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Problems with my SVP PRO (HELP!!!!!)

Discussion in 'Amps and Cabs [BG]' started by Deano Destructo, Feb 22, 2002.


  1. Deano Destructo

    Deano Destructo Music Man/Upton addict. Hasn't slept since 1979. Supporting Member

    Dec 10, 2000
    Austin, TX
    I having a huge problem with my SVP thats actually making me want to get rid of it:eek: . I bought it used and since I recieved it anytime I turn the gain nob on it up beyond a 1/4 of the way it clips like crazy and it always sounds super muddy:mad: . Please tell me this isn't normal. All this is with the -15db button pressed in ,other wise it does nothing but clip. I've replaced the tubes in it since I got it and it hasn't helped much if at all. Also what purpose does the 12au7 tube in the older models serve? HHHEEEELLLLPPP!!!!!:( :confused: .
     
  2. ThunderStik

    ThunderStik Guest

    Jun 25, 2001
    Claremore OK.
    Where do you have the master set? Gain is is actually that, if you have your master set low and you raise the gain you will get the "driven" sound. If you dont like it turn the drive all the way down and turn the gain down, then turn the master up most of the way. Then adjust the gain up slowly. What is the rest of your signal chain?
     
  3. Deano Destructo

    Deano Destructo Music Man/Upton addict. Hasn't slept since 1979. Supporting Member

    Dec 10, 2000
    Austin, TX
    Masters only set at about half way up, which i would'nt think would cause it to clip. I'm running it through a mackie 1400i (mono , 8ohms each channel) into 2- 4x10 mesa boogie RR cabs.
     
  4. cb56

    cb56

    Jul 2, 2000
    Central Illinois
    Not a tube expert here at all but from what I understand the 12au7 is a similar to the 12ax7 with less output I believe. And should be the last tube in the pre amp before going to the power amp on all even new models. So if it has been replaced by a 12ax7 that may be where the trouble is. Correct me if I'm wrong tube guys but I think this would be worth looking into. I had an new SVT3 pro briefly and I know the 12au7 was the last tube in the drive stage.
     
  5. Deano Destructo

    Deano Destructo Music Man/Upton addict. Hasn't slept since 1979. Supporting Member

    Dec 10, 2000
    Austin, TX
    The way the tubes are in order in mine (I'm not positive if this is how there supposed to be) is when the preamp is faceing you and you look down at it they go from right to left as 12ax7. 12au7, 12ax7, 12ax7, 12ax7. I hope that this is correct.
     
  6. ThunderStik

    ThunderStik Guest

    Jun 25, 2001
    Claremore OK.
    Try what I said before. Is it cutting out or are you getting the distortion "effect" of the preamp? You can get distortion by turning down the master and turning up the drive and the gain is it this type of distortion? Also how long have you had this setup? Have you gigged with it? I know you dont think that matters but the reason I ask is your power amp is not putting out much power at 8 ohms, if it is power amp distortion then you need to bridge the amp and daisy chain your cabs together and you will recieve the full power of your amp into the 4 ohm load. I believe at 8 ohms stereo your amp is only putting out 250-290 watts at full power(per side) and you may be encountering amp distortion. We need to find out if it is amp clipping or preamp clipping or the distortion "effect" of the preamp.
     
  7. Deano Destructo

    Deano Destructo Music Man/Upton addict. Hasn't slept since 1979. Supporting Member

    Dec 10, 2000
    Austin, TX
    When I "daisy chain" I get the same problem. I'm running little drive through the preamp and even with the drive all the way down and the gain set as above it still clips. The poweramp to my knowledge judgeing the LEDs is never clipping. I assume the way I normally run it is mono, since it goes from preamp out to poweramp channel one in from poweramp channel one to first cab and poweramps second channel to second cab ( thats mono right?).
    I've tried running out of the poweramp channel one into one cab and running the second cab parallel out of the first cab (daisy chain right??) and there does'nt seem to be a sign of it putting more power out. When daisy chaining how do you set the amp as far as bridge, mono or stereo ( briged right?):confused: :confused: :confused:
     
  8. ThunderStik

    ThunderStik Guest

    Jun 25, 2001
    Claremore OK.
    Well that narrows it down, you either have a dead battery in your bass or you definately have a jacked up preamp. I have never had any problems with mine and there are quite a few of us that use them. I would take it to reputable service tech and have it checked out because that does not sound right. The only thing else I would check is make sure you have the amp in bridge mode when chaining and you battery in your bass if you have one.



    Damn!!! Dont you just hate trying to put sound into words. Its like trying to describe the color blue to a blind person.
     
  9. Deano Destructo

    Deano Destructo Music Man/Upton addict. Hasn't slept since 1979. Supporting Member

    Dec 10, 2000
    Austin, TX
    Also I forgot to add and I'm not sure it helps but this preamp hisses like crazy most of the time its on. I guess I'm still wondering if it could be a tube related problem:confused: ?
     
  10. FalsehoodBass

    FalsehoodBass

    Jul 22, 2001
    Denver, CO
    i had that hissing problem when i first got my SVP brand new. It was still under warranty, and the tech guy had to replace an open resistor, and maybe a preamp tube. Ever since then it's been great.. i play mine into a mackie 1400 also..
    You should take the preamp in to a tech to have it checked out. Buying used amp equipment has never turned out well in my experience...the money saved has always been spent in repairs.