Understanding how a compressor works

Discussion in 'Amps and Cabs [BG]' started by Beefbass, Apr 1, 2001.

  1. Beefbass

    Beefbass Guest

    Feb 4, 2001
    Hey everybody, recently I had posted about a problem I was having with my Peavey Combo 115. The sound would momentarily fluctuate on it's own. Bumped up the gain to 5, and lowered the master volume. While I get a good tone , the problem occured Friday night. This time however, I discovered that this only happened when the compressor/limiter was turned on. Turn it off, no problem whatsoever.( This is not the DDT by the way.)
    My question; this compressor has it's own level, and adjustment for the ratio. I have never owned an amp with that kind of set up before. Could it be the way I set it? What exactly does the ratio mean anyway? I know it's probably a dumb question, but other amps I've owned either had no compressor, or a push one button and it's on set up.
    Again, my friend thinks it's probably due to way way I set it, and not a defect. Any help you can give would be greatly appreciated.
    Incidentally, I think it sounds just fine with it shut off anyway.
    Peace, and thanks again everybody.
  2. brewer9


    Jul 5, 2000
    Good question. I'll bump it to the top.
  3. leftybassdog

    leftybassdog Senior Supporting Member

    some compression units will change your sound and drop your bottom end. i use one for slap and funk but not the unit built in my amp. i use a bass compactor by tech 21. it has a high and low control that cut and boost when needed. a limiter or compression unit threshold and ratio controls are where the compressor turns on and the amount of compression. if you play and start slapping the threshold can be set to kick in when the output is increased. the ratio is how much compression you want. 1to1 or 15to1 or more in some units. most bass amps are preset to limit from the factory. and you will hear it kick in { limiting is like full ratio or heavy compression} your best bet is if you dont like the compressor in your amp bypass it. or use a outboard unit. good luck and i hope this was some help.
  4. rickbass

    rickbass Supporting Member

    One thing that good article Treb put up doesn't menion is "soft knee" compression. It's one of the features I like about my Carvin amps.

    When compression takes your signal from low to high or vice-versa, the change can be dramatic, (sounds like yours), instead of a gradual shift, which is what soft knee compression does. It used to be that studios were the only place you encountered soft knee compression but that has changed a little. Yet, most amps I know of still don't use the technology yet.
  5. On the tube v. solid-state posts a few days ago, this is what I was talking about. Tubes have a kind of natural soft-knee compression built in. The most coveted studio compressors are tube models as well, although they also use external components like Light-detecting resistors and such to make the soft-compression more pronounced and adjustable.