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Double Bass Electrical Issues

B

Bruce Calin

Supporting Member
Oct 15, 2002
1,723
3,043
#1
I have recently had an issue with the quality of electricity at certain venues. I can't use the rig I use tonight on a gig tomorrow because I will have major buzz problems at this other club. The one amp does it, the other one I use doesn't. The weird thing is I can't use the second one at the first place! The guitar player has a similar problem. We tried a power conditioner, which didn't do anything. Has anyone had this problem, and if so what did you do? For all of the disadvantages, the all acoustic days were definitely simpler.
 
#5
I assume it happens just with the amp into the power outlet and instrument into your amp. No other connections like DI to the board or other things connected that use a power outlet.

I‘m not sure what your power conditioner does exactly.

Have you tried a 1:1 transformer to galvanically separate power outlet from amp? Maybe together with an inline coil (don‘t know the common name for it) to suppress spikes.

If it is a problem that happens in conjunction with the board, a ground lift should help, unless some really bad installation was done at the venue or a device is damaged.

In the end it is a problem of both venues and not your task to solve it.
Talk to the house technician, that it is a problem of the venue, not your amp and that they need to solve it rather quickly.
You can explain that your amp works without problems at other venues.

If you need money to invest to solve it, somebody else needs to pay what it needs to solve it. So if the venue needs to pay, they may solve the problem quicker …
As far as I see it, each venue has to pay half of the amp that does work there.

There is a very small probability, that your amp is not well shielded to (some kind or frequency of) electrical noise.
In that case the house technician needs to shut down power (not yours of course) and shut off unneeded devices until the culprit is found. If possible do this on a different day than your gig or get there with the technician two hours earlier to check it.
 
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#7
All good suggestions There is no FOH. The idea that these small venues would be helpful is pretty remote. It's just a fact of gigging life in these circumstances so we learn to deal with it. The music is still the most important. The thing that's surprising to me is that these power conditioners(supposedly good brands) are so worthless.
 
#11
Bruce Calin said:
I have recently had an issue with the quality of electricity at certain venues. I can't use the rig I use tonight on a gig tomorrow because I will have major buzz problems at this other club. The one amp does it, the other one I use doesn't. The weird thing is I can't use the second one at the first place! The guitar player has a similar problem. We tried a power conditioner, which didn't do anything. Has anyone had this problem, and if so what did you do? For all of the disadvantages, the all acoustic days were definitely simpler.
Click to expand...

Yes it's not unusual, and I agree it's a frustrating mystery.

I have a fairly large collection of amps. I have sort of random noise problems with the Aguilar DB359. It was picking up AM talk radio and also it tends to have sort of a wiry buzz that develops in the preamp or tone stack.

I am not sure if the amp has a fault or it's due to the wiring in my house. I found that if I lift the AC ground, both problems disappeared. Unfortunately it's not considered safe to lift the ground, so not a solution.

Awhile back I adjusted the phase inverter in the amp and it seemed to reduce the buzz a bit and I have not heard AM radio in the amp since. Could be a coincidence though. The level of buzz is still somewhat irritating and it varies. Sometimes I can barely hear it and other times it becomes loud enough to be bothersome. The changing hum levels, makes troubleshooting more complicated.

I am retired from gigging, so I have not tried the amp in other buildings. I have tried it on other plugs in my basement, and the problem was the same. It was upstairs when I did the phase inverter adjustment, and the noise seemed pretty. But it's possible it was during a time of the day when the problem is less severe.

Too much hassle to take the amp upstairs, as it has a Mesa D180 sitting on top of it.

I also noticed AM radio coming through my pedal board with one of my other amps. I don't remember which, but I tracked it down to one specific pedal. Disconnect the pedal and no more radio...but this pedal is fine with my other amps.

I think an Ebtech Hum X would cure the noise with my DB359. The Hum X essentially lifts the chassis ground unless there is a fault. To do this it puts a pair of fairly large antiparallel diodes inline with the AC ground connection.
upload_2023-7-21_14-49-17.png


As long as the voltage across the diodes is less than 0.6V, the diodes do not conduct; so the ground is essentially lifted. If there is a fault, the voltage goes above 0.6V and the diodes conduct, thus connecting the ground. Hopefully the fuse blows before the diodes...otherwise you could get 120V AC on the chassis.

Unfortunately the amp is fused at 7 amps and the Hum X is only rated for 6 Amps. Meaning the diodes would probably fry before the fuse.

AFAIK this device is not UL listed...so they are not safety certified.
 
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#12
I know so little about the actual electronics of the various amps that I don't know what I don't know but one is much older than the other and maybe that has something to do with it. I'll ask the guitarist if his amps are much different ages. I'll also pay attention to any problems other places. So far I'm only aware of these two. Lights don't seem to do it, and least not for both amps at the same venue. They're very venue specific.
 
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#14
longfinger said:
Could be the lights?

I'm curious, tonight+tomorrow, could you please try rotating/pivoting your amp on the floor, slowly, to 90º then all the way 180º? Any changes in buzz?
I'm curious if the Earth's magnetic field could be causing some buzzing. This works with buzzing bass guitar magnetic pickups, maybe it could work with an amp?
Click to expand...
We tried this with the guitar and his amp. It actually got worse in some positions but couldn't be reduced beyond a certain point.
 
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#17
I occasionally had these problems with venues when I was touring often. The eb hum eliminator always took care of it. I have no idea what it does or why it works. I do know that whenever it happened the venue always blamed my gear which seemed kind of silly because often I had no issues the night before in a different venue... it seemed expensive when I got it but it has definitely been a useful tool over the years.
 
#19
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