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Bass amps with impedance selectors?

Discussion in 'Amps and Cabs [BG]' started by Guinness20, Apr 7, 2015.

  1. Guinness20


    Jan 24, 2013
    Liverpool, UK
    I recently put a review up here on the orange terror bass, and while it was decent I was hardly blown away. However, one attribute which may well mean I end up buying one (me and a friend putting money togeether to get a amp and cab) was the switch between 4 and 8 ohms. He's set his heart on a 1x15 bass cab, I'm not delighted but I've got a few things I can sell on and an always buy a second cab.

    I know there are a few 4 ohm 1x15 cabs out there, like the mesa and a schroeder I think, I live in the UK and don't have a top, top budget. So, that led to me thiknig if there were any other amp heads with impedance switchs. Anybody know of any?
  2. You know it's really not needed. All solid state heads will do 4 or 8 ohms without switching.
  3. The power increase to 4 ohms from 8 ohms with a single cab really means very little to actual SOUND output. The numbers make make you feel good, but numbers on paper are not music production. Waste of effort when looking for actual volume.
    Aqualung60 likes this.
  4. edencab


    Aug 14, 2013
    Toronto, On
    Orange Terror Bass 500&1000 have a 4/8 ohm switch, .........so 1@ 8 ohm cab 500 watts, 2@ 8ohm cabs 500 watts, 1@ 4 ohm cab 500 watts.....and they're damn loud watts :thumbsup:
  5. mbelue


    Dec 11, 2010
    My understanding of the Terrorbass is it's Ohm selector switch is used in its poweramp circuitry, current limiter or something.

    Which is weird for a solid state amp.

    Curious what would happen with an 8 ohm load with the switch on 4 ohms. Not recommended by the manufacturer but it does stimulate thought.
  6. Watts are watts it is unit of electrical work performed and not subject to emotional slant ;).
    laughing house likes this.
  7. Nothing, but a 4 ohm load with the switch set to 8 might be bad. If pushed hard in this scenario, it will attempt to make more than 500 watts and may go into protect mode or possibly even blow up.
    Last edited: Apr 8, 2015
    karl_em_all likes this.
  8. middy


    Mar 14, 2007
  9. In 1974 Univox introduced their "Mobile Ohm" series. The U200B solid state head was rated at 210 watts R.M.S. and could be selected to accept 2, 4 or 8 ohm cabinets. And yes it is true that watts are not subject to emotional slant, but these were blistering Univox watts !
  10. Short on money, your last concern is some power limiting doohicky.
  11. seamonkey


    Aug 6, 2004
    some Carvin amps have a 2 ohm switch, it lowers the rail voltage to allow the amp to be stable at 2 ohms, there is not an increase in power, a slight decrease actually.
  12. pauljude


    Mar 6, 2014
    oswego ny
    The new HYdrive Hartkes have the 4/8ohm switch...I have two 2 x12's with that feature
  13. friendlybass


    Jul 19, 2012
    It has 2 output transformers, like a tube amp. You get 500 watts at 4 or 8 ohms.
    Any solid state amp will do 8 or 4 ohm setups, but you lose wattage at higher impedance.
  14. The Orange Terrors are class D output amps, NO output transformers.
  15. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    Since you're in the UK, older Marshall tube amps have a 4, 8, 16 ohm impedance switch.
  16. Wow! I got to look into this switch thing. All of the amps I ever used must have been really hightech special amps, because when I plug in an 8 Ohm cab it performed 8 Ohms. When I plugged in two 8 Ohm cabs it went to 4 Ohms all by itself. :eek: Witch craft I say.
    agedhorse and beans-on-toast like this.
  17. FFTT


    Mar 15, 2009
    Reeves 225 or 400 2.4.8 Ohm selector switch.
    Also available with international power supply on special order.
  18. Dave W

    Dave W

    Mar 1, 2007
    White Plains
    I would not base a purchase off of that feature.

    You and your friend are buying this together? How is that going to work?
    S-Bigbottom likes this.
  19. TrevorOfDoom


    Jun 17, 2007
    Austin, TX
    Almost all amp heads can switch between 4 & 8 ohms. Only the TerrorBass will supply ~500 watts no matter which impedence. This is awesome.

    However, it shouldn't be used to decide which cab/cabs you choose.
    If you want a 4ohm 1x15, you'll run into trouble as soon as you play a room where the one cab isn't enough. You can't add another cab as you're already at your impedence limit.

    When buying small, stackable cabs (anything from a 1x10 to a 4x10), go for 8 ohms so you can add to them.
    Large cabs that don't need stacking (2x15, 4x12, 6x10, and 8x10) are fine at 4ohm because you don't need to stack them.

    Lastly, if you weren't satisfied by the TB500, you shouldn't buy it just because of a fun feature. You'll be able to switch impedences all day long but never love your tone. That's a bad trade-off.
  20. DWBass

    DWBass The Funkfather Supporting Member

    I had a Yorkville XS-800 that switched internally and could accept an 8/4/2 ohm load. Was weird though. 600w@8ohms, 800w@4ohms and back down to 600w@2ohms. The amp was doggone loud though!

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