Joined: Feb 02, 2010 Posts: 266 Location: California
Posted: Thu May 13, 2010 4:07 pm Post subject:
Ajax wrote:
Top Top wrote:
Here it is with the LFO controlling the filter
Schematic for the filter? It sounds freaking great!
The filter is more or less Tim Escobedo's "Ghost Dance" which is this:
My only modification was to replace the .0015 cap with a .01 one because it got better filtering of bass frequencies that way. It is apparently a bandpass filter - it was designed as a wah for guitar, hence the lack of bass frequencies. I am still tweaking it a little bit - I was told that changing it so that both caps in the upper "T" were the same value would get more pronounced resonance... but in general I like the sound too.
Last night searching these forums, I found a schem by Hemo for an envelope follower made from 3 of the inverters on the 4069, so I am a little psyched about trying that out in combo with one of these filters to make an envelope following filter all out of one chip.
Joined: Feb 02, 2010 Posts: 266 Location: California
Posted: Sun May 16, 2010 2:36 am Post subject:
This thing is coming along...
I've come up with a home made switching solution to get any combo of the 7 oscillators to play on any step... working on the front panel right now... I'll show it to you when I've got it mounted - pretty fun...
One thing I want to add in is the ability to turn off the internal clock and then be able to step through the sequencer manually with a footswitch. I am thinking I can just wire the power supply to connect through an spst momentary footswitch to send a 12v pulse to the clock input when the switch is stomped... But I've noticed that the 4017 doesn't like an idle input - ie: it likes to be either grounded or receiving a signal or it seems to go a little wacky. Same with the oscillators... I've noticed that if you have no pulse hooked to the gates on the 4093, they can go crazy.
If I wired a (100k?) resistor to ground from the clock/gate inputs, might that help stabilize it when the input is idle, without needing complex switching to switch it to ground when the input isn't connected to anything?
Any other ideas on how to simply do this? (ie: if you notice I've wired up the circuit board already so preferably with no major additional electronics)
Here are my four breadboard oscillators taken into an 8 step pattern... starting to show some of the possibilities with playing more than one osc per step... I will be psyched to have those extra 3 oscillators with it once the whole thing is built.
And here we are with all the electronics soldered down on perf... no idea if I screwed anything up because I haven't tried it out yet... need to wire up the knobs... Thats a 4017, two 4093's, and the 4069 with the LFO and filter.
Joined: Feb 02, 2010 Posts: 266 Location: California
Posted: Sun May 16, 2010 10:50 pm Post subject:
Here's the front panel that I worked on today... it's not 100% together yet but I am pretty psyched with how it is turning out...
The pots are all placed but not wired. Those metal pieces are part of the switching system, but the holes around them still need screws and a few other things need to be put in place...
I will hopefully be able to have it together and with a demonstration of what's going on there within a couple days...
hello, I'm new to this site. I've been using it as a resource for building some cmos noise makers over the last week or two. i have a question relating to a project i am working on which is almost identical to this. my question concerns the inputs on the NAND, do BOTH inputs have to be tied to ground with a pull down resistor or is the one involved in the RC network taken care of by the capacitor. all of this is just starting to make some sense to me and it's thanks to the electro-music forums.
cheers guys
Joined: Feb 02, 2010 Posts: 266 Location: California
Posted: Wed May 26, 2010 3:56 pm Post subject:
Only the pin that you use as the gate input needs to have a pulldown resistor. The other two pins, the ones with the pot/resistor and capacitor, do not need one.
Also, the pulldown is only really necessary if you are going to have times when no gate source will be connected to the input. It is stabilized by the gate source connected to it.
thanks Top Top, that was an insanely quick response. yeah sometimes I will have the gate inputs un-connected, so pull-down resistors will be needed. thanks you
by the way, how is this project going? I'm intrigued about the switches
Joined: Feb 02, 2010 Posts: 266 Location: California
Posted: Wed May 26, 2010 4:10 pm Post subject:
It's finished. I posted in the "Let's see your Lunetta" thread. I guess I should have posted the final product in this thread too... as the rest of the progress was here...
Joined: Feb 02, 2010 Posts: 266 Location: California
Posted: Wed May 26, 2010 4:22 pm Post subject:
I should have maybe posted a couple of these other pictures too... here's what you're up against if you decide to wire something like this up.
The electronics design was the easiest part, IMO - the wiring of the front panel took FOREVER - that's 70 diodes attached to the back side of those switch poles (screws).
The electronics design was the easiest part, IMO - the wiring of the front panel took FOREVER.
Ah, the daunting task of making front panels. My two obsolete versions of meticulously crafted perspex frontpanels gathering dust are the reason I decided to restrict myself to "on circuitboard" Lunetta building for the time being.
Joined: Feb 02, 2010 Posts: 266 Location: California
Posted: Thu May 27, 2010 11:45 am Post subject:
electri-fire wrote:
Top Top wrote:
The electronics design was the easiest part, IMO - the wiring of the front panel took FOREVER.
Ah, the daunting task of making front panels. My two obsolete versions of meticulously crafted perspex frontpanels gathering dust are the reason I decided to restrict myself to "on circuitboard" Lunetta building for the time being.
If I wasn't using this in live performances with a bunch of other instruments, I would totally be with you there. It's all got to be pretty quick, fumble resistant, and uncomplicated for this particular purpose though...
I used it for two shows this week, by the way, and it worked wonderfully and got lots of questions of course.
Top Top - that machine is amazing! Simple as heck, but now with multiple oscillators running at the same time as well as the filter varying through time! That is just great sounding!
Wiring can be a bastard to do and a few times in the past, has caused me to pause from completing something for the moment. Most of the time at least, I have returned to and completed. But wiring, is the only thing that I'm not really a fan of, in my building.
A possible solution is PC mount pots. I've found though that with that solution, sticking with single sided PCB design, it's easier for me to just leave the pots on the front panel and wire them up, instead. (I usually have pots for almost anything in my designs / redesigns-modifications - hence the difficulty in proper PCB layout, via single sided PCBs.)
Joined: Feb 02, 2010 Posts: 266 Location: California
Posted: Fri May 28, 2010 3:43 pm Post subject:
andrewF wrote:
well done
its a great looking and sounding machine
yep wiring is the part that i always stop at, boxes of stuffed pcbs, panels ready to go....'just ' the wiring left
Generally I don't have that problem because I tend to get excited about finally using something and follow through on just one project until it is finished... In fact, I am a tad obsessive about finishing things once I have the vision of what it will be like. I have a very hard time working on something a little bit at a time, and want very much to be done and USE it.
Rykhaard wrote:
Top Top - that machine is amazing! Simple as heck, but now with multiple oscillators running at the same time as well as the filter varying through time! That is just great sounding!
Wiring can be a bastard to do and a few times in the past, has caused me to pause from completing something for the moment. Most of the time at least, I have returned to and completed. But wiring, is the only thing that I'm not really a fan of, in my building.
A possible solution is PC mount pots. I've found though that with that solution, sticking with single sided PCB design, it's easier for me to just leave the pots on the front panel and wire them up, instead. (I usually have pots for almost anything in my designs / redesigns-modifications - hence the difficulty in proper PCB layout, via single sided PCBs.)
Thanks, you are right, it is extremely simple -- the strength is in the the cool surprises that come out when you start dropping pieces on the steps in different combinations. Up to seven oscillators at one time can be pretty cool. My lady friend, who generally isn't that excited about stuff I build (bless her), thinks it is a load of fun and suggested that kids would really like to use it. I think there is something nice about having physical pieces that you can move around and instantly/very easily see/manipulate any step/any oscillator at any time.
I hear you there about panel wiring, but depending on the design, PC mount hardware isn't always an option. In this case, it would have been very difficult to keep the front panel design and still have PC mount pots. Also, I generally work on perf, so that is another whole aspect - have to make sure the PC mount pots can anchor to the board some way other than just with solder.
I don't really hate the wiring when I am doing it, but it just takes so LONG. Actually though, attaching those diodes and wiring them together was probably what took the longest, and it was sort of unavoidable given the design. Drilling 120 or so holes took a while too [/i]
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