Double Bass Realist copperhead hum

[Sean Riddle]

While trying out some different settings with a Doubleshot combo I recently got, I noticed something odd about my Realist. It has a somewhat noticeable hum, almost like the hum from a passive bass guitar. While I know this pickup is passive, I’ve never noticed it before. Is it a sign that something needs to be fixed or is this a common thing and am only now noticing it due to a clear amp?

 

[KUNGfuSHERIFF]

How old is the pickup?

 

[Ric Vice]

It's possible that one of the two leads coming from inside the pickup housing is compromised. It's also possible that the combination of the Doubleshot with the Realist and wherever you're plugging it into the
wall isn't properly grounded. I've had this issue myself recently and had to get a Hum X Ground Fault Loop adaptor to remedy the hum. Does it hum regardless of wherever you plug it in or only in one spot? That's the key. Realists have a normal shelf life of around 4 years on some basses, where higher pressure is exerted on the bridge foot. Regardless, placing a pizeo pickup under the pressure of the under the bridge, will eventually cause it to degrade. There's really no way to know what's likely to be causing the hum, without playing detective and eliminating the possibilitles one at a time. Which is a PITA. It can be a bad wall socket, broken lead from the pickup, a bad wire inside the 1/4" Jack, or any number of things. You just have to be patient and work through all the possibilities.

 

[Sean Riddle]

How old is the pickup?

Only 2 years old, so should still have a few more years.

It's possible that one of the two leads coming from inside the pickup housing is compromised. It's also possible that the combination of the Doubleshot with the Realist and wherever you're plugging it into the
wall isn't properly grounded. I've had this issue myself recently and had to get a Hum X Ground Fault Loop adaptor to remedy the hum. Does it hum regardless of wherever you plug it in or only in one spot? That's the key.

It only hums with the Realist, not the Ischell I also have. I think you might be right about the wall not being properly grounded. I put my hand on a screw on the Clarus head and the hum stopped. Gonna be at a rehearsal tomorrow morning and will check to see if it’s still there.

 

[KUNGfuSHERIFF]

Bad power.

 

[Don Kasper]

Bad power.

I still carry this in my gig-bag to check the "power".
Thanks.

 

[Ric Vice]

Only 2 years old, so should still have a few more years.

It only hums with the Realist, not the Ischell I also have. I think you might be right about the wall not being properly grounded. I put my hand on a screw on the Clarus head and the hum stopped. Gonna be at a rehearsal tomorrow morning and will check to see if it’s still there.

You'd be amazed at how may wall sockets at rehearsal spaces and clubs aren't grounded properly or aren't grounded at all. Even some the outlets in my house were not grounded correctly, until I had an electrician come out and check them. Get yourself one of those ground fault detectors

like Don showed above. You'll be amazed at what you discover. Just because a wall outlet has 3 pins doesn't mean it's grounded. Sometimes the sockets are so loose from wear
that the plug doesn't make proper connections inside the socket.

 

[Chris Fitzgerald]

Doesn't the new Clarus have a ground lift switch on it, bottom right of the 4 lighted buttons? Or is that only a lift for the D.I. out?

 

[DoubleMIDI]

Doesn't the new Clarus have a ground lift switch on it, bottom right of the 4 lighted buttons? Or is that only a lift for the D.I. out?

I bet that is only for the D.I. out.
But there are cheap check devices for power outlets that include a ground check. Might be a good idea to get one and take it with the amp to rehearsals and gigs.
And it is strongly recommended not to isolate the ground, since that can be dangerous in case of a power short to the ground (metal object parts might have direct contact with power then).
For that you need an isolation transformer, but since that would be rather heavy, you might not want to carry it to every gig. (But if you go by car, it may stay there until really needed.)

 

[Sean Riddle]

Yup improperly grounded outlet is the culprit. At a rehearsal I was at this morning my Realist had no hum.

 

[unbrokenchain]

I still carry this in my gig-bag to check the "power".
Thanks.
View attachment 3705372

I love how the name of the device is only one letter off from "arson." If I had to guess for this case I'd say it's the first option (open ground). Old building? Maybe no separate ground, the ground on the outlet either is not wired at all, or shares the same line as neutral. Just a guess since my last house was like that until I rewired it and pounded in new ground rods.

 

[Ric Vice]

Cheapest fix ever, until you have to pay to have your domicile rewired. I ask one electrician to ground the outlet closest to the stereo system in my practice space, so he put a "ground fault detector" outlet in, not exactly what I wanted and the outlet still hummed.