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Problems with my Aguilar OBP-3

jive1

jive1

Commercial User
Jan 16, 2003
12,525
4,060
55
Alexandria,VA
www.jivesound.com
Disclosures
Owner/Retailer: Jive Sound
#1
I have an Aguilar OBP-3 that I had as an outboard unit, and it worked fine. Yesterday, I decided to install it into a bass. After everything was connected, and installed it had problems.

When the midrange pot, or treble pot is moved away from center I get a loud hissing noise. It's a steady hiss, similar to the sound of the TV when it is not receiving a channel. Everything is connected properly, and I checked and double checked. The jack is fine, as well as the volume pot and pickups. When the preamp is bypassed, everything works fine.

Any ideas?
 
#2
jive1 said:
I have an Aguilar OBP-3 that I had as an outboard unit, and it worked fine. Yesterday, I decided to install it into a bass. After everything was connected, and installed it had problems.

When the midrange pot, or treble pot is moved away from center I get a loud hissing noise. It's a steady hiss, similar to the sound of the TV when it is not receiving a channel. Everything is connected properly, and I checked and double checked. The jack is fine, as well as the volume pot and pickups. When the preamp is bypassed, everything works fine.

Any ideas?
Click to expand...

FWIW:

sounds weird. A bit lame to mention I suppose but I guess you checked the onboard version against the Aggie diagram, running it outboard requires a different wiring scheme to handle two jacks. If it worked fine as an outboard, then that essentially demonstrates the preamp is fine and the wiring is amiss given the same pots were transfered to the bass.
 
#3
The change from outboard to on-board was minimal, and I actually rewired the thing again and double checked against the wiring diagram from Aguilar.

Aguilar tech support thinks it's a damaged pot, so I'll check when I get some new ones.
 
#5
jive1 said:
The change from outboard to on-board was minimal, and I actually rewired the thing again and double checked against the wiring diagram from Aguilar.

Aguilar tech support thinks it's a damaged pot, so I'll check when I get some new ones.
Click to expand...

FWIW:

Yeh it's only swapping a couple wires. You can check the pots with a meter. If you soldered ground wires to the pot backs in the transfer that could have damaged a pot. You have to get the pots pretty hot to get a decent ground.

In fact I started running shielding strips between pots on the floor of the control bay to eliminate ground wires, having to solder them, and potential damage to the pots. And some pots like blends, there's no decent place to solder to.
 
#6
luknfur said:
FWIW:

Yeh it's only swapping a couple wires. You can check the pots with a meter. If you soldered ground wires to the pot backs in the transfer that could have damaged a pot. You have to get the pots pretty hot to get a decent ground.

In fact I started running shielding strips between pots on the floor of the control bay to eliminate ground wires, having to solder them, and potential damage to the pots. And some pots like blends, there's no decent place to solder to.
Click to expand...

That's what it must be. I replaced the pots, and it stopped making the noise. Now I'm gonna have to shell out $20 for a stacked 50K pot.
 
#7
Hey Jive1,

did you solve your issue with OBP-3? I am having a very similar problem - if the Mid or blend are not centered, a noise mixed with FM station appears. :confused:

I am trying to do grounding again for the 3rd time, but I think that it won´t work.

Regards,
 
#9
I am having the same problem. I dropped my modulus q5 with bartolini and OBP-3 pre at the local repair guy last week. I was having popping/hissing problem when I used the treble knob on my stacked pot. I had the guy replace the stacked pot. Now the problem is even worse. Even when I turn the Trebel DOWN from center I get the same noise.And now when I turn the mid pot up I get the same noise, which before the repair I wasn't getting off of that pot. Bad preamp? Have him replace the mid pot? Frustrating because I brought the bass there with 4 brand new pots and he said the pots didn't need time replaced, and the "little" noise he's getting is from the preamp and he can't fix that. It's a ton of hissing/crackling. Not something I can ignore.

Any thoughts? Bad preamp? Bad wiring job on new pot? Replace the miss pot and see?
 
#13
bigbabasilo said:
I am having the same problem. I dropped my modulus q5 with bartolini and OBP-3 pre at the local repair guy last week. I was having popping/hissing problem when I used the treble knob on my stacked pot. I had the guy replace the stacked pot. Now the problem is even worse. Even when I turn the Trebel DOWN from center I get the same noise.And now when I turn the mid pot up I get the same noise, which before the repair I wasn't getting off of that pot. Bad preamp? Have him replace the mid pot? Frustrating because I brought the bass there with 4 brand new pots and he said the pots didn't need time replaced, and the "little" noise he's getting is from the preamp and he can't fix that. It's a ton of hissing/crackling. Not something I can ignore.

Any thoughts? Bad preamp? Bad wiring job on new pot? Replace the miss pot and see?
Click to expand...

I had the same problem so I read somewhere wrapping the preamp with foil and a plastic bag. First I doubt for a minute but later hands on and voilà…the noises are almost gone. Not tv interference, no more FM noise, no more hiss…my obp3 is now very quiet.
 

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