the envelope back to DC.
i might even be able to just get away with just a filter instead, then it could be bipolar.

Got it!

OK then in an am radio for example to "detect" the audio you just, as you say, rectify the signal and send through a low pass filter. This would not be bi-polar though.
You could also frequency modulate simultaneously and get 2 different envelopes on the same carrier, modem style.
The difference between modulating an audio frequency with a sub audible frequency (or DC) and modulating an RF carrier with audio, is the frequency differential between carrier and modulator. You have to rectify then filter. Filtering alone won't work. Consider 6db/octave and say a 2Hz modulator on a 15KHz carrier. That's about -78db carrier out. Remember DC is only DC when it doesn't change, so the envelope will have a frequency component proportional to the rate of change of the DC or the slope of the envelope.

Eric.

Just a side note. I'm working at it from a different angle, by modifying an existing D/A to do DC output. Conceptually, it involves removing blocking caps from an existing converter, and putting a servo op amp after that.

If all goes well, it'll be able to be multiplexed, meaning multiple analog outs from one digital input. However, a peak detect/envelope follower hung off an existing D/A stage is *much* simpler & cheaper to implement.

capacitor wrote:Just a side note. I'm working at it from a different angle, by modifying an existing D/A to do DC output. Conceptually, it involves removing blocking caps from an existing converter, and putting a servo op amp after that.

If all goes well, it'll be able to be multiplexed, meaning multiple analog outs from one digital input. However, a peak detect/envelope follower hung off an existing D/A stage is *much* simpler & cheaper to implement.

I just had a thought. Why not use a Scope digital output and process the digital signal to produce the envelope or whatever you want. I know it's not purist analogue but...
Isn't the ASIO interface digital audio? Just take the delta and you get the modulator. This could be done in a program running on the same computer. You would need an I/O board. This maybe http://www.compactpci-systems.com/produ ... /id/?37897 Just thinking aloud...

Eric.

To answer to the OP here's a list of projects I'm trying to complete:

• integrate a late '50s Hammond C3 tonewheel into Scope
  provide multiple channels of Scope-controlled CV to a set of analog Filter/VCA boards for a custom synth - we're talking 48 channels
  modify an old 88-key synth to provide poly aftertouch
  typical MidiBox stuff for reusing controls on a couple of old analog organs
  upgrade a couple of '70s Yamaha PM-2000 channel strips
  a bunch of custom tube amp work (power amps made out of old organ & tube tester chassis)

& a few others, but those are the main projects

Capacitor you gave me an idea, maybe i can get 4 or 8 control voltages from one channel by modulating several different frequencies with different controllers and then decoding them with bandpass filters