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What head for custom 2x12?

Discussion in 'Amps and Cabs [BG]' started by Carter Andrews, Jul 17, 2018.


  1. Carter Andrews

    Carter Andrews

    Feb 23, 2018
    Hey TalkBass, I have posted a few times here looking for help and I am still learning a lot about audio equipment. I have built a custom 2x12 bass cabinet using these speakers http://www.usspeaker.com/beyma 12wr400-1.htm and this for the cab itself Bill Fitzmaurice Simplexx 212 DIY Flat Pack Keyboard-Bass Guitar Speaker Kit and I have been researching what head I need to properly power it. I was looking at this GK MB-Fusion 800 Gallien-Krueger MB Fusion 800 800-Watt Ultra Light Hybrid Micro Bass Head and before I jumped the gun on it I wanted to get some of your opinions on whether this is a good choice or not and if there are better heads for my setup. I plan on playing mostly classic rock and plan on gigging with it in the future.
    Thanks!!!
     
  2. JimChjones

    JimChjones

    Aug 6, 2017
    SE England
    Well, there isn't much junk around any more (not from the major players anyway), not like the 70s when some amps were dreadful. So it just comes down to which sounds good. By the time one allows for your instrument, your FX (if any), your playing style, your cabinet and your taste, can it really be possible to make a well founded suggestion?
     
  3. My first question would be, did you get the 4 ohm Beyma or the 8 ohm version? Did you wire them in series or parallel? Depending on those answers you could have a cab with anything between 2ohm and 16ohm impedance, so that would make a difference to the amp you choose.

    I’ll assume for one moment that you’ve got two 8 ohm drivers, wired in parallel to get a 4 ohm impedance cab. From your choice of two 400 watt drivers, to make a nominal 800 watt cab, you seem to be matching it with an 800 watt amp. Makes logical sense, on the face of it, but bear in mind that 800 watts is the thermal rating of the drivers (how much power it will take before the voice coils melt), but this is a very poor indicator of how much power the cab will handle. The maximum power that nearly all cabs can handle will be excursion limited (how much power they can take before the voice coils exceed their limit of travel, or xdamage), and this can often be only around half of the thermal rating.

    I’m a big fan of Bill’s designs, I’ve built 7 of his cabs myself (2 Jack Lites 12, 2 Wedgehorn 8s, Simplex 18, 2 SLA minis - all for PA though), they work well but are still subject to the laws of physics. I’ve only played a GK MB800 once, but remember it as very powerful and loud. I can’t imagine anyone needing more power for most gig situations and it should have more than enough oomph to power your cab. It doesn’t matter that it has more power than your cab will handle, just go easy on the bass boost and, if you hear the cab distorting, turn it down.
     
  4. Carter Andrews

    Carter Andrews

    Feb 23, 2018
    OK that helps a lot. Do you think I should stick with 800watts for my head and just keep it turned down or maybe buy a lower wattage head? I have the 8ohm speakers and wired them parallel to get the 4ohm of impedance and I also read that the xdamage of these beyma speakers is 30mm
     
  5. mmbongo

    mmbongo Five Time World Champion Supporting Member

    Aug 5, 2009
    Carolinas
    Mesa Subway D800 for the win!
     
  6. MyMusic

    MyMusic

    Jun 1, 2010
    Dover, De
    +1000 for the Mesa Subway D800/+.
     
  7. There’s no problem in having a head that can overpower your cab, just as long as you realise that it can do so and use it with a little common sense. Basically, if you hear the cab start to distort and fart it’s time to back off the volume...if your tone uses a ton of bass boost, this may happen at lower volume. Of course, this will be more difficult to tell if your cab is distorting you use a dirt pedal or overdrive as part of your sound but, to be honest, I think your intended rig will have more than enough for most gigs.
     
    Carter Andrews likes this.
  8. Carter Andrews

    Carter Andrews

    Feb 23, 2018
    Thanks! This was really helpful
     
  9. Please give Bergantino amps a listen
     

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