Hum cancellation coils

[thinman]

Does anyone know of retrofitable hum cancellation coils?

The hum problems of single coil pickups are well known so why don't most now incorporate a hum cancellation coil like stingray pickups (and just about every microphone) does?

It made me wonder if someone has ever made coils that could be fitted to existing single coil pickups?

[brensabre79]

Some basses have a 'dummy coil' fitted, to reduce hum and interference. Its basically another pickup wired in series with the first but out of phase. It is possible, of course, but the reason not every bass has it is the same reason the Stratocaster guitars don't - the sound. Humbucking pickups by their nature also reduce some of the treble of the sound, so you get a more mellow, thicker tone. Not everyone wants this and many prefer the single coil sound as it can cut through a mix with much better attack. Even Musicman have switching options and single coil pickup configurations these days.

If you're experienceing extreme interference you could try checking and/or improving the screening of your bass. coating the pickup cavities with conductive paint, or copper tape and connecting to earth can get rid of huge amounts of hum and interference.

The Precision bass pickup is actually wired as a humbucker already so am I right to assume the issue is with your Jazz bass? If so shielding will definitely help alot. I have Wizards on my main Jazz (and an S-1) and covering the pickup and control covities in conductive tape made a huge difference.

If you really want humbuckers, you can get stacked humbuckers that fit in a Jazz bass pickup shape. DiMarzio do a few, as do other makes.

[iiipopes]

Actually, DiMarzio makes end-to-end coil J-bass pickups in their J and Ultrajazz models. I'm not sure, but I think their Area 51 models are the same construction.

Seymour Duncan makes stacks.

Fralin, Aguilar and Bartolini make end-to-end models.

Joe Barden makes rails J pickups.

I'm sure there are others out there. With all of these models, dummy coil technology and wiring is obsolete.

Edited December 12, 2012 by iiipopes

[thinman]

[quote name='brensabre79' timestamp='1355332226' post='1897089']
Some basses have a 'dummy coil' fitted, to reduce hum and interference. Its basically another pickup wired in series with the first but out of phase. It is possible, of course, but the reason not every bass has it is the same reason the Stratocaster guitars don't - the sound. Humbucking pickups by their nature also reduce some of the treble of the sound, so you get a more mellow, thicker tone. Not everyone wants this and many prefer the single coil sound as it can cut through a mix with much better attack. Even Musicman have switching options and single coil pickup configurations these days.

If you're experienceing extreme interference you could try checking and/or improving the screening of your bass. coating the pickup cavities with conductive paint, or copper tape and connecting to earth can get rid of huge amounts of hum and interference.

The Precision bass pickup is actually wired as a humbucker already so am I right to assume the issue is with your Jazz bass? If so shielding will definitely help alot. I have Wizards on my main Jazz (and an S-1) and covering the pickup and control covities in conductive tape made a huge difference.

If you really want humbuckers, you can get stacked humbuckers that fit in a Jazz bass pickup shape. DiMarzio do a few, as do other makes.
[/quote]

It was more of an idle thought - I too have Wizards (84s) and an S1 on my Jazz - hum's not a problem in standard Jazz configuration with both pickups up full.

I'm thinking of getting a Sterling and was reading about the hum cancellation coils fitted to their pick-ups and wondered why they're not used more often - probably for the reasons you explain.

[rmorris]

[quote name='brensabre79' timestamp='1355332226' post='1897089']

If you're experienceing extreme interference you could try checking and/or improving the screening of your bass. coating the pickup cavities with conductive paint, or copper tape and connecting to earth can get rid of huge amounts of hum and interference.

The Precision bass pickup is actually wired as a humbucker already so am I right to assume the issue is with your Jazz bass? If so shielding will definitely help alot. I have Wizards on my main Jazz (and an S-1) and covering the pickup and control covities in conductive tape made a huge difference.

[/quote]

Screening / shielding will reduce rf pickup which is higher frequencies. It cuts down the amount of interference which gets translated into noise at audio frequencies and should stop the local taxi firm coming through your amp and noise from computer monitors etc. But it won't do much to counteract noise from lower frequency sources - typically noise from transformers in amplifiers or from lighting rigs etc.
Technically it's because the interference is caused by an electromagnetic field. At higher frequencies the interference is predominantly electrical and shielding is effective. As the frequency decreases the field becomes more magnetic and normal shielding becomes less and less effective. The solution in an audio context is to use a low source impedance and impedance balanced wiring and electronics (as typical with microphones). Hi-Z pickups and single ended wiring and electronics mitigate against an ideal solution although the use of coil configurations discussed can help by cancelling out noise at the pickups.
With the correct pickup wiring options Hi-Z pickups (as well as low Z types ) can be configured as balanced sources and then the signal can be converted to a balanced low Z signal to send it down to the amp/fx. Basically wire the pickup as a balanced source and have a DI circuit in the bass.