Hum is killing me. Wiring gurus, I need help!

[sawtooth]

Hi everyone,
Here I go.

Telecaster.
I'm installing a 'lil 59 in the bridge, a strat pickup in the middle, and a SD full size Seth Lover in the Neck. I got an E series Megaswitch (5 position) that will give me a lot of good combinations.

I wired it up like it says in the Megaswitch instructions but I get a hum out of all but the 'bridge only' position. I checked ground (used a meter for continuity) and it's all working. All the pickups work exactly as they should, but with this really bad hum.

Here's details for anyone who can see what my problem might be:
On the 2 humbuckers, I wired Black-hot, tied red and white together, and green=ground. On the strat pickup, I went 'White hot' and black to ground.

I didn't rewire the tone or volume pots, as the description about how they should be wired seemed to match. But...I noticed a resistor between the volume pot (pin 1) and the tone pot (pin 3) .

Anyway, I'm going crazy and I can't figure this out. Any and all help would be appreciated.

Thanks,
Arty

[BlueGuitar]

Re: Hum is killing me. Wiring gurus, I need help!

Hi everyone,
Here I go.

Telecaster.
I'm installing a 'lil 59 in the bridge, a strat pickup in the middle, and a SD full size Seth Lover in the Neck. I got an E series Megaswitch (5 position) that will give me a lot of good combinations.

I wired it up like it says in the Megaswitch instructions but I get a hum out of all but the 'bridge only' position. I checked ground (used a meter for continuity) and it's all working. All the pickups work exactly as they should, but with this really bad hum...

All I have on "E" Megaswitches is the picture in the Stew-Mac catalog- do you have it wired up like the second example: 12 3 45 - with 5 humcancelling settings?

When you say "really bad hum" do you mean something much worse than the normal hum you get from a single coil pickup? (When you rotate the guitar the hum doesn't go away - right?)

I'm asking all of these questions to clarify your problem- on one hand it is possible you are not using RWRP pairs of coils so the humcancelling effect is not working right. On the other hand there might be a bad ground wire that is causing the hum (in which case if you touch certain points with a grounded screwdriver the hum might go away- or get much worse! ).

As for the first issue- for a pair of coils to be humcancelling they must be of reverse polarity and of reverse winding direction. You can check the magnetic polarity of a pickup by aiming a compass at the top; if the needle is attracted to the pickup then the top of pickup has a North polarity. That might explain why the 3 middle positions have hum, but not position #1- for that you might want to make sure that the cable shield from the neck pickup is connected to ground.

It can be tricky connecting the coils of two humbuckers together so that humcancelling works; I sometimes have to flip a magnet and/or reverse all 4 leads to get it to work properly. Adding in a single coil pickup in the middle can make it even more complicated (especially if it is of the wrong polarity or winding direction).

HTH

[rspst14]

Re: Hum is killing me. Wiring gurus, I need help!

The bridge and neck should be the only positions that don't hum, unless you're doing some sort of coil splitting or special wiring. I'm not familiar enough with the Megaswitch to know the different possibilities, but if you're splitting the neck and bridge pickups at all, you'll want the middle pickup to be reverse polarity in order to get a hum-cancelling effect when combined with the split pickup.

Ryan