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Using a head without a cab

Discussion in 'Amps and Cabs [BG]' started by ozellman, Jun 9, 2003.


  1. ozellman

    ozellman

    Jan 6, 2003
    Sweden
    Does anyone know what happens if you run a mosfet powered head without a speaker attached to it? Will I blow the fuse, overheat the amp or will nothing happen? I'd like to use my EBS head in studios with the need to lugg around a cab. I just need the preamp section and I will use the balanced DI output so making sure the volume is turned down all the way wouldn't be a problem if that helps. Some peope I've talked to says it won't be a problem and others say it will. Does anyone know?

    Ozellman
     
  2. FretNoMore

    FretNoMore * Cooking with GAS *

    Jan 25, 2002
    The frozen north
    Best bet is to send a mail to the EBS guys at ebs.sweden@bass.se, I've always gotten quick and helpful replies, or even better call them at +46 8-735 00 10.

    Today is a holiday in Sweden, so perhaps they won't reply until the next few days.


    EDIT: Ber om ursäkt, hann inte se att du är svensk. :)
     
  3. Craig Garfinkel

    Craig Garfinkel

    Aug 25, 2000
    Hartford, CT
    Endorsing Artist: Sadowsky Guitars
    I don't know about EBS, but I can tell you I often use my Aguilar DB750 in the studio sans speakers. Yes it's an extremely heavy DI to be dragging around, and if I had a spare $500 I'd pick up the Aggie DI...but it sounds great.

    I've never had a problem. I'm no expert, but I'd be truly surprised if the lack of connected speaker cabs would affect any type of amp head.
     
  4. FretNoMore

    FretNoMore * Cooking with GAS *

    Jan 25, 2002
    The frozen north
    Any type of modern head, at least. Most are protected against shorts, no load, etc, so I also believe it will be OK, but a quick phone call to EBS to make sure can't hurt.
     
  5. ozellman

    ozellman

    Jan 6, 2003
    Sweden
    Thanks guys. I've already sent EBS an e-mail so I'll wait for the official reply.

    Ozellman
     
  6. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    My understanding is that it doesn't hurt SS amps, but it can hurt tube heads to run them w/o a load.
     
  7. ozellman

    ozellman

    Jan 6, 2003
    Sweden
    It's what I've heard from other sources as well.
    The theory is that if you don't connect a speaker, there will be infinite resistance as there will be no connection between + and - as there normally is throught the speaker. Infinite resistance means that nothing will happen. Shortcuts (connecting + directly with -) are very harmful though as that will mean no resistance at all which will cause melt down of the transistors. I've heard some (at least one person) say that running SS heads without a speaker is harmful though which is why I'm checking with you guys and with EBS.

    Later

    Ozellman
     
  8. steve-o

    steve-o Guest

    Apr 17, 2002
    uummm....my old trace head was ran with out a speaker and boom...gone....
    the tech said that the speaker out was also a ground...so no ground....opps...(damn singer)
    now if it has a di...i don't see a problem....
    atleast not on my swr...

    steve
     
  9. ozellman

    ozellman

    Jan 6, 2003
    Sweden
    While investigating this I searched through some of the well known manufacturers' sites. I found that SWR explicitly states that it's possible to run their heads without speakers connected unlike most amps (their words). Neither Ashdown, Ampeg nor EBS even mention what happens if you do it and they certainly don't say you shouldn't.

    I'll post back once I find out from EBS.

    Ozellman
     
  10. JMX

    JMX Vorsprung durch Technik

    Sep 4, 2000
    Cologne, Germany
    the speaker has nothing to do with ground...
     
  11. Fishface

    Fishface

    Jul 26, 2002
    Denver, Colorado
    My understading is that if it is a tube power section it requires a speaker load. But, if it is a solid state power section it is OK.

    But I would always check with the manufacturer, especially if it is your only head and/or it is an expensive head.
     
  12. Johnny BoomBoom

    Johnny BoomBoom Supporting Member

    Jun 8, 2001
    Glasgow, Scotland
    I've used my Trace head before purely as a DI in the studio...worked OK!
     
  13. steve-o

    steve-o Guest

    Apr 17, 2002
    i should have explained this better...he plugged it in and was trying to get sound out of it with nothing hooked up to it....nothing!!! what a .......... not evan a sorry......uuuggghhh..
    it burnt out the power section...

    steve
     
  14. Eric Cioe

    Eric Cioe

    Jun 4, 2001
    Missoula, MT
    I can run my gk with no load and it's fine.
     
  15. my understanding of it is that if your power amp section is tubes then you CAN NOT run it without load but if it is solid state you can. The preamp doesn't make a difference.

    But anyway contacting EBS is the best thing you could've done anyway.
     
  16. ozellman

    ozellman

    Jan 6, 2003
    Sweden
    Thanks again everybody for your thoughts. I talked to the Technical Director of EBS today and he says that there are no problems whatsoever with running the head without speakers. Even if I crank the volume to 11 (which is possible with EBS heads :lol:), nothing happens as the power amp section is Mosfet based.

    Later

    Ozellman
     
  17. FretNoMore

    FretNoMore * Cooking with GAS *

    Jan 25, 2002
    The frozen north
    Great! Thanks for sharing.
     
  18. Eric Cioe

    Eric Cioe

    Jun 4, 2001
    Missoula, MT
    Why do they go to 11? Shouldn't they just make 10 louder? :D
     
  19. ozellman

    ozellman

    Jan 6, 2003
    Sweden
    I think it's originally a joke from the Spinal Tap movie.

    Ozellman
     
  20. HeavyDuty

    HeavyDuty Supporting Curmudgeon Staff Member Gold Supporting Member

    Jun 26, 2000
    Suburban Chicago, IL
    You've gotta love a company that makes their heads go to 11...