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Mark Bass heads problem

Discussion in 'Amps and Cabs [BG]' started by ValmiX, Feb 27, 2008.

  1. ValmiX


    Jan 27, 2003
    Hi everybody, I own a LMK markbass head and a ACME LOWB2 cab.

    The overall sound is fine but i'm having some problems with the sound quality during long time gigs using some gear.

    I play from jazz (from quiet to louder one) to rock blues (SRV, robben ford, elvis kind of things).
    And i usually play with an upright, a p bass with flatwounds (.052) and a bit of compression (analogman pedal) and a TRB 6P yamaha.

    During some quiet long gigs (2.30 hours sometime less) i've noticed that the sound begin to get worse after a while, in particular when i hit the strings a bit harder, seems that the head can't take it anymore and the sound is more confused compared to the beginning of the gig. It never clips by the way. the gain is max at 13.00 (normally at 12.00 or less) and the volume is at 12 or a bit more, not over.

    A couple of times using the P bass with the compressor (rising up a bit the signal) in the lower register the amp began to produce a very low loud tone even if i played really soft, like a sort of larsen but with low frequencies.

    This kind of issues happens in particular with the p bass witch has a very fat sound and a big signal and with the upright where i need to raise up the gain a bit more.

    I talked with some other guys that used to play with MB heads and they noticed the same problem, after a while they need to raise up the gain and the sound starts to get worse. They changed the head using the same cab and the problem disapeared. Probably it's the switching power supply system.

    Has anyone noticed this kind of problems?

    Sorry for eventual english mistakes.

  2. I have no experience with MB heads but lots with the Acme B2. The Acme cab is fairly inefficient, that's the price you pay for low extension in a small box. I feel your problem lies in too few speakers and too few watts. Although I own four B2s, I usually use only a pair. I have played a few gigs with just one but they were very small places. I drive them mostly with a Carvin DCM1000 stereo power amp, one 4Ω B2 per channel. In this configuration the amp delivers 350W into each cabinet for a total of 700W. I have never experienced difficulties with tone, volume or distortion. I think your amp is running out of power as you get louder during the evening until it maxes out. Keeping up with a guitar player doing his SRV impersonation is not a job for a single B2 either IMO. You do not mention the impedance of your cabinet. If it is 8Ω then your amps situation would be even worse. I recommend you get a second B2.

  3. chroma601


    Feb 16, 2007
    Sylva, NC
    I played my LMII for three hours straight last night with no problems. Lots of MB users on this forum, and I haven't seen any reports of situations like yours before. Perhaps you should contact them through their website.
  4. Nick Kay

    Nick Kay

    Jul 26, 2007
    Toronto, Ontario
    It might just be ear fatigue. It might not be the amp that's 'getting tired' as the gig goes on, but your ears instead.
  5. gregbackstrom

    gregbackstrom Supporting Member

    Feb 3, 2005
    Tacoma, Washington
    I have an LMII and a couple of Low B2's. My experience is that the Acmes can take---and like---a lot more power than the LMII can give.

    I know a lot of players use Stewart World 1.2 or 2.1 amps with their Acmes, but my 2.1 used to "fart" from time to time (and the Stewart has much more power than the LMII). I've never had that problem with lead-sled Crest and Mackie amps, however.

    You'll probably solve your problem by swapping out the LMII and getting something more powerful! Good luck.
  6. I regularly use MY LMII for "long" gigs of 3-4 hrs some even 5 hrs & have had NO probs running into Aggie GS cabs or Bergantino NV cabs. Never into an AcmeB@ tho sorry.
  7. gregbackstrom

    gregbackstrom Supporting Member

    Feb 3, 2005
    Tacoma, Washington
    I should have added that I have used the LMII with lots of combinations of Epifani cabinets, and have even driven an Ampeg SVT 810 bottom without any difficulty. But IMO and IME, the LMII won't drive Acme Low B2's to their full output and sonic potential.

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