Aguilar OPB3 doubles as a radio, help!

[GeneralElectric]

Just installed an aguilar OPB3 preamp into my Stingray 4H. I just wired it up and I'm getting some ground hum and, if I touch the control plate, radio signals! I haven't put strings on it yet, but I don't think that should affect things. Help!

Controls are

Volume
Treble
Mid (p/p)
Bass

I followed this wiring diagram
vpp-t--mpp-b.pdf

With the exception of the volume pot where I wired the green wire straight to the primary lead of the output jack. The battery box is wired to the ring. The black wire from the preamp (going to assume this is a ground) and the bridge are both on output jack ground.

There is no additional shielding done to this bass and none of my solder joints are cold. HELP!

 

[vindibona1]

Perhaps you need to add copper shielding to the cavities.

 

[ABtheBassPlayer]

There is no additional shielding done to this bass and none of my solder joints are cold. HELP!

Yes black is ground.

I agree with @vindibona1 , you should add some copper tape or aluminum whichever you have on hand.

 

[DiabolusInMusic]

Just installed an aguilar OPB3 preamp into my Stingray 4H. I just wired it up and I'm getting some ground hum and, if I touch the control plate, radio signals! I haven't put strings on it yet, but I don't think that should affect things. Help!

Controls are

Volume
Treble
Mid (p/p)
Bass

I followed this wiring diagram
vpp-t--mpp-b.pdf

With the exception of the volume pot where I wired the green wire straight to the primary lead of the output jack. The battery box is wired to the ring. The black wire from the preamp (going to assume this is a ground) and the bridge are both on output jack ground.

There is no additional shielding done to this bass and none of my solder joints are cold. HELP!

If the noise stops when you touch metal/strings/bridge, that points to RF interference and shielding. If the noise gets louder when you touch metal, it points to a grounding issue.

 

[GeneralElectric]

I spoke with Aguilar. I'm going to C&P their email to me here since I've seen other reports of this online but they've pretty light on solutions. Also! Big shout out to the guys at Aguilar as always. They got back to me in the same day!

I haven't had a chance to do anything yet, but maybe this weekend.

From what you are describing here, let’s try the suggestions below for grounding as well as RF interference:





Grounding Tips:



Grounding is not shown in our diagrams because it can vary from installation to installation.



If you do not have a specific ground configuration in mind, I recommend that you do the following:



1. Ground the backs of all the pots

2. Ground the shields and ground wires from the pickups

3. Ground the strings/bridge of the bass



How you do this is up to you. If it were my bass I would do as follows:



1. Connect the black wire from the OBP to the sleeve terminal of the jack

2. Connect a bus wire across the backs of all the pots and run the end to the sleeve terminal of the jack.

3. Connect the shields and grounds from the pickups to the backs of the volume or blend pots, or to the bus wire.

4. Connect the cavity shield to the bus wire





RF interference Tips:



1. If the input jack is dirty or not making good contact when connecting the batteries.

2. Are the pot bodies grounded? If no, then ground them, if yes, then un-ground them.

3. Is the cavity shielded? Is the shield grounded?

4. Do you have a solid connection to the strings of the bass?

5. Dirty or contaminated connections can sometimes cause a connection to behave like a diode. And in the radio world a diode is called an "AM detector"!





This should help out here but let me know if I may assist further.



Kind regards,

--Marco

 

[Clark Dark]

Is it possible for you to post a pic of your wiring of the circuit? I ask because you say you wired the green wire directly to the output jack but it's supposed to go to the volume pot. That scheme is for the use of an active passive switch. If possible post a pic.

 

[GeneralElectric]

Is it possible for you to post a pic of your wiring of the circuit? I ask because you say you wired the green wire directly to the output jack but it's supposed to go to the volume pot. That scheme is for the use of an active passive switch. If possible post a pic.

I used the one linked already and "this" one. In all their diagrams where there is no push/pull volume pot, and just a normal, their green wire is wired to the output jack.

v-t-msw-b.pdf

Still haven't had time to finish this.

 

[Clark Dark]

Ok, the first scheme that appears to be provided by BBG shows the green wire going into a six lug switch, not the output jack. Have you grounded all the pots? You can ground the backs of all the pots.

 

[GeneralElectric]

Ok, the first scheme that appears to be provided by BBG shows the green wire going into a six lug switch, not the output jack. Have you grounded all the pots? You can ground the backs of all the pots.

My next step is grounding all the pots together. Unfortunately I haven't had an off day in sometime (currently have 40 hours OT this week and its only Wednesday!) so I HOPE

Am I correct in assuming that I run a ground wire from the back of each pot and linking them all together? Do I think connect that to the ground on the output jack? I haven't shielded the control cavity yet either, but I'm out of copper tape.

 

[Clark Dark]

Yes, you ground the backs of all the pots and use one of them as a point for grounding the bridge. On the output jack there should be the negative 9V, the black wire from the pre which will include a ground from the pot(s) and the green wire from the pre.