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Kustom Groovebass 1200 Review

Discussion in 'Amps and Cabs [BG]' started by Marley's Ghost, Mar 31, 2006.

  1. Marley's Ghost

    Marley's Ghost Gold Supporting Member

    Feb 9, 2002
    Tampa, FL
    I bought my Kustom Groovebass 1200 new on ebay about 2 weeks ago. The silver and chrome front panel and blue power light are pleasing to the eyes. My first reaction was that it did not seem as loud as 1200 watts should be. After experimenting with numerous different gain and EQ settings, I finally hit on a sound that is really warm and punchy. And LOUD. It is so warm that I only need to use my BDDI now to add tubey distortion, although the Kustom does that pretty well too. The real mass of volume is at the high end of the knob, after 12. With my 2 ohm load, this thing DESTROYS guitars! The guitaist in my band plays thru a Marshall full stack, and this cuts through like a hot knife through butter. It is a little heavy, at 31lbs, but not too bad. It was a sweet deal at $520!

    Oh yeah, this baby is QUIET. No fan. You can't even tell it's on without the power lamp.
  2. thestevo


    Aug 12, 2004
    Yeah, these are sweet amps. I use mine with an Avatar 212 and also a Sansamp to get that nice tubey sound as well. I never find the volume to be lacking at all, and I only use mine with a 4 ohm load. I can't imagine what 2 ohms at 1200 watts would be like...:bassist:
  3. jpark


    Feb 2, 2006
    I play mine through an ampeg svt410he and a svt1510he (1x15, 1x10 with a horn). This thing is LOUD!!! Mine stays about 4 on gain and volume.

    The amp itself is quiet, there's a fan on the back of mine marley's ghost but it's very quiet. I get a little fuzz, static sound with mine but it's nothing bad. It's the exact tone I've been looking for, and at a great price to boot.


    Jan 25, 2005
    Des Moines, IA

    It's tasty...I run mine thru a 2x10 and 2x12 for a 2 ohm load....never had the pre-gain past 12:00 and the master past 1:00...this thing has the thunder!
  5. can i run a 2 ohm load into a 4 ohm cabinet?
  6. If you mean is it possible for a 4 ohm cabinet to look like a 2 ohm to the amp? The answer is no not really. Best way to get full power is to get another matching 4 ohm cab.


    Jan 25, 2005
    Des Moines, IA
    Right, the load from the amp is determined by the electrical resistance of the speakers and wiring in the cabinets...and if they are wired in series or in parallel.
  8. i could of swore i used to run 8 ohm head into a 16 ohm cab (in my guitar days)

    if you set the head on 2 ohms...plug one output to 1 four ohm cab and dont plug anything into the other output...where is the harm in that?

    say im running to 2 - 4 ohm cabs with a 2 ohm head. one cable falls out the back of a cab...is something gonna blow?


    Jan 25, 2005
    Des Moines, IA
    With the GrooveBass1200, there's nothing to set...... the circuitry senses if there are Neutrik cables plugged into one or both ports and what the resistance is of the cabs connected to those cables.

    There's usually no issue for a cab to be higher that the head, the problems start when the cab has a lower impedance than the head is putting out.
  10. thats what i was thinking. thanks for clearing that up.
  11. Here's the way I understand it and I'm not an engineer but an old fart who has been playing bass for 30 yrs +. A tube amp (which the Kustom is not) has to have a thing called an OUTPUT TRANSFORMER. This transformer has to convert the power coming from the output tubes into usable power by the speaker. The speaker outputs on the back of the amp are wired into difference places in the transformer (taps) These taps are the places from the transformer that will produce full safe power from the amplifier for different ohm loads. Usually 16-8-4-2. Some amps have a switch and others have a series of jacks and they all do the same thing. So a tube amp will put out its' full power as long as you have the speakers ohms matching the amps selected output ohms.

    SS amps don't need or have an output transformer. The power from the output transistors can go directly to a speaker. This output power can go to any load down to the minimum the amp is rated. In the case of the Kustom it is 2 ohms. Most SS amps are usually rated at either 2 or 4ohms min. Another characteristic of a SS amp is that the lower the ohms of the speakers the more power the amp can produce. But, the more power the amp produces the more heat it also creats. If you try to operate the amp at say 1 ohm it will either trip its' thermal protection or eventually self-distruct. Just about all modern amps have thermal protection circuits.

    How do you determine the speaker load. Well each speaker cabinet has a rating usually 8 or 4. Think of the power from like water through a garden hose. 8 ohms is like 1 sprinkler hooked to the hose 4 ohms is like 2 sprinklers get it. The more sprinklers you have on the same hose the more water can flow with less back pressure. Ohms are sort of like that. an 8 ohm speaker will only let say 200 watts flow through the outputs add another 8 ohm speaker in parallel and you cut the resistance in 1/2 to 4 ohms and the amp will allow 350 watts or so flow through the outputs. add another 8 ohm speaker and you cut it to 2.6 ohms and the amp will let more flow, and add a 4th and final 8 ohm cab and you down to 2 ohms and the amp will produce its' full rated power.
  12. Joe Beets

    Joe Beets Guest

    Nov 21, 2004
    I think I've got it now. If I plug my amp into a 4 ohm cabinet, then I'm running a 4 ohm load. If I were to plug my amp into, let's say, an 8 ohm cabinet, then I'm running an 8 ohm load. The load on the amp must be related to the cabinets that I plug it into. :smug:
  13. And just to clarify, here are the power ratings.

    450w at 8 ohms
    750w at 4 ohms
    1200w at 2 ohms

    And I love the pretty blue light.



    Jan 25, 2005
    Des Moines, IA

    THAT'S REALLY GOOD.... (from an old fart) :D

    Seriously, one of the best non-technical definitions I've ever heard..and I understand the physics of this stuff!!!
  15. i have a 900 watt 4 ohm cab. how do i get the most volume out of the kustom 1200 head?

    and also, as previously asked why can i not put one speakon output to my cab and just have a "dummy" speakon in the other jack, so the head will operate at 2 ohms but only be "safely" sending to my one 4 ohm cab?

    seems like it would work at getting 1200 watts running for my cab..(and i wouldnt fry the speakers unless i dime the head)


    Jan 25, 2005
    Des Moines, IA
    As previously mentioned, the wattage you will get out of a 4 ohms cab will be 750 watts...but that's subjective. Watts is a measure of power, not perceived loudness. I've run my GrooveBass with a 4 ohm 2x12 cab..pre gain @ 12:00 and the master @ 12:00 with an inverted scoop, and run a ton of rigs out of the place.

    Hooking a "dummy" Neutrik cable only allows for the load within the copper wire itself (not too much). Electricty runs in a circuit and to the least impedance. The GB1200 will recognize that only one port has resistance on it....I doubt it, or any other quality head, can be "fooled" that way.

  17. You need to get another 4 ohm cab to use the head's full power. Even if you could fool the amp, you don't want to run it's full 1200 watts into a cab that can only handle 900 watts.


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