Discussion in 'Amps and Cabs [BG]' started by bentem, Jan 29, 2003.

  1. bentem


    Oct 18, 2002
    Rockville, MD
    Two things-

    Does the ohm level affect sound quality?

    And if you have two cabs, each with a different ohm level, is that ok?

    Also, i was thinking about getting an Avatar speaker cabinet to play mw new amp through. Probably a 2x10 now, then save up for a 1x15 sometime in the future.
  2. Captain Awesome

    Captain Awesome

    Apr 2, 2001
    Does ohm level affect sound quality? No.

    If you have a mono amp, and you're using cabs with two different impedances, the higher impedance one will not get as much power as the lower impedance one.
  3. Petebass


    Dec 22, 2002
    QLD Australia
    The omhs thing is tricky. Get it wrong and you could blow up your amp.

    Maybe. We'll need more info...........

    What is the ohm rating of each cab?

    What is the minimum Ohms your amp will handle. It should be written on the back of your amp somewhere.

    Also is the amp tube or solid state?
  4. bentem


    Oct 18, 2002
    Rockville, MD
    the amp is solid-state, with a minimum impedince of 2 ohms

    I dont have the cabs, i just wasnt sure what cab to get
  5. Captain Awesome

    Captain Awesome

    Apr 2, 2001
    Assuming it's a mono amp, this what the load on your amp would be with various ohm configurations:

    8 ohm cab + 8 ohm cab = 4 ohm load
    4 ohm cab + 4 ohm cab = 2 ohm load
    4 ohm cab + 8 ohm cab = 2.67 ohm load

    If your amp can operate at 2 ohms, than you would be fine with any of those configurations.
  6. Petebass


    Dec 22, 2002
    QLD Australia
    Ok to get full power (watts) out of your amp, you'll be best to run a 2 ohm load. The best way to do this is to run 2 cabs of 4 ohms each. You could also run 4 cabs of 8 ohms each but this is probably not practical.

    You can run more than 2 ohms but the amp will push slightly less power. It's not as much of an issue as it sounds. You could run 2 cabs of 8 ohm each for a total 4 ohm load and it will work fine but it will be slightly softer.

    If you run an 8 ohm cab with a 4 ohm cab, the total load will be just under 3 ohms. Your amp can handle this load so it will work at pretty close to full power, but the 4 ohm cab will recieve more power than the 8 ohm cab.

    Things to keep in mind - Never ever run your amp at 1 ohm, it will blow. And Tube amps behave differently.

    Hope that clears it up.
  7. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    As it has been written, the cab's impedance won't generally affect sound quality...unless your amp is really weak or the cabinet has a weird impedance curve (the numbers that we discuss are nominal as the impedance varies wildly with frequency). I've heard of 4 ohm Acme cabinets causing Carving power amps to shut down...but that's another story.

    What are the power ratings of your amp at 8, 4 and 2 ohms? Most amps don't put out much more power at 2 ohms than at 4 ohms. If this is the case, you'd be better off going with 8 ohm cabinets as your amp will run cooler (a small power difference at 2 vs 4 generally means that the power supply inside your amp is working pretty hard at 4 ohms).

    Since it takes a doubling in power to increase the sound pressure level 3 dB (generally the smallest change that most people can hear), running two 8 ohm cabinets on your amp is what I would recommend.

    As for using cabinets of different impedances...the one with the lower impedance will get more power and depending on their relative efficiencies my be louder. At home I run a 4 ohm Acme B2 in parallel with an 8 ohm home brew 210 (Ampeg Celestions and a Fostex tweeter) and the home brew cabinet is louder because it's more efficient.

    BTW, I'm quite pleased with my Avatar cabinets (I have a B112 and a C15).

    Good luck!!!
  8. bentem


    Oct 18, 2002
    Rockville, MD
    The amp runs 300w at 2ohms, and 210 at 4ohms.

    About The avatar cabinets, How do you order them, or can you buy them in a store?
  9. TxBass


    Jul 3, 2002
    Frisco, Texas
    www.avatarspeakers.com. Order on-line or buy through E-bay, sometimes he offers them a bit lower--but it's hit and miss.