Hum....hm?

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AtomicPunk

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Hi Everyone,
First of all, this is my first post on the Warwick Forum as I just received my first Warwick bass! I picked up a Warwick Corvette 5 string bass in Nirvana Black.
Played it for a week at home between gigs and loved it! Ready to take it to the stage!
I usually play EBMM Bongo basses, which are humbuckers and dead quiet.
I plugged in the Warwick and there was a noticeable hum....I'm guessing due to the single coils. How have people dealt with the hum? Is there something I can do to reduce it?
Thanks in advance for your help!
 
I found some good information here, and I'm going to try shielding the cavity with some copper shielding material. It's a hum from fluorescent lighting, bad electrical, TV's, that kind of hum. I noticed it when I get it close to a TV.
 
James, I will certainly check that out, thank you...and thank you for the welcome, Florin!
 
AtomicPunk said:
Hi Everyone,
First of all, this is my first post on the Warwick Forum as I just received my first Warwick bass! I picked up a Warwick Corvette 5 string bass in Nirvana Black.
Played it for a week at home between gigs and loved it! Ready to take it to the stage!
I usually play EBMM Bongo basses, which are humbuckers and dead quiet.
I plugged in the Warwick and there was a noticeable hum....I'm guessing due to the single coils. How have people dealt with the hum? Is there something I can do to reduce it?
Thanks in advance for your help!
Click to expand...


Before ya do anything dreastic,although,I wouldnt call shielding drastic,ya should try to make sure it's the pickups that are making the noise.Does your amp have a ground lift switch?Or it could be a cable or powerboard your amp's plugged into.Some places are just plain noisey,& will make any single coil pickup hum,that no amount of axtra shielding can fix.
Hope ya get it sorted.Noise sucks.
 
It has done it in several different places when around TV's or dimmers or fluorescent lighting, so I'm pretty sure it is what I think it is.
The particular amps I have been using it thru (Yorkville Bassmaster XM 200) do not have a ground lift. I pretty much go straight into the amp without effects.
Shielding material on the way, will post results once I get it under way. Thanks, guys!
 
Pedro said:
What does the groundlift switch actually do?
Click to expand...

I'm no expert Pete,but the way I understand it is that it interupts any electrical "loop",that's been accidently created amongst the appliances that are plugged in & are running in a given building.Obviously,my explanation probably raises more questions than it has answered.:eek:Sorry buddy.
Someone paleeze explain ground lift without ballzing it up,like I just did.:confused::lol:
 
Well, applied the shielding to the cavity and under the pickups, no change. I hate to think I am going to either change out the pickups on a brand new bass to make it work for me, or just sell it. It's rather frustrating. Any other help?
 
I'm not 100% certain on this,but doesnt each shielded area need to be earthed as well to have any affect?
Each shielded cavity needs a ground wire running to the main earth in the electronics compartment.There's a cool dude here called Eberbachl(Luke)who does this mod to all his basses,as a general rule.He's into modding his basses & is very good at what he does.Might be a good idea to PM him to find out.
It's up to you if you change the picups or sell it,but a cheaper alternative might be to take it to a technician to make sure that it is actually the pickups that are making this irritating noise.
I have active single coil MEC pickups in my bass & it's very quiet,as was my Thumb which had the same pickups.
Are yours active or passive?All you've told us is that it's a Corvette 5.What actual model do you have?
 
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0.o everyone is so confusing, haha. I just move a little bit in any direction and the hum kind of goes away. Either that, or I pan to the middle where both pickups have equal volume. Remember, You won't hardly ever get hum as long as you have an even number of coils at the same volume ;)
 
I've got a Corvette 5 with MEC Passive Pickups (Dynamic Correction). Nirvana Black, if someone wants to make me an offer. Otherwise it is going back to the store tomorrow.

I've tried the pickup pan in the middle trick, didn't get the pickups to cancel the hum.

It's the reason I gave up on Strats when I was a guitar player, too much noise from extraneous sources like neon lights, bad electrical, TV's, fluorescent lights, etc.

Nice article on ground lift, too. A lot of amps I have owned in the past have had them and it did solve any hum problems. (Again, I was using passive single coil PU basses).
 
Pedro said:
What does the groundlift switch actually do?
Click to expand...

Hum is often caused by either a breach in shielding, or ground current. Ground current occurs between cable shield and earth ground, most often. The more ground current, the more hum. Ground lifting is intended to reduce ground current, thereby reducing hum. Ground lift places a resistor (usually around 100 Ohms) between the equipment ground and cable shield. This resitor limits the ground current passing in the ground loop situation, but still provides good ground connection (ground reference).

This method is unfortunately sensitive to radio interference, so the 100 Ohm resistor is usually shunted with small capacitor (often 4pF to 10 nF) which makes the impedance (to equipment ground) to be low at radio frequencies but does not allow much 60 Hz current to flow. Ground lift cannot eliminate all hum. It's always more effective to eliminate the source of the ground current.


I hope this helps,

Omar
 
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Thats very odd, i thought that passive basses were more resistant to hum than active ones. Guess I must be misinformed lol.
 
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