I need some design help I am working on a guitar mod with 6 single coil ( 3 humbuckers) with every posible combination of serial and parallel with both positive and negative phasing. the coil cut switch used to remove a pickup from a series connection renders it unusable for simultaneous parallel use. the solution would seem to be splitting the signel at the pickup into two seperate channels each with it's own op am preamp'
Emg has dome this with the
The EMG Pi2 is an active phase reversal circuit mounted on a mini-toggle switch, and is used in guitars with two or more EMG Pickups.
Wired in series with one of the pickups, The Pi2 produces true "out of phase" sound by reversing the phase of the pickup. The active method of phase reversing is superior because it maintains the quietness of an EMG equipped instrument. It requires the same amount of space as a conventional phase switch, and only four solder connections are necessary. Along with the Pi2, mounting hardware and complete instructions are included to make installation easy.
EMG-Pi2 Package Contents:
EMG-Pi2 Switch
Output Jack
Battery Clip Set
EMG-Pi2 Quick Specs:
Output Noise (dBV) - -89
Output Impedance (Kohm) - 2
Current & 9V (Microamps) - 175 -
Battery Life (Hours) - 2850
Does anyone have a schematic for this or a quick sketchup of something similar that will work? I could also use some advice concerning op amp selection.
Any help would be hugely appreciated. a quick and dirty dip switch version is fine for now 2 6 pole dpdt dips for the phase reversal and two 6 pole spst dips should do the trick however I plan to eventually go to some sort of an analog switch mux or crosspoint and put the switching in a couple of foot switches IO have a bit of stuff that I did in isis that I can e mail anyone who is interested the files are a bit large for general posting.
Amplexus
Emg has dome this with the
The EMG Pi2 is an active phase reversal circuit mounted on a mini-toggle switch, and is used in guitars with two or more EMG Pickups.
Wired in series with one of the pickups, The Pi2 produces true "out of phase" sound by reversing the phase of the pickup. The active method of phase reversing is superior because it maintains the quietness of an EMG equipped instrument. It requires the same amount of space as a conventional phase switch, and only four solder connections are necessary. Along with the Pi2, mounting hardware and complete instructions are included to make installation easy.
EMG-Pi2 Package Contents:
EMG-Pi2 Switch
Output Jack
Battery Clip Set
EMG-Pi2 Quick Specs:
Output Noise (dBV) - -89
Output Impedance (Kohm) - 2
Current & 9V (Microamps) - 175 -
Battery Life (Hours) - 2850
Does anyone have a schematic for this or a quick sketchup of something similar that will work? I could also use some advice concerning op amp selection.
Any help would be hugely appreciated. a quick and dirty dip switch version is fine for now 2 6 pole dpdt dips for the phase reversal and two 6 pole spst dips should do the trick however I plan to eventually go to some sort of an analog switch mux or crosspoint and put the switching in a couple of foot switches IO have a bit of stuff that I did in isis that I can e mail anyone who is interested the files are a bit large for general posting.
Amplexus
I think youll have to focus your intentions a little. If i rembember right, there are 47 ways that are theoretically different in tone, to wire just three coils.
3 singles
3 pairs in series
3 pairs in series out of phase
3 pairs in parallel
3 pairs in parallel out of phase
4 All three in series, in phase or one out of phase
4 All three in parallel in or out of phase
3 x 4 series parallel in or out of phase
3x 4 parallel serirs in or out of phase
With 6 coils...it starts to get difficult!
But..if you accept that all coils that are on will be either all in parallel or all in series (no series parallel), you can do this with one two-pole switch to set each coil on or off, and a master switch with 2xn-2 poles. I can show you if wanted. With three coils this is a 4 pole switch With 6 coils, 10 poles would be needed. Not including phase switches.
My main point from all that is, it may be best to rationalise the design intent! Assuming a practical guitar is the intended outcome.
Also, most out of phase sounds are not so great. No need for too many if them.
I found with active circuits, that series or parallel wiring has quite a similar tone, just a loudness difference. This is because the guitar cord has much less tonal effect than in passive wiring.
3 singles
3 pairs in series
3 pairs in series out of phase
3 pairs in parallel
3 pairs in parallel out of phase
4 All three in series, in phase or one out of phase
4 All three in parallel in or out of phase
3 x 4 series parallel in or out of phase
3x 4 parallel serirs in or out of phase
With 6 coils...it starts to get difficult!
But..if you accept that all coils that are on will be either all in parallel or all in series (no series parallel), you can do this with one two-pole switch to set each coil on or off, and a master switch with 2xn-2 poles. I can show you if wanted. With three coils this is a 4 pole switch With 6 coils, 10 poles would be needed. Not including phase switches.
My main point from all that is, it may be best to rationalise the design intent! Assuming a practical guitar is the intended outcome.
Also, most out of phase sounds are not so great. No need for too many if them.
I found with active circuits, that series or parallel wiring has quite a similar tone, just a loudness difference. This is because the guitar cord has much less tonal effect than in passive wiring.
Hi, I would love to make an active EMG PI2 phase reversal module on a little piece of tagboard.I don't even
want it on a switch, just hardwired to my middle EMG S pickup in my strat. Can anybody help with this?
Hi,
Just reverse wire the middle pickup, it really is that simple.
rgds, sreten.
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Yes, I bumped an old thread.But I still want to make an EMG PI-2. It's not the same as just reversing the wires, the PI-2 has an opamp and there is much less volume difference between in/out of phase. It's a very useable out of phase tone.
I'm really not interested in ''all possible permutations of series parallel and phasing'', just one that works without drastically attenuating volume. The EMG PI-2 accomplishes this.
I wish I had a schematic of the circuit...
I did find this comment on another forum-
''The SA/SA/81 set are all active electronic pickups. These have a supply input lead, a signal/power common lead, and a signal output lead.
While internally "just" a two lead coil before the internal OP AMP circuit, these are not passive pickups and hence a DPDT switch cannot be of use in phase reversal.
The power supply input and signal/power common must remain the same for all pickups sharing the same power supply system/battery. This leaves the signal output lead for which there is nothing to switch it with.
As a result, an electronic means such as the PI2 must be used to invert (Phase Inverter 2) and not "reverse" the signal of an active pickup. This inversion results in an effect most similar to passive pickup phase reversal although there is no passive component interaction as there is with passive pickups.''
I'm really not interested in ''all possible permutations of series parallel and phasing'', just one that works without drastically attenuating volume. The EMG PI-2 accomplishes this.
I wish I had a schematic of the circuit...
I did find this comment on another forum-
''The SA/SA/81 set are all active electronic pickups. These have a supply input lead, a signal/power common lead, and a signal output lead.
While internally "just" a two lead coil before the internal OP AMP circuit, these are not passive pickups and hence a DPDT switch cannot be of use in phase reversal.
The power supply input and signal/power common must remain the same for all pickups sharing the same power supply system/battery. This leaves the signal output lead for which there is nothing to switch it with.
As a result, an electronic means such as the PI2 must be used to invert (Phase Inverter 2) and not "reverse" the signal of an active pickup. This inversion results in an effect most similar to passive pickup phase reversal although there is no passive component interaction as there is with passive pickups.''
An externally hosted image should be here but it was not working when we last tested it.
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