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Treble hiss on a Warwick Corvette Active, Shielding Issue?

Discussion in 'Basses [BG]' started by michaelc, Mar 25, 2009.


  1. michaelc

    michaelc

    Apr 17, 2007
    C-ville Michigan
    I have a warwick corvette std with a retro-fitted MEC preamp (so even though its the passive version its exactly the same as the active version.) Anyway it's really quite noisey when I stand to close to my amp or other electronic devices. I have some copper shielding tape kicking around, but does that trick even work with active basses? Shouldn't the shielding paint in the bass already be enough?
     
  2. is it noisy with the treble down?

    if not then welcome to the world of active basses, just compensate with the amp eq
     
  3. A LOT of preamps get hissy when the treble is turned up high.

    It could also be picking up 60 cycle hum from your pickups and amplifying it through the pre.
     
  4. pondscum29

    pondscum29

    Feb 23, 2006
    Sacramento, CA
    I'm hoping to bump this, as I have a Warwick $$ that I realized puts out a lot of hiss in active mode (I haven't run in active in a looooong time, and never noticed it before). In passive, no problem. I would think a grounding issue would be hum, not hiss, and also show up in passive mode. The hiss even sounds a bit, shall a say, gurgly? Yep, fresh battery too. My active Pedullas, no hiss. Any insight? Thanks!
     
  5. dcocharro

    dcocharro

    Mar 7, 2008
    Portugal
    Does anyone knows how shielding in warwicks works?
    I heard that they use some kind of material, which is the reason why the electronics box in their basses looks kind of dirty.

    thanks,
    dc
     
  6. curlyback

    curlyback

    Nov 5, 2007
    My Warwick SS 1 also hisses even when all EQ and volume all the way down.
    In passive mode, no hiss.
    MEC pre is noisy.
     
  7. dcocharro

    dcocharro

    Mar 7, 2008
    Portugal
    In my research I found that the shielding in instruments are based in the principle of the Faraday Cage.
     
  8. dcocharro

    dcocharro

    Mar 7, 2008
    Portugal
  9. xring

    xring

    Sep 16, 2003
    Ohio
    From what I've read, active factory Corvettes have active Gold MEC pickups. I presume the passive has passive pickups. Maybe that comes into play?
     
  10. LenMinNJ

    LenMinNJ Supporting Member

    Dec 22, 2010
    I had a hiss problem in active EQ mode on my 2000 Warwick Thumb NT.

    I researched it on the Web and found that it was not uncommon for the years around 2000.

    The solution is to change the TL-062 (8-pin) integrated circuit to either a TL-072 (lower noise, but slightly higher power consumption) or, even better, an AD-822 (even lower noise, but a bit higher consumption than the TL-072).

    And change the TL-064 (14-pin) to a TL-074.

    The trade-off is slightly shorter battery life. But the reduction in hiss is worth the trade-off.
     
    Last edited: Jul 4, 2017
  11. somebrains

    somebrains Supporting Member

    Feb 7, 2017

    PM'd you.
    I have a 3-band that hissy I wanna try chip swaps to reduce the noise.
    Found a couple options for each and unsure what to buy.
     
  12. LenMinNJ

    LenMinNJ Supporting Member

    Dec 22, 2010
    I responded to your PM. Use the PDIP form factor.
     
  13. somebrains

    somebrains Supporting Member

    Feb 7, 2017
    PSA - Take pics before you desolder an opamp, I did the whole "which way was the divot orientated?" after I'd soldered it in.

    TL074CN was $2.75 at my local electronics store.
    AD822 is hard to find, had to order it from Mouser.

    I historially have disliked the 2-band MEC preamps, but loved the 3-band.
    I think it goes back to when I could walk into a GC and play a bunch of Thumbs in the 80's and 90's.
    They have a different sound, and the 3-band sounds really good with a set of GZRs.....except for that hiss.

    Haven't reinstalled it yet, will report back when I get thru all the Xmas chores.

    I used a Hakko set to 800, solder wick was fine except I had 2 hard joints that needed a solder sucker bc I was on it for so long.

    3-band before. 3-band after.
     
  14. somebrains

    somebrains Supporting Member

    Feb 7, 2017
    AD822 came a day early from Mouser.
    Man, it makes a world of difference.
    This thing is useable now.
    Next step is figuring out how I can go 18v, not much room left in my Vette.
    for a 2nd 9v but that's on me.

    Thanks a bunch!!
     
  15. LenMinNJ

    LenMinNJ Supporting Member

    Dec 22, 2010
    I would have recommended that you install two sockets and not solder the new ICs directly into the board.

    You're welcome!
     
  16. somebrains

    somebrains Supporting Member

    Feb 7, 2017
    Yeah that would have been smart, but I come from people known for very fine hand eye coordination and not much impulse control.
     

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