SpectralJulian
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« on: February 18, 2006, 10:24:32 AM » |
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I saw Zachary Vex's ringtone video and I got a little inspired. Plus I was drooling over what the moogerfooger ring mod could do. Realizing that I could add some jacks on the back of my EHX Frequency Analyzer, I figured I could make something very cool.
So, included in my plans for the EHX ring mod itself would be a CV-in, CV-out, and expression pedal jacks for the tune and mix knobs.
So, first question: would it be worth adding a square/triangle switch as well like the one colin did/how easy would that be? What is the added benefit sound wise of doing that?
Anyways, I want to build three eight stage sequencers like dnny's, put them in a box, and get some 3dpts and add a system to switch inbetween them.
Question 2- should I build a VCO in the sequencer box, or should I plug the sequencer box into the expression pedal jack? Plugging it into the expression pedal jack seems like it would be a little more tricky, but then it might be possible to power the sequencer from the voltage supplied there.
Last question: Dnny's schematic has a gate out. What is that for, and would I ever need it, or could I remove it?
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expanoncolin
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« Reply #1 on: February 18, 2006, 04:04:12 PM » |
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Sounds like fun.
Why add a tune expression pedal jack? You can just use the CV in and use a CV pedal to control the frequency.
Why build a second VCO? The sequencer could just control the VCO inside of the Frequency Analyzer.
The triangle/square switch makes the output signal sound buzzy and harsh instead of smooth. That's it.
The gate out is for starting ADSRs and that sort of thing, syncing stuff. You could use it in some way for fun but you don't need it as per what you described.
Good luck.
-Colin
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SpectralJulian
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« Reply #2 on: February 18, 2006, 08:12:05 PM » |
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I think I might have my definitions screwed up a bit, are carrier voltage and control voltage the same thing?
I thought of carrier as the 2nd audio signal- such as the tone being emitted by the VCO or some other audio signal- instrument, radio, tape, voice, etc. I think of control voltage as the output voltage of a variable resistor, so the control voltage tells the VCO what carrier voltage to output to make an audio signal.
If carrier and control voltage ins are the same thing, I could do your tutorial, add the jack, and hook it up to this (schematics and switch wiring diagram in attachments) and it would work?
Also, I don't know too much about the workings of a Frequency analyzer, what control voltage range would cover the frequency range that it normally uses?
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expanoncolin
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« Reply #3 on: February 19, 2006, 12:27:01 AM » |
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I think I might have my definitions screwed up a bit, are carrier voltage and control voltage the same thing?
I thought of carrier as the 2nd audio signal- such as the tone being emitted by the VCO or some other audio signal- instrument, radio, tape, voice, etc. I think of control voltage as the output voltage of a variable resistor, so the control voltage tells the VCO what carrier voltage to output to make an audio signal.
If carrier and control voltage ins are the same thing, I could do your tutorial, add the jack, and hook it up to this (schematics and switch wiring diagram in attachments) and it would work?
Also, I don't know too much about the workings of a Frequency analyzer, what control voltage range would cover the frequency range that it normally uses? In the case of ring modulators, I normally interchange control voltage with carrier, which is a bit of a mistake, you're right. The frequency analyzer's carrier oscillator is not voltage controlled, it's resistance controlled, but you could rig it up to be CV controlled, so I assumed that you mean carrier in/out. -Colin |
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SpectralJulian
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« Reply #4 on: February 19, 2006, 02:11:35 PM » |
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Yeah, I'd have to find out a bit more about how the VCO in the frequency analyzer works, and where I could patch in the CV to get it to control it.
I think just adding a carrier in like your tutorial says would be the best for me though, that way, I only make one modification to the Frequency Analyzer, and I can add a bunch of cool stuff to the sequencer. For example, I could put an LFO like the moogerfooger ringmod has in it.
Plus, I could hook it straight up to my amp and use it for other applications.
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expanoncolin
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« Reply #5 on: February 19, 2006, 02:57:15 PM » |
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Take a look at the 8038 datasheet. There is a fairly easy way to frequency modulate it built in.
-Colin
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SpectralJulian
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« Reply #6 on: February 19, 2006, 06:44:43 PM » |
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Yeah, I am just scared I'll accidentally break my frequency analyzer if I try to do to much to it.
Looking at the 8083 data-sheet and what it is capable, EHX really under-utilized a lot of stuff they put in there. They could have put on a switch to change the waveforms, added another switch to control the frequency range, etc. Lazy EHX. Well, atleas they don't charge up the arse for it like Moog does.
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expanoncolin
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« Reply #7 on: February 19, 2006, 10:48:27 PM » |
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I think EHX's goal was to make a fairly simple and straightforward ring mod, with definite musical uses that was not cheap at all... there are a ton of things they could have added, but it would have scared away a lot of users, pricewise and by the shear complexity it would add. Though I did talk to the guy who designed it and he was skeptical as to whether the square wave would sound much different (it certainly does).
-Colin
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SpectralJulian
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« Reply #8 on: March 03, 2006, 11:30:17 AM » |
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Ok, this projects going kind of slow as I don't have money for parts ATM, but I finally got around to opening the frequency analyzer and looking at the 8038 data sheet at the same time. Adding a switch to change from triangle to square to sine looks pretty easy, it looks like I just need to cut the line going from pin 2 to a capacitor then solder wires from 2, 3, and 9 to a 3 way switch all going to the capacitor.
I could also change the range of the VCO output by adding some capacitors that could be controlled by a switch.
I'm still not quite sure about where to put the control voltage in. It seems like I'll need to modify my sequencer schematic. I think I'd have to change all the pots in my schematic to be wired like so, and just use a switchable jack to cut off the shift pot and replace it with with the pots from the seq.
So I'd wire a switched jack up, send V+ ring, ground to jack, and the other wire to tip, hook that up with a stereo cord to the sequencer, the V+ would power the resistors and it would work similar to an expression pedal(might have to have a separate power supply for the 4017 and 4016, it depends on how much current the frequency analyzer already draws and how much my sequencer would draw)
Does that sound right?
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expanoncolin
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« Reply #9 on: March 03, 2006, 02:51:14 PM » |
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I'm not entirely clear on what you intend to do-are you going to have the sequencer be an external box, and you want it to be powered by the FA? Or do you want the sequencer to output a resistance, which will control the FA? Either way, putting 9v on ring and ground on sleeve is a bad idea-if you plug in a mono jack, you'd be shorting your power to ground.
-Colin
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SpectralJulian
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« Reply #10 on: March 03, 2006, 10:11:17 PM » |
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It would be a separate box feeding it a resistance.
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SpectralJulian
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« Reply #11 on: March 03, 2006, 10:34:13 PM » |
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EHX was kind enough to send me the schematics.
I think if I send the frequency analyzers power to the box via stereo, I don't think it would use too much of the current supply offered.
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expanoncolin
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« Reply #12 on: March 04, 2006, 01:08:14 AM » |
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EHX was kind enough to send me the schematics.
I think if I send the frequency analyzers power to the box via stereo, I don't think it would use too much of the current supply offered. It's not the current that's the problem, it's the fact that you could short the voltage to ground very easily by putting a mono plug in by mistake, or by simply having some sort of short between ring and sleeve. -Colin |
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SpectralJulian
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« Reply #13 on: March 04, 2006, 12:04:53 PM » |
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True. I guess the safest thing to do would be to build the power supply portion of the frequency analyzer into the sequencer box and daisy chain them. So then I could just use a mono 1/4" cord and just have ground and the resistance signal.
But isn't that a risk with any CV controller or expression pedal type device?
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expanoncolin
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« Reply #14 on: March 04, 2006, 03:43:26 PM » |
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True. I guess the safest thing to do would be to build the power supply portion of the frequency analyzer into the sequencer box and daisy chain them. So then I could just use a mono 1/4" cord and just have ground and the resistance signal.
But isn't that a risk with any CV controller or expression pedal type device? Most expression pedal inputs do not work as such, they are normally protected. -Colin |
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