Jump to content
Why become a member? ×

Constant annoying hum/noise from (new) active ACG bass


Aero71
 Share

Recommended Posts

Recently bought a ACG Krell E bass here, [url="http://basschat.co.uk/topic/283592-sold-acg-krell-e-type-4-custom-bass/page__p__3033155#entry3033155"]http://basschat.co.u...55#entry3033155[/url]
and now I'm experiencing something I never had before with an active bass.

There is a contant hum/buzz/noise from the bass when playing through an amp.
It's like the noise you get from a single coil, but when I touch the string/bridge or tuners, the noise does not disappear.

When I tilt the body to a straight vertical position, the noise almost disappears, but tilting it a bit either way, the noise
is back.

I've checked the control cavity, everything is connection properly and correct. I've checked the ground wire underneath
the bridge, I've tried another power cable, another instrument cable, another power socket. Nothing...

Got other active basses, and the're all dead silent.

I love the bass, but the noise is irritating me.

Preamp is the ACG EQ01 with low pass filters instead of boost/cut.
Could it be the preamp?

Someone with other suggestions?
Hope someone can help me...

Edited by Aero71
Link to comment
Share on other sites

Did check the battery and replaced it, but no difference.

Taran the first owner didnt had this problem and he also asked Alan, but he said
try another amp or use it in a different part of the house.

I only have one amp, but since my other basses are dead silent, I doubt if it my amp.

Edited by Aero71
Link to comment
Share on other sites

The suggestion to try the bass else where was to see if the problem was specific to the location or if it was a constant irrespective of the location.
To check if the noise is being caused by the pre-amp do the following..

Disconnect the pickups from each filter board, screw terminals so no soldering required.
Then with a small piece of wire connect the hot and cold together on each filter board. This removes any input from the pre-amp then plug in the bass and if the there is no noise the pre-amp is not the problem.

Since you mentioned the noise goes away when you move the bass I am inclined to think the bass is picking up an external signal which Mr castle alluded to regarding dimmers.
Once had a bass with a constant ticking sound which took ages to work out, turned out it was an electric fence next to the house.

With no previous history of this problem with the bass either something in the bass has changed or something external is having an effect on the bass. As I mentioned if you want to send the bass back to be check over that is not problem but worth eliminating anything in situ if at all possible.

Link to comment
Share on other sites

There are two wires from each pickup going to the filter boards a green (cold) and red (hot).
Take the wires out of the screw terminals.
Take a piece of wire put it into the hot screw terminal and then into the cold screw terminal forming a loop. Do this for both pickup inputs.

Link to comment
Share on other sites

Has an earth connection come loose? Many (if not most) electric guitars have an earth wire running to the bridge so that when the player is touching the strings, s/he too is earthed and provides screening for the instrument. This is why touching the strings usually reduces or eliminates buzzing.

Link to comment
Share on other sites

I'm just wondering if there is space for the battery to move slightly when the bass is moved. If the battery connection or leads are dodgy or fractionally loose, that might do it. Try moving the battery when the bass is plugged in.

(My original thought was that it might be the keyboard player :D )

Edited by alyctes
Link to comment
Share on other sites

Unfortunately I don't have a precise ultra mini screwdriver at the moment, but I do notice the red (hot) wire is connected to the nr.2 connector of the filter board and the green (cold) wire is connected to the nr.3 connector, while the pdf file says nr.2 should be the cold connection and nr.3 should be the hot one.

Could that be the problem?

@alyctes: battery can't move at all, so that isn't it.

Edited by Aero71
Link to comment
Share on other sites

No that would be to sort a phase issue between the two pickups. You can however try it but I am fairly sure it will not be that that is causing any noise. Before you move anything make sure you take a picture of the wiring so it can be outback the way it was.

Have you tried the bass anywhere else to see if the problem is following the bass or if it is in one particular place. Does it still happen through headphones.

Edited by skelf
Link to comment
Share on other sites

Oh my, never believed this could happen but I did try it in another part of the house, and there is no noise problem.

In the living room (where old fasion not grounded power sockets are) the bass is dead silent, while in my man-cave (big attic) with
new wiring and new earth ground power sockets, this bass is making this noise/hum.
I really can't understand why...???

Well, the bass isn't the problem I guess. But do find it strange this is the only bass with this noise in my attic. No other basses
causes trouble. Mmmmm.... :blink:

Link to comment
Share on other sites

[quote name='Aero71' timestamp='1463236962' post='3049827']...in my man-cave (big attic) with
new wiring and new earth ground power sockets...
[/quote]

What other electric - electronic stuff is up there, or on the same level..? TV aerial amplifier..? Wi-Fi router..? Satellite dish..? Is there a neighbouring attic (if it's a semi-detached or terrace house...) with stuff in it (radio ham..? private disco..?). No street lights just outside, or mobile telephone masts..? Try unplugging everything possible; the culprit is there somewhere.

Link to comment
Share on other sites

I had a hum problem with basses and amps in part of the house. I was using home plugs (Internet through mains) and if I removed them the hum disappeared. They pollute the mains with noise that can be picked up on your bass or amp.

Link to comment
Share on other sites

Mmm, my bass amp is sitting next to an old '80s Luxman stereo amp, but I'm getting the noise also when the Luxman is turned off.
No neighbour attic, no disco, no light- or phone masts....
Could it be....the Luxman?

Link to comment
Share on other sites

[quote name='spyder' timestamp='1463237817' post='3049843']
I had a hum problem with basses and amps in part of the house. I was using home plugs (Internet through mains) and if I removed them the hum disappeared. They pollute the mains with noise that can be picked up on your bass or amp.
[/quote]

I had this too but only with one particular fuzz box!

Link to comment
Share on other sites

With a long lead plugged into the amp, hold the bass by the headstock and walk around the room, from corner to corner. Does the interference increase anywhere..? Look more closely around there if that's the case..?

Link to comment
Share on other sites

Your living room sockets must have earth/ground connection - does your man-cave stuff earth to the same point?
I would unplug (not switch off) everything in the place apart from the amp, and see if that sorted it - then plug stuff back in until the problem starts up again............

:)

Link to comment
Share on other sites

Well, I tried Dad3353's advice. Unplugged every device in my man-cave and walked around holding the headstock of the ACG. The hum is the strongest from where the amp and cab stands. The opposite corner almost no hum. From the spot where I usually play I'm receiving a lot of noise. Then I moved the amp and cab to that opposite corner and connected again. And again, the new spot where the amp and cab is, is nearly free of hum/noise. The opposite corner the most. Now from the same spot I usually play it's hum/noise free!!!

So I'm avoiding that (old) corner now. Do find it strange with everything unplugged. In the man-cave, which is on the 2nd floor, I do have earth/ground connection sockets. First- and ground floor don't have earth/ground connection sockets, but there's also no problem.

@JapanAxe: I use a sattelite dish, which is on the outside wall of the 1st floor, about 6 meters away from the problem spot. No extra amplifier, just a receiver on the ground floor.

Edited by Aero71
Link to comment
Share on other sites

Can you detect a heart-beat under the floorboards..? Did the previous tenant of the property suddenly become widowed..? :unsure:

There's something in the vicinity of the duff corner, either so visible you're not seeing it, or the other side of the wall or floor sending out spurious RF. If, by moving to the other corner, it's settled, then you're good to go, although it would be best, if possible, to go the whole hog and root out the cause. It may be source of future problems (I'm thinking here of a faulty earth or live connection, sparking gently, thus creating RF, and a possible fire hazard. Pure speculation, but a possibility...). :mellow:

Is it worse with the left or right foot forward, or the opposite..? :P

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...