Warwick active on board preamp problem

Discussion in 'Pickups & Electronics [BG]' started by orangejulius3, Nov 28, 2013.

  1. So, my Warwick Corvette $$ 4 string started making a swishing noise whenever the treble pot was up (like if I was at the beach) I believe even the bass pot is the same way but is barely noticeable.

    It would go away if the treble pot was lowered all the way or if I switch over to passive from pulling up the volume knob.

    It really irritated me today so I stripped all the electronics from the bass as I couldn't see anything wrong. I will be installing everything tomorrow after I test it.

    Anyone knows what to look for? My only assumption is the preamp went bad. I've already used deoxit on the pots and got no change. Installed a new battery and still no change. I'm probably going to de-solder and re-solder everything this weekend.

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  2. Front side

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  3. Electronics

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  4. Means2nEnd

    Means2nEnd Supporting Member

    Everything looks clean..question does the switching affect that woooshing sound?
  5. As far as switching to parallel, series, or single coil it has the same noise. As far as paning between the pickups, same amount if noise.
    The only way to get rid of it is dialing out treble, dialing out volume, or switching to passive.

    Passive sounds very clean but it also takes away my active preamp.
    On passive, switching between pickups in any order is still quiet besides small amount of hum, but that should be a given.

    I'm almost positive it will be the preamp, what do you think?

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  6. I still need advice!
    I've already looked over my electronic wiring and preamp.
    I found one wire exposed, so I took it out and replaced it.
    I cleaned all pots with DeOxit.
    I left the pick ups out.
    I made sure the jack was working properly.

    I'm still getting the same swooshing (ocean) noise.
    The treble knob brightens it or lowers it, the bass knob can be heard, but the ocean sound sounds muffled.

    Same thing as before. If I lower the treble and bass, the sound goes away, same as switching to passive, problem goes away completely.

    I've decided it has to be the on-board preamp.
    I have done some search and thinking about the Aguilar OBP-2tk with my Warwick MEC double humbuckers. What do you guys think?
  7. grendle


    Mar 4, 2011
    Central FL
    I'd be looking at the battery, volume pot, and possibly the jack. Pre's generally don't go bad but since their the most complex they get the finger. When you deoxit are you actually getting it into the pot? Sounds like a dirty wiper on one of the pots. Mechanical stuff is about 99% more likely to go bad than the electronics. The install looks pretty good from what I can. See.
  8. Hey Grendle,

    I did try 3 different batteries. Same result.
    I do have a cheap spiral jack but it looks pretty secure. Maybe I can use my other basses jack to check if that's the problem.

    I did use DeOxit and the results were the same. Usually the pots have a crackling or noise that fluctuates. This noise is pretty accurate with the volume or treble pot as far as being dialed in.

    I never messed with a pot that is active and passive. Any ideas how to separate the compartments on the volume knob?

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  9. I assume this problem is happening in multiple venues and not just in one ace you play? I thought maybe it could be interference of some sort the preamp is accentuating, like radio or cellphone or something?
  10. Yes. I leave my bass at home and take my other 2 basses.
    I've tried other outlets around the house, plus jam/ practice session at a friends garage. Same noise occurs every time I activate the on-board preamp.

    Tomorrow I'm going to try switching out my jack and volume pot of my other bass. Hopefully I can narrow down what it is.
  11. Crater


    Oct 12, 2011
    Dallas, TX area
    The hissing sound is most likely from a bad transistor or op-amp on the on-board preamp. I wouldn't bother changing the jack or volume pot, those are passive components and won't (and can't) add noise, especially since the bass works fine in passive mode.

    The problem is your preamp, and the solution is to replace it. :( Sorry. By all means, get a second qualified opinion before dropping the $$$ for a new preamp, but I'm pretty sure that's where the problem is.
  12. Crater

    You probably are correct. I didn't have to do any de-soldering though, since I have another warwick with harness, I was able to try the jack and volume knob from my 6 string warwick with just switching out some harness. Same result (ocean sound).

    I've pretty much isolated it to the preamp.

    I'm going to upgrade to Aguilar OBP-2tk on-board preamp with my $$ double humbuckers MEC.
    If anyone does not like this combination or have certain issues, please feel free to share your opinions.
    I am not in a hurry to upgrade. I'll be doing some research before dropping cash on the Aguilar.

    If anyone is wondering why I'm going Aguilar, I have three reasons:
    1. I have heard good stuff about there amps.
    2. They seem solid and trustworthy.
    3. Love the housing of the on-board preamp instead of an open board.
  13. grendle


    Mar 4, 2011
    Central FL
    Only draw back I have heard is if your running the pre full boost there is no trim pot for the output and the aggi can be to hot for some preamps. There's a lot of boost there esp at 18v. Other than that I think that would be a good match.

    Sucks about you pre going out. Their usually solid.
  14. It does suck for the pre to go out.
    I did buy the bass used last year around this time at Sam Ash.
    Don't know if the last owner did anything to provoke it.

    If anything, it was probably my fault. I finally had time to do maintenance on this bass by cleaning the fret board, polishing the body, and I open the rear cavity to use DeOxit on the pots. I had to move some wires around.

    I did this to my other basses with no issues. Kinda through me for a spin. Oh, well. I've kind of wanted to upgrade an on-board preamp on one of my basses. I thought it was going to be my MIM Fender Jazz 4.