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Double Bass Grounding a mag pup?

E

EasilySpooked

Mar 14, 2012
11
1
MA
www.youtube.com
#1
Hello! I have only been playing about 18 months, just did my first string change and pup purchase, putting Eurosonic lights over a Krivo pup, run through an LR Baggs Venue DI into a JamHub studio.

Only problem is a ground hum. I'm sure it's a problem of space, plugged in in my basement which is notorious for such issues. I know it's a ground hum because when I make physical contact with the jack it ceases.

So my question for the more learn'ed and experienced, what can I do? I tried running a wire from the jack to the strings as one would with an electric guitar, but got no result, presumably for the poly wrap on the eurosonics.

If possible I'd like to achieve a clean signal, thanks for any advice and/or dopeslapping!
 
#2
First of all, magnetic pickups can be very susceptible to hum pickup. If you are in an electrically noisy environment, that may be the problem. Also, have you tried a different instrument cable of known quality? Don't assume your present cable is OK. Finally, does the hum stop when the bass is unplugged from the input of your Baggs DI?
 
#4
Doesn't seem that the Baggs Venue DI has a ground switch. Try plugging the Krivo into any DI with a ground switch. If it's still buzzing, simply flip the ground switch.
 
#6
thanks for the pointers!
The cables are good, brand new Planet Waves American Standards. The noise does go away only when I touch the jack, the pup itself is encased in wood. I had hoped to easily ground the jack to the strings by connecting it to the ball end of the strings, but that didn't work, since the strings are encased in plastic, so i'm not sure how to go about initiating the ground.

The DI doesn't have a ground switch, and the problem also occurs when placed straight into an amplifier.

I am in an electrically noisy spot, but I'm hopeful that with perseverance and a little help I can overcome the hum.

Basically I know I need to ground, but I'm not sure how to do so. If I can't, what would shielding the electronics involve? I know a bit of how to do it on a solidbody instrument, but not with the freefloating pup and wires on an upright.

Again, thank you for your time and expertise!
 
#8
I'd exchange for a new pickup...maybe this unit has been dropped or damaged somehow. The impact of dropping these these can damage the internal shielding. This kind of pickup is designed to be "noise free" without any extra external grounding, if it's loudly buzzing, it is damaged....

Did you buy it used?
 
#10
Hm, thanks I'll take it up with the distributor as I did buy it new. It's a new Krivo pup, claims it's a humbucker, tends to get solid reviews, I like the sound well enough, though the Eurosonics are a bit lackluster going from the warm thick tones of the Helicore Pitzicattos that came on the bass (very very used korean made)

Again thank you, i look forward to doing a bit of lurking and learning, seems like a good forum
 
#11
If the strings are plastic coated, then grounding them will have no effect, as they will have no conductivity to your body when you touch them. If touching the jack makes the hum go away, then take a wire from the the jack to an earth ground, or - rather unorthodox - attach it to your body somehow. Solder the end of the wire to a penny and stick it in your pants?:eyebrow:
Some mag pickups just hum because of how they're made. Doesn't mean they're defective.
 
#12
the Krivo is similar to the old the Sunrise acoustic guitar pickup in that it is designed to be hum free without the ground wire used by most traditional magnetic pickups systems. my experience with this kind of pickup is that there can still be some slight buzzing in some situations, or worse if the unit is defective somehow.

it looks like the *gullahar* music sells the Krivo/Eurosonic combo often, so i'd assume that a ground wire should not be neccassary under most normal playing circumstances
 
#13
While humbucking pickups are usually able to reject 60-cycle hum fairly well, that doesn't necessarily mean they can reject electrical noise, which usually manifests itself as a buzz. This comes from electrical equipment such as light dimmers, florescent lighting, appliances, motors, computers, etc. Poor electrical wiring in a building can also be a contributing factor. (Since many of us refer to any electrical noise as hum, it can be hard to differentiate between hum and buzz just from a description.)
 
#16
The pickup is fine. The cords are fine. The jack is fine. What is not fine is that it still needs grounding to the strings, just like the bridge of an electric bass. Try taking copper foil, the kind that stained glass folks use, and running a small strip from each string bridge notch to a common grounding point on the bridge, then from the bridge to the ground lug of the jack. I think you will see that, just like on an electric bass, all noise issues go away with regular playing. The Krivo, being a humbucker, is really just another version, electrically speaking, of a Precision Bass pickup.
 
#19
MR PC said:
illipopes, that won't work as long as he's using those snythetic coated Eurosonic strings.
Click to expand...
I did not understand these were the strings the OP was considering. In that case, then the pickup itself won't work as well, either. If those are the strings the OP is considering, then to make sure the pickup is efficient and noise is dealt with, then steel, or at least steel wrap, strings should be used. I believe if the manufacturer is contacted, that the recommendation will be for steel or steel-wrapped strings.

A player must take the time to understand exactly what is involved when fitting what is basically (pun intended) an electric bass pickup to a double bass. It needs to be wired like an electric bass with steel or at least steel wrap strings and proper grounding of the pickup to work.

This is in complete contrast to any pressure-based pickup, which the piezoelectric effect induces the electrical signal instead of electromagnetic inductance, and therefore is wired differently.

The issues involved with string grounding, including, believe it or not, shock hazards, as well as ease of installation, ability to use any string type, and avoidance of having to do significant modifications to the instrument, are reasons I fitted a Full Circle to my bass instead of something like a Krivo, even after over 35 years of wiring electric instruments.
 
#20
EasilySpooked said:
Unfortunately i've contacted Gollihur twice and gotten no response.
Click to expand...

Sorry, just couldn't leave this hanging out there...

Just to update, I had replied to both of your emails personally... and later in the day yesterday (5/9) you received and replied to the second response.

Let me know if Jason at Krivo helps you out (or doesn't).
 

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