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Iron Ether Subterranea
- Thread starter JBNeedsBeer
- Start date
I suspect that most pedals detect expression inputs using switched 1/4" TRS jacks:
With nothing inserted in jack, points where expression pedal goes in (tip, ring) are connected to the knobs on the pedal.
When TRS jack is inserted, the jack disconnects the knobs and looks at the pot in the expression pedal instead, or something like that.
It would also (depending on pedal/circuit) switch the control of a parameter to an isolated circuit that could re-use the pot/knob on pedal.
Connecting Ring and Tip as you suggest would only give the pedal the expression value of heel down (where the pot is at 0 resistance). Ring and Tip in an expression pedal are two ends of a variable resistance that you change by rocking the foot. Shorting them out just gives the minimum value, it wouldn't inform the pedal as to whether something is plugged in or not.
What you would have to do is bypass the jack switching mechanism altogether. Add a dpdt switch to the pedal, or outboard. Sound signal doesn't usually travel through an expression pedal signal... it simply provides a variable resistance that controls a parameter of the effect (I could be wrong on this). You could hijack the 4 connections + ground (poles 1 and 2, and the T and R of expression) and mount them on a DPDT you can control?
Or super simple.. depends. If it's near you could just hit it so that the expression's controlling something else...
clicky.. there. Unplugged.
Thanx for the explaination jjclr - it does make sense (we often see a trs jac). In that case I can bid my idea farewell since my pedals will remain behind my amp and I want to keep cables to a minimum (my next "hack" idea being to stick a Source Audio Hot Hand inside a wah enclosure for a wireless expression pedal)
Edit: But if the jack insertion only "makes" contacts, leaving the 2nd end of the TRS jack unplugged would create a theorically infinite resistance and therefore current wouldn't flow this way at all but throught the pedal's pots instead... so it must also "break" something. Either that or the XeroD would still function on "envelope".
By the way, the expressionator is not in a place I can easily switch it at all. Not that it matters given the above.
Edit: But if the jack insertion only "makes" contacts, leaving the 2nd end of the TRS jack unplugged would create a theorically infinite resistance and therefore current wouldn't flow this way at all but throught the pedal's pots instead... so it must also "break" something. Either that or the XeroD would still function on "envelope".
By the way, the expressionator is not in a place I can easily switch it at all. Not that it matters given the above.
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I think you misunderstand the way the pedal works. The expression pedal sweeps the frequency control, which sets the bottom frequency of the envelope's sweep. The envelope still works when you have an expression pedal attached unless you turn the sensitivity control all the way down. If you want a footswitch to change between manual sweeps and envelope sweeps, you will need to make a footswitch that effectively turns the Sensitivity control off.
Taylor Livingston
Commercial User
Sunbeast has it right. The expression jack is not switched, there is no sensing. The onboard Freq knob, expression pedal, and envelope all add together. To "turn off" the expression pedal, simply set the heel down - this is equivalent to not having an expression pedal plugged in. To turn off the envelope follower, set Sensitivity down all the way. Electronically one could add a jack to which you could connect an external footswitch to enable/disable sensitivity, but there isn't any place to actually put this jack as the XD is already maxed out in internal space.
oops! sorry for misinformation...
My experience with expression pedals (rainbow machine, qballs enigma, mothership) conforms with what I posted earlier, I'm conviced plugging in deactivated certain circuit features (pitch selection, envelope), but that's still my best guess without looking at schematics. No experience with xerograph yet...
No surprise the expression in xerograph is not switched (iron ether is just awesome)! Expression pedal "deactivated" by just rocking heel down. best of both worlds
My experience with expression pedals (rainbow machine, qballs enigma, mothership) conforms with what I posted earlier, I'm conviced plugging in deactivated certain circuit features (pitch selection, envelope), but that's still my best guess without looking at schematics. No experience with xerograph yet...
No surprise the expression in xerograph is not switched (iron ether is just awesome)! Expression pedal "deactivated" by just rocking heel down. best of both worlds
The cool thing about the expression on the Xerograph (and most filter pedals that have expression capabilities) is that it allows you to set the bottom reach of the expression sweep with the Frequency knob on the pedal rather than leaving a chunk of unuseable sub range on your expression sweep that you have to avoid. Then if you use a Moog expression or any other that has a knob to set the top range of the pedal, you can define the whole range of the sweep- very cool!
Ok, so my experience with the qballs enigma is an exception then... plugging in an expression pedal turns it into a wah, disabling the envelope control...
Controling envelope parameters with expression is cool! I hope this does not mean I need to acquire a filter with that functionality....
The way the expression pedal on the Enigma function with the Frequency control is the same as it is with the Xerograph, except that the Enigma has both a "Stop" and "Start" controls to set both ends of the sweep, where the Xero only has the "Start" (called Frequency). The Are you certain that the Expression bypasses the envelope function on the Enigma? Does the Sensitivity control do nothing when you have an expression pedal plugged in?
Yeah, the expression pedal controls the filter sweep motion in the enigma.
Start and stop determine the start and stop frequencies of the sweep as usual.
I'm not sure if the sensitivity knob changes anything other than the dirt when the second footswitch is engaged.
The sensitivity knob doubles as a gain/level for the added distortion on that second switch. When expression is plugged in, it only controls the dirt.
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I assumed other filter pedals operated in this manner...
The default assignment for expression inputs on the manta is similar, it controls the filter movement, usually assigned to input envelope.
Perhaps I overreached when I said "most filters with expression capabilities" functioned like the Xero- I've only owned filters with dedicated Frequency knobs, which the expression pedal essentially just piggy-backed off of as added resistance when plugged in, but there are lots of crazy different filters now with all sorts of added functionality (especially in the digital realm like the SA stuff). I'm used to having to manually turn the Sensitivity off for straight manual sweeps...
I did some Subterranea sound clips
Code:
https://soundcloud.com/kybu/sets/ironether-subterranea
oh whoa, oh, wow, oh wow.
It came in today. I can say my history with pedals has finally come full circle. From my first attempts to mimic Chris Wolstenholme's sound, as is the case with so many others in this forums (and thus first hearing about such things as a Big Muff and a synth pedal), through buying pretty much every type of drive, distortion, fuzz, filter and modulation (over 20 pedals bought over the course of 5+ years), becoming a fuzz addict and driving bandmates mad with my silly noises, I've finally got a synth pedal to suit the needs I had way back then.
I mean, the SubT can do a mean Muse-like sound, especially when combined with the Mastotron or Oxide. But it can do so much more. In ten minutes of fiddling around with the pedal, I've already got a couple ideas for new songs. It sounds absolutely delicious when coupled with the Xero Deluxe. And I still have to bust the Frantabit out of the box and try those two together.
So, yes, my friends. The day has come. I think I can finally be in peace with my gear. To be honest, I hadn't bought a pedal in over two years, but the SubT has always had a spot reserved for it in my board ever since I was first announced way back when, and I can say, after finally trying it out, it has not let me down, and is bound to become a permanent part of my set.
It came in today. I can say my history with pedals has finally come full circle. From my first attempts to mimic Chris Wolstenholme's sound, as is the case with so many others in this forums (and thus first hearing about such things as a Big Muff and a synth pedal), through buying pretty much every type of drive, distortion, fuzz, filter and modulation (over 20 pedals bought over the course of 5+ years), becoming a fuzz addict and driving bandmates mad with my silly noises, I've finally got a synth pedal to suit the needs I had way back then.
I mean, the SubT can do a mean Muse-like sound, especially when combined with the Mastotron or Oxide. But it can do so much more. In ten minutes of fiddling around with the pedal, I've already got a couple ideas for new songs. It sounds absolutely delicious when coupled with the Xero Deluxe. And I still have to bust the Frantabit out of the box and try those two together.
So, yes, my friends. The day has come. I think I can finally be in peace with my gear. To be honest, I hadn't bought a pedal in over two years, but the SubT has always had a spot reserved for it in my board ever since I was first announced way back when, and I can say, after finally trying it out, it has not let me down, and is bound to become a permanent part of my set.
