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GK 400RB/115 combo issues

Discussion in 'Amps and Cabs [BG]' started by DiabSoule, Feb 24, 2013.

  1. DiabSoule


    Feb 24, 2013
    I'm sure this has been covered before but I don't have time to scour forums for this specific topic. So sorry if I'm rehashing old crap, and all apologies (get over it) to those who may be butt-hurt over seeing the same stuff repeated on forums lol

    I have a GK 400RB/115 combo, bought used, it sounded fantastic in the store and at mid volumes at home, but when I cranked it at practice, the speakers were farting like they ate 12 buckets of beans the day before. Bad distortion (clean channel), no increase in volume after about 3/4 turned up on both volume controls, absolutely no low end (had to turn bass boost and EQ bass levels to zero to alleviate the distortion) and keep all tone knobs on my bass mid-level to keep tone flat. My sound sucked. I realize I'm limited on things with a combo of this size but I wasn't expecting it to sound this bad. Anyone have an idea of what could be causing this issue and how to fix it?
  2. JonnyAngle

    JonnyAngle Dropping Acid Pedal Etching .com Supporting Member Commercial User

    Nov 24, 2008
    Maple Grove, MN
    You are expecting too much from your amp. You need to turn the bass knob down like you did. The 400RB is not the amp of choice if you want clean and clear, its nature is growly. Try turning the mids up and the bass and treble down
  3. RickenBoogie


    Jul 22, 2007
    Dallas, TX
    Loud bass needs big and plentiful spkrs. The 400 RB is a fine amp, but expecting a single 15 to carry you in a band is unrealistic to say the least. Will the combo take an ext spkr? If so, find a GK 8 ohm 1x15 cab and hook it up. BTW, your op doesn't need to be quite so snarky. You'll find folks here eager to help, but being polite is expected.
  4. DiabSoule


    Feb 24, 2013
    Well I may be a bit snarky but that's only because I've been on too many forums with people who take themselves way too seriously. So I do apologize for that but in general, polite people are a rarity online and I tend to have defenses up... In any case, thanks for the info. I knew what to expect from an amp of this size, it's not my first run with one like it. The guitars weren't terribly loud, you can talk to each other pretty easily without screaming while jamming. The drummer wasn't even playing that hard. I just was shocked to lose all my low end. That kind of defeats the purpose of playing bass. It has an output for an external cab, but it says "one or two 8 ohm cab or one 4 ohm cab," so does that mean if I hook up another cab that I'd have to replace the 4 ohm in it with an 8 ohm, or just bypass the stock speaker and get a cab with two 8 ohm 15's? If so, that seems like a waste of the combo, as I'd only be using the head. What if I removed the head and used it on a different cab altogether?
  5. funkingroovin

    funkingroovin Conquering A-D-D,and all the other notes as well!

    Apr 19, 2009
    It means that you can run down to a 4ohm load through the ext jack,be it a single 8ohm cab(fine) or two 8ohm cabs(for a 4ohm total load) or a 4ohm cab,thus allowing the head to produce it's full output.

    As mentioned above,the 400rb is famous for that GK growl..for a clean tone on mine I have to set the boost and bass at about 9o'clock,the low-mid about 10-11,and the high-mid and treble at 12..BUT-mine's just the head,not the combo. That being said,it's all I need to push a single 15 cab for small/medium gigs w/a full band..
  6. Also try the master at 3:00 and from there turn up the volume (it is actually the preamp volume) to needs. The boost and master volume are interdependent so if boost is turned up high you need to back down the master some.
    You can hook up one 8 ohm extension cab with the internal speaker, so a 115 or even 215 will go a long way.

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