Back to p90s and noise reduction

[zionstrat]

Ok, we all debated ways to get quiet p90s in the past and I'm finishing a project where between heavy shielding and using 1 coil of a cool rail at a time for hum rection.

But we also know that this may run into the prime problems of using a dummy coil, ie, the resistiance is going to go up-

So one last question- has anyone considered tapped p90s as follows?

1. Tap both active pups for 4k and 8 k
2. build the dummy coil for 4k

Use the tapped coils when usign a single p90 and the dummy to get a total of 8k- Use the 8k tap when using the two p90s together-

Am I missing something or should I consider some customer p90s?

Looking forward to your input!
__________________
stock 83 Kramer Pacer Imperial for sale

 

[zionstrat]

Re: Back to p90s and noise reduction

Common guys- Someone's got an opinion and unless I'm missing something we haven't discussed this route?

 

[octavedoctor]

Re: Back to p90s and noise reduction

When ever you mix two coils you will get the two coils reacting with each other; there is no way of getting around that.

Fender used the idea of a noise cancelling coil in the Fender Elite but this was combined with an active interface which got around some of the impedance/reactance issues by providing a buffer circuit to isolate the coils and simply fed the inverted noise signal into the mix.

Bartolini also make 3-coil pickups in which you can switch between full humbucker and single coil with uncored coil.

The best way to do what you are trying to do is to make the noise cancelling coil (it's not a "dummy", it's doing something) the same as the pickup coil, then design a switch circuit that does this:

1)Neck pickup and /c coil aligned +>-
2)Neck pickup and bridge pickup
3)Bridge pickup and n/c coil aligned ->+

This will give you noise cancelling in all three position but the global impedance will remain the same

 

[tone4days]

Re: Back to p90s and noise reduction

interesting ... i have been wondering if the R&D guys at SD labs will apply the helmholtz voodoo of the classic stack plus to the P90 world with similar results

 

[octavedoctor]

Re: Back to p90s and noise reduction

The only switch that i can think of that will control this arrangement is a modular rotary with a 4 pole, 3 position wafer, although there may be an obscure 4 pole 3 way toggle that does the same thing.

The schematic of the rotary should look something like this:

 

[zionstrat]

Re: Back to p90s and noise reduction

Thanks octave doctor!
I think I'm going to try this with a 5 way super switch as I've already routed and will report back it I can ever get finished-

Thanks all

 

[octavedoctor]

Re: Back to p90s and noise reduction

If you are going to use the superswitch then you will have two redundant switch positions. I suggest going with this

This will allow you to compare the two solo p.90s with the equivalent sounds when the dummy coil is in circuit.

Unfortunately there aren't enough poles in the superswitch to allow you to have a series position (i think), which is a nice variant.

I let you know if I think of a way...

 

[zionstrat]

Re: Back to p90s and noise reduction

thx OD! But I've actually got 2 super switches next to each other and think there's going to be a way

Here's the original plan for use of the 2 switches using one with a cool rail, hoping that it would noise reject- So if this doesn't work, your ideas would come before I would try a stacked p90:

P90switch

Cool rail switch

Thx again for the input!