A question for P-Eail Gurus: Can you "Dummy-Coil" a P-Rail?

DoronEsh

DoronEsh

New member
Hi

This is just a thought: I have a Gibson BluesHawk that uses a dummy coil to cancel hum for its two P90s. It's engaged when either bridge or neck pup is selected on its own, and off when both are on, as its hum canceling is no longer needed.

I have installed a set of P-Rails on one of my guitars, and its sound great. It's not a noisy guitar, but still, it hums when in single-coil mode (either Rails or P90s mode). Since there's always a spare pup (P90s are off when Rails are on and vice versa), the question is if there is a way to wire that guitar in such a way so that the pup not used for sound is used for hum canceling purposes.(*)

Any ideas?

DoDo

(*) I'm looking for a way for each pup to "dummy-coil" itself (bridge P90 to bridge Rail, neck P90 to neck Rail)
 
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Re: A question for P-Eail Gurus: Can you "Dummy-Coil" a P-Rail?

Within each indiviadual pickup, partial hum-cancelling ought to be possible. If you engage approximately half of the resistance value of the "unwanted" coil, this would provide partial hum cancellation for the "wanted" coil.

The switching required to achieve this would put rather a lot of brown stuff between your pickups and your output socket. IMO, this is not massively desirable.

Another option is to control your P-Rails coil balance via a stacked pot - as found on many two pickup bass guitars. Again, this may introduce too much brown stuff into your signal chain.
 
Re: A question for P-Eail Gurus: Can you "Dummy-Coil" a P-Rail?

The short answer is no.

As soon as you try to use another coil, it will be on and you'll get in-between tones. Now these would be fine usable tones but not a dummy coil affecting a single coil on the other pickup.

People have often asked about dummy coils here, and the consensus is that they affect the tone in a negative way because you are introducing a bunch of added wire. The Blueshawk is an exception -it was designed that way from the ground up and it's arguably not a pure P90 tone. In essence, a dummy coil has to have NO magnetic field in it to work and it only picks up the ambient noise, not the vibration of the strings.
 
Re: A question for P-Eail Gurus: Can you "Dummy-Coil" a P-Rail?

I know that the BH's dummy coil has got no mag, but AFAIK split HB's were used before to dummy-coil each other in single mode, and it was done without the tone loss. How to do THAT is the big question. Can you engage the "silent" coil so that its output goes only to the ground, and thus does not effect guitar sound, yet bucks hum? Ideas ?
 
Re: A question for P-Eail Gurus: Can you "Dummy-Coil" a P-Rail?

You can dummy-coil all pickups. Just buy a second one and put it somewhere away from the strings and/or remove the magnets. If it is reverse wound you get hum-canceling.

Of course you still get the changes in capacitance, inductance and resistance from doing so.
 
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