Members Tomm Williams Posted July 13, 2016 Members Share Posted July 13, 2016 Lately I've been doing a great deal of experimentation with my pedal board and my various amps. I've discovered that some pedals sound much better through some amps if I flip phase on my Lehle Little Dual. In my attempts to keep things a little easier to get set, is there a footswitch that can flip phase? The button on the Lehle isn't that hard to press but a footswitch would certainly make things more convenient. Link to comment Share on other sites More sharing options...
Phil O'Keefe Posted July 13, 2016 Share Posted July 13, 2016 Lots of pedals invert phase, but that should only be an issue when you're running two amps in stereo, or are combining / mixing signals. I'm unaware of any pedals that are designed with the main purpose of inverting phase, although there are pedals with phase switches on them, such as your Little Dual. I think the Xotic X Blender has a phase switch on it too. You could look for a single stage boost or buffer that inverts phase and use that... that would probably be the cheapest "pedal" option. Or just swap the + and - wires on one of your amps / speaker cabinets. Link to comment Share on other sites More sharing options...
Phil O'Keefe Posted July 13, 2016 Share Posted July 13, 2016 I don't know why I didn't think of this one earlier... The Radial Engineering Bigshot ABY has a phase invert switch for one of the outputs. Added bonus: it also has an isolation transformer, which can be a big help in eliminating the ground loops and hum that are so common when running two amps at once. http://www.harmonycentral.com/news/t...igshot-in-town Link to comment Share on other sites More sharing options...
Members onelife Posted July 13, 2016 Members Share Posted July 13, 2016 One advantage to being able to quickly flip the phase is feedback reduction on an acoustic guitar with a bridge transducer. I was thinking it would be easy to build a phase switch into a pedal for a balanced line but not so much on an unbalanced without the use of a transformer. The Bigshot ABY seems to have addressed that - albeit in a box that requires a power supply. Link to comment Share on other sites More sharing options...
Members DeepEnd Posted July 13, 2016 Members Share Posted July 13, 2016 It shouldn't be hard to build your own. You could use a switch to reverse the wires. Link to comment Share on other sites More sharing options...
Phil O'Keefe Posted July 13, 2016 Share Posted July 13, 2016 I was thinking it would be easy to build a phase switch into a pedal for a balanced line but not so much on an unbalanced without the use of a transformer. The Bigshot ABY seems to have addressed that - albeit in a box that requires a power supply. I suspect, although I'm not certain that the power is just for the LED indicators. The pedal's switching is passive and true bypass according to the press release. Link to comment Share on other sites More sharing options...
Members onelife Posted July 13, 2016 Members Share Posted July 13, 2016 From the press release... "Should you experience hum and buzz problems due to ground loops, the BigShot ABY comes to the rescue with a built-in isolation transformer and ground lift switch. Once engaged, you can toggle the polarity of the second amplifier to ensure both amps play in absolute phase." It does use a transformer to enable phase switching so, in that case, it is not true bypass - but the transformer can be switched out when not needed (transformers are not necessarily bad things). From what I read, the power supply is indeed only for the LEDs. It looks like they've really got it all covered with this box - it's probably worth having one (or two) of them around just in case something comes up. Link to comment Share on other sites More sharing options...
Members DeepEnd Posted July 14, 2016 Members Share Posted July 14, 2016 You could do it with a DPDT push switch something like this: You'd also need an indicator of some kind to show when the phase was reversed: The indicator would be in parallel with the out-of-phase output. A series capacitor (not in the drawing) should keep the DC out of the signal. Might be a fun project if you're handy. I went with 9V simply because that's the standard for pedals. Let me know if you see anything wrong with the basic idea. Link to comment Share on other sites More sharing options...
Members onelife Posted July 14, 2016 Members Share Posted July 14, 2016 I can't read your diagrams - they come up blank. You mention a "series capacitor". Keep in mind that, although capacitors can block DC voltage, they do pass the transient that occurs when the voltage ramps up or down. This will result in a loud pop in the audio. It's best to keep the audio and the DC on separate circuits. Link to comment Share on other sites More sharing options...
Phil O'Keefe Posted July 14, 2016 Share Posted July 14, 2016 From the press release... "Should you experience hum and buzz problems due to ground loops' date=' the BigShot ABY comes to the rescue with a built-in isolation transformer and ground lift switch. Once engaged, you can toggle the polarity of the second amplifier to ensure both amps play in absolute phase."[/i'] It does use a transformer to enable phase switching so, in that case, it is not true bypass - but the transformer can be switched out when not needed (transformers are not necessarily bad things). From what I read, the power supply is indeed only for the LEDs. It looks like they've really got it all covered with this box - it's probably worth having one (or two) of them around just in case something comes up. If I'm not mistaken, the transformer comes after the switching circuit. It's independent of it, just as if you ran a separate iso transformer inline and in series from the Bigshot's B output jack. Same basic idea as using an TB ABY switch with a external transformer after one output, except the passive transformer is inside the same case as the passive ABY switch. Link to comment Share on other sites More sharing options...
Phil O'Keefe Posted July 14, 2016 Share Posted July 14, 2016 He probably is referring to classic DPDT phase switch wiring... Link to comment Share on other sites More sharing options...
Members DeepEnd Posted July 14, 2016 Members Share Posted July 14, 2016 Phil is pretty much correct. There's no diagram, just a pic of a switch and a diagram of an LED connected to a 9V battery with a series resistor. I figured the switching part was self-explanatory. Shows how much I know. Here's how it would work (the instructions are for a rocker switch but the principle is the same): http://www.instructables.com/id/HOW-TO%3a-Wire-a-DPDT-rocker-switch-for-reversing-po/?ALLSTEPS. The idea was to use the same switch for both phase switching and the indicator LED. Apparently it's not that simple. Link to comment Share on other sites More sharing options...
Members Danhedonia Posted July 17, 2016 Members Share Posted July 17, 2016 ^^^ This is correct. The Radial ABY is nice. Link to comment Share on other sites More sharing options...
Members onelife Posted July 17, 2016 Members Share Posted July 17, 2016 That standard DPDT phase reversal switch will not work with an unbalanced line where one side of the the input signal is tied to ground. Link to comment Share on other sites More sharing options...
Members DeepEnd Posted July 17, 2016 Members Share Posted July 17, 2016 Is there a switch that will? From your answer, I'm guessing not. You'd probably also need something like a dual switch (i.e., two switches in a single housing) to control the phase and indicator with separate circuits. Link to comment Share on other sites More sharing options...
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