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Markbass Combo II Amp cutting out when slapping

Discussion in 'Amps and Cabs [BG]' started by Fabiojuanton, Jul 26, 2012.

  1. Fabiojuanton


    Jan 30, 2012
    Hi guys, I have a Markbass Combo II Amp (it's a 2x10 speaker, with the amp head built in so it's a combo) and a 4x10 Gallien Krueger speaker that I put under it.

    My problem is in the middle of gigs, when I have my highs cranked and I'm slapping, I will just cut out. On my Markbass, the blue light is still there, the fan is still going, just no sound. A quick flicker of the switch off and back on will make it come back fine. However, it's extremely annoying as you could imagine and it needs to get fixed.

    This wasn't a problem for about a year, then right before a gig, I switched out a battery on my active bass (I play an Ernie Ball Musicman Stingray 4 string). I thought it was a new battery, but apparently it was old. I cut out several times during the gig and it was BAD. I looked online, and other people had similar experiences when slapping and said that if you replace your battery, it should be fine. I did that, and it was good.

    Then this last Saturday night at another gig, it cut out again. I was frustrated because it had been fine for about a month and a half. It cut out another 2-3 times throughout the night.

    My question for you guys is: how often should I be replacing the batteries in my active bass? It's weird because I had originally gone about a year without replacing my battery, and I never cut out. Now, it cut out after just 1.5 months with a fresh battery. Is the battery really the problem?

    Also, any other Markbass users that have this similar problem? I'm really at my wit's end here, I went to guitar center today and they wanted me to spend $400 to buy an Ampeg head to connect to my Gallien Krueger, so my Markbass Combo only had to run itself. Their theory was that the Markbass was overheating because it had to power itself as well as the Gallien Krueger. So they wanted me to bi-amp with the Ampeg to the Gallien Krueger, and the Markbass would be on its own. The only problem was that it sounded terrible, and I don't think I need to spend all that money to solve this problem.

    Any help is much appreciated, thank you so much.
  2. Russell L

    Russell L

    Mar 5, 2011
    Cayce, SC
    Never a problem with my Combo Head or Little Mark III head. Are you sure the head is the problem?
  3. Fabiojuanton


    Jan 30, 2012
    I am pretty sure, yes. It gets fairly hot too. Again, the blue power light and the fan are still on, but the sound cuts out. I can literally flicker the power switch off and back on again immediately and it will work fine.
  4. You could always refrain from slapping.

  5. Fabiojuanton


    Jan 30, 2012
    Haha, you're funny ;)

    I mean, mostly it happens when slapping. But I remember the first show this started happening it wasn't just the slapping, it was whenever I played anything with a lot of force.
  6. owendavis


    Jan 12, 2011
    So does a fresh battery in the bass fix it?

    Have you tested it with a different bass?

    Does the Markbass combo cut out without the GK hooked up?
  7. Yeah you really need to isolate the problem by trying a different battery, a different bass, a different pre into the effects return and then a different power amp/speaker - coming out of your Markbass.... and it might help to do it in that order as that's starting with your most likely problem.
  8. JEBassman

    JEBassman Supporting Member

    Jun 25, 2008
    Are both your cabs connected with speaker cables? Have you tried using different speaker cables, and different instrument cables for your bass?
  9. Fabiojuanton


    Jan 30, 2012
    Those are some good points.

    Owendavis: Yes, a fresh battery seemed to fix it the first time, but a month and a half later the problem persists. So I was curious if anyone knew how often I should be changing the battery for this specific problem. I have not tested it with a different bass, and no, the Markbass combo does not cut out without the GK hooked up.

    JEBassman: My Markbass and GK are connected with a speakon cable. I have not tried using different speaker cables or instrument cables. I'm not exactly certain that that is the problem however.

    I also did some research online. If you go to this link: http://www.musiciansfriend.com/amplifiers-effects/markbass-little-mark-iii-bass-amp-head

    then click reviews, the 5th comment down is an anonymous poster describing the exact problem I have. He says "I think the percussive spike (overload at the input signal?) from the slap bass, is triggering a protection shut down circuit" which sounds like exactly what is going on with mine.

    Perhaps that helps?
  10. Do you unplug your bass when it's not in use? Not doing so can drastically reduce battery life.
  11. David1234


    Jun 1, 2004
    Sydney, Australia
    Endorsing Artist: SWR Amplifiers
    I'm wondering if you're overheating the amp. Are you definitely using the right impedance extension cab? Has it ever happened without the extension cab?
  12. JimmyM


    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Most of the time, batteries will last months.
  13. When you slap you are putting in much bigger gain spikes and it is causing the protection curcuit to activate... try cutting back on the gain and using more master volume or vice versa, and you should be able to find a balance of the same volume that doesn't clip

    I have seen this a few times before, not sure if it is the protection circuit that is faulty and coming on too early or what?
  14. StraightSix


    Nov 23, 2011
    I would always suggest a compressor for slapping as it controls the peaks to prevent overloading the amp.
  15. punchclock


    Mar 19, 2007
    Kansas City
    it's not your battery.
    I had that exact problem with my orange terror bass 500. and if you search the ampeg pf350 &/or pf500 - you'll see a lot of people have that issue with those as well.
    it is a sensitive protection circuit in class D amps.
    I was talking with my amp tech yesterday & he said the same thing. class d is light, that's great. but to keep from blowing up your speaker cab with signal spikes - they cut out.
    orange told me it was bad power from the venue, bad speaker cable, etc. but they kept sending me new amps (good customer service).
    orange has adjusted the level of their protection limits. and after receiving my 5th different unit - I haven't had a problem. but I also don't play it unless I have to - I got an Aguilar db750.
    no class d = no cut out.
    but in all the research I've done I have not found any class d from Aguilar (th350, th500), genz Benz or GK that cut out.
    I don't know if they all have better settings for their protection circuits or it's the power amp unit (aggie, gb & gk all use bang & olfsen class d power amp units in their micro heads)....
    bottom line: you aren't crazy. your problem is not unique. it is a common issue with a lot of manufacturers with class d amps.
  16. kasbrey


    Aug 23, 2002
    Northampton UK
    1 - The Markbass LM3/Combo11 head isn't Class D

    2 - The problem will more than likely be with the GK cab's impedance being actually below the 8 ohms stated. The total impedance will be less than the minimum 4 ohms. Do a search for the problem - I seem to recall it happened a lot with EA cabs. Other heads too.
  17. We were testing a LM III head doing the same thing at the shop the other day, other exact same heads don't cut out at the same level so I'm guessing something is faulty with the protection circuit or somewhere else in the amp causing it to cut out earlier...
  18. Fabiojuanton


    Jan 30, 2012
    So, my Gallien Krueger speaker is 400W and 8 ohms.

    My Markbass combo is 600W and I can't find how many ohms it is. With a quick search on the Markbass website, this is my amp: http://www.markbass.it/product_detail.php?id=39

    However, it says it's 300W (500W with 8 ohm extension cabinet).

    Dunno why it's different than what I have, it's the exact same one.

    Could the difference of ohms be the problem?
  19. kasbrey


    Aug 23, 2002
    Northampton UK
    The problem could be whether the GK cab is truly 8 ohms and not, say, 7.6 ohms.
    Coupled to the 8 ohm Markbass combo (for that is what it is) the combined impedance could be enough below the 4 ohms minimum required to cause a problem (when slapping etc.).
    Some heads (like the Markbass) are better protected against this than others.
  20. StraightSix


    Nov 23, 2011
    Fabio - your Markbass combo is 300W RMS and will be 500W RMS with your GK cab added.

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