Interesting little MAG fact

Discussion in 'Amps and Cabs [BG]' started by Nickthebassist, Mar 15, 2005.

  1. You can remove the entire amplifier! This means I can take it to Y-Rock and use it as a pre amp, so I get all my ashdown tone, just without the speaker. It won't damage it by not having a speaker plugged in will it?
  2. Kael

    Kael Supporting Member

    Dec 26, 2004
    Oklahoma City
    You could also just leave the power section installed and take a post EQ DI out to another amp/board. This will accomplish the same thing without requiring physical changes to your head.

    I seem to be experiencing deja vu here....
  3. Selta


    Feb 6, 2002
    Pacific Northwet
    Total fanboi of: Fractal Audio, AudiKinesis Cabs, Dingwall basses
    You can do this in most, if not every, amp. Usually just four screws/bolts and it's out.

  4. fraublugher


    Nov 19, 2004
    ottawa, ontario, canada
    music school retailer
    i wouldn't run it without the speaker plugged in .

    something about the load having no-where to go , i forget the technical explaination and too many past mishaps
  5. PunkerTrav


    Jul 18, 2001
    Canada & USA
    Yop, my Yorkeville BM400 combo is just the BM400H head screwed into a 1x15 cab. I like that I can take out the head and carry it seperately.
  6. That has always been my understanding, although I am unsure whether that relates to solid state amps to the same degree as it does to tube and/or hybrid units. :meh: :meh:
  7. Good to know that I don't need to be quite so paranoid about solid state amps.

    Thanks for clearing that up.

    :) :)
  8. Wish that were the case - my Ampeg SVT200 combo (4x10") is not so easy. I would love to remove just the head, but haven't seen how I would do so.

    Half the reason I'm posting this is because I hope someone can show me the way. :)
  9. Selta


    Feb 6, 2002
    Pacific Northwet
    Total fanboi of: Fractal Audio, AudiKinesis Cabs, Dingwall basses
    Well, there's something somewhere holding it there... look around for a few bolts/screws. May be behind the speaker too (internal), so you'd might have to look there.

  10. GREAT! This means I can take it to the festival as my pre amp, without the bulk of the amp with the speaker.
  11. Sonorous


    Oct 1, 2003
    Denton, TX
    I think having it on without it being connected to a speaker will damage it. It messes with the impedence... it'll be running with 0 ohms.

    I think.
  12. Warwick player

    Warwick player

    Dec 31, 2002
    Bucks, UK
    You will mess the Power Amp section if you unplug the speaker and play through it. The output would be seeing no 'load' or zero impedance. It needs to see some load, however, on some amps you can take the signal out after the pre-amp and eq, into a Power amp or into a PA.
  13. Nope...;)
    Not an issue for solid-state amps. They can be run with no speakers without any fear of damage.

    In this situation, the power amp actually sees an open circuit or ~infinity Ohms, not ~0 Ohms. The amp will produce output voltage but no current will flow and therefore no power will be produced. No problem. :D

    Different story for all-tube or any transformer-coupled amp. The transformer needs to be terminated with a proper load or bad things will happen.
  14. Warwick player

    Warwick player

    Dec 31, 2002
    Bucks, UK
    It is all dependent on how stable the amplifier is!

    You cannot say for certain that it will not damage the amplifier, likewise you cannot say for certain it will work!

    Let me quote another forum,

    There is no danger if there is no signal present, since the idling plate current and voltage are the same with or without a load connected. There would be problems, of course, if the amp was unstable without a load and began oscillating.;f=4;t=001037
  15. Selta


    Feb 6, 2002
    Pacific Northwet
    Total fanboi of: Fractal Audio, AudiKinesis Cabs, Dingwall basses
    Just to prove a point, I just did this. I unpluged my cab from my T-max, turned it on, plugged my bass in, put my settings where I do when I'm at a gig, played for 11 minutes. I then turned off the amp, pluged the cab in, and turned it back on. Not a single glitch whatsoever. I would say that in most cases that you can safely run with zero load. I remember doing something similar with my old Acoustic amp a few times as well.

    Edit: also, when you quote something, don't just quote the little bit that is on your side of an argument:
    As you can see, he states that the argument is for early solid state amps.
  16. Danm


    Sep 24, 2003
    Canberra Australia

    Idling plate current etc etc is referring to a tube amp.

    Totally prepared to be corrected if I'm wrong tho.

  17. Any amplifier that is unstable under no load is poorly designed. I can assure you that no commercially available amplifiers are unstable without a load connected. Even my class-A, 0 negative feedback amps are stable into an open circuit and these types of amps are prone to instability.

    Any sensible amp that doesn't have an output transformer (i.e. just about every solid state amp) will be just fine if ran with no load connected.
  18. BurningSkies

    BurningSkies CRAZY BALDHEAD

    Feb 20, 2005
    Seweracuse, NY
    A couple of months ago, I was playing a gig with my brand new bass, the first with active electronics for me. Well, about an hour into our 3+ hour stage time, I had blown out all 4 of the elderly 10" speakers in my cab. (my bad, the bass pushes much more low end as well as more overall gain)

    What did I do? I asked the sound guy to turn me up in my monitors, and turned the main all the way down on my Hartke 3500 and unplugged the cab...since the amp is set up to pull the direct after the pre and EQ. Worked fine....for the next 2+ hours. No damage, no problems, no load on the main outs.

    I still use the amp without any problems since.
  19. Nick you can safely run your solid state Mag amp with no speakers connected but a big warning please take note:

    If at any time while the amp is on and you havnt got a speaker connected do not under any circumstance connect a speaker to it while running as you will blow the power amp fuse or further damage in fact you will actually see a small spark - arc as you connect the jack into the cabinet !!

    I know this is unlikely but be warned so always turn the amp off before connecting or disconnecting the speaker load, how do i know as i blew my old MAG300H twice before i realised why it was happening and good old Ashdown fixed it under warranty both times great company service.

    Are you talking about the Y FRONT FESTIVAL ??