AMPEG SVT 4 Pro Makes Fuzz Sound *help*

Discussion in 'Amps and Cabs [BG]' started by Snerek, Dec 28, 2007.

  1. Snerek


    Jan 12, 2007
    Brought my SVT 4 pro to the practice space yesterday and i noticed that when i was playing it, it sounded like a fuzz, dust sound coming out really faint. it was still working but this sound was weird. i do have an active bass, so i thought it could have been the bass, but i tried a different one and new cables and the problem was still there..

    anyone know about this problem?
  2. a-lenthe


    Jul 27, 2007
    how old are the tubes?
  3. Jazzman


    Nov 26, 2002
    Raleigh, NC
    Sounds like a bad solder joint to me. What year was the head made?
  4. Snerek


    Jan 12, 2007
    the tubes are about a year old but i have not used it much..

    whats a solder joint? it was made in '05/'06 i think
  5. asad137


    Jan 18, 2007
    Is the "fuzz" more noticeable at low volume levels? The SVT-III Pro has a little adjustment for the output transistors that, if its out of whack, produces a fuzziness that's especially noticeable at low volumes.

    I'm not sure if the SVT-IV output section is similar; maybe Jerrold can shed some insight.

  6. Jazzman


    Nov 26, 2002
    Raleigh, NC
    A solder joint is a joint where two components/items are soldered together.

    I asked for the year because I was curious as to whether your unit had lead-free solder.
  7. Does it do it at home, too?
    Or any other place?
    Have you played it there before, and was it OK then?
    Could it be the wiring in the house or other interference?
    Does it do it while playing only or whenever it is on?
  8. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    Bias is a LOT less fussy on the 4PRO. Unlikely to be a problem.

    Anyway, this is a lack of sound, not just fuzz, right? Tinny, low volume?

    Plug a cord into the line-in/line-out jacks a few times and see if it gets better. if so, some contact cleaner is needed.

    if not, probably a cracked solder joint, most likely on a jack, but possibly elsewhere.

    You can also check to see if a signal from a pre will still drive power amps thru the line-in jacks. If so, problem is in preamp.

    That's a complex unit with a ton of jacks etc. lots of places for problems.

    On the off-chance that you meant that the fuzz sound was faint but the sound was OK otherwise, check for speaker problems, air leaks etc.... If that is what you meant, does the peak light light all the time? As a last possibility, possible that the bias is bad.