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60 cycle hum


(@tinsmith)
Prominent Member
Joined: 17 years ago
Posts: 830
Topic starter  

Some one mentioned a "60 cycle hum" in one of the threads.
Is this the underlying reason, why just about ALL of my pedals, except 2, hum to beat the band.

Next big question.....how do you fix it?

I work with electrical engineers.....perhaps they have a fix that doesn't cost 8 million dollars.....I doubt it.

I wonder if it's because 50 cycles are imput to 60.


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(@anonymous)
Illustrious Member
Joined: 14 years ago
Posts: 8306
 

humbuckers, or sheilding your pickup cavity would cancel 60 cycle hum. if it's your pedals, they're probably noisy pedals or you have a ground problem.


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(@gnease)
Illustrious Member
Joined: 18 years ago
Posts: 5058
 

adding to what Jason has said:

pedal-induced hum is related to each pedal's power source and each pedal's power supply filtering: batteries usually = no hum for a pedal, as batteries inject zero hum (actually called supply ripple) into the pedal. when using an external supply, it's best NOT to go cheap, as pedals require a good quality supply that injects little of its own ripple into the pedal -- pedals are supposed to be able to filter out supply ripple, but how well is highly variable, so sometimes it's just better to "feed 'em nice, clean power. a good supply will have (a) low ripple and (b) sufficient current capacity (equal to or greater than the sum of all pedal current reqs) at the needed voltage (commonly 9VDC). the current capacity rating is critical, as asking too much of a power supply will lower the voltage and/or cause the supply to inject more noise and ripple into the pedals it is supplying.

there is also an issue of ground loops. these are redundant ground connections that cause susceptibility to hum and noise pickup in some audio systems -- mechanisms are several. sometimes, when two devices share ground connections through the signal path (1/4" interconnect cable's between in and out jacks) and also through having common power supplies, what are known as ground loop currents can flow in this loop or circuit, and these can be picked up in the audio path. the solution is usually to use completely separate supplies for the offending pedals -- whether battery or individual wall worts.

the test for the above problems is simple: run all pedals from batteries. if the hum improves or disappears completely, then then pedal powering scheme needs attention.

back to Jason's points: the prime source of electric guitar hum is usually the pickups (esp single coil) or the lack of proper shielding/quality wiring in the guitar. quick test: walk your guitar around the room with your guitar/pedal/amp setup "on". hum getting better and worse? then your guitar is the likely culprit. time to check its wiring, shield the cavity, maybe consider humbuckers.

one more thing… if you are a high gain player (e.g., metal, lotsa distortion and/or compression), you should probably be using a guitar with humbuckers or active pups.

-=tension & release=-


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(@anonymous)
Illustrious Member
Joined: 14 years ago
Posts: 8306
 

i knew you'd have a better answer than me


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