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This section needs a FAQ...

Discussion in 'Amps and Cabs [BG]' started by Malus, May 22, 2005.

  1. Malus


    Feb 20, 2005
    San Antonio Texas
    I have a buddy who has a high-end guitar tube amp - he was going to use with his new bass. His other friend told him to get a bass amp because he would blow his guitar amp's speakers with the bass.

    This doesn't make any sense to me - particularly since his bass has passive electronics. How much more energy could a passive bass pick-up generate than an active electronics electric guitar? I've recorded guitars and basses direct-in to mixing boards and haven't noticed much if any difference in levels; however the music being recorded did not have a great amount of dynamics.

    If you overdrive any amp you have the possibility of blowing the speakers attached to it - but I tend to think that wouldn't be any difference between a guitar and a bass in that regard. I've used a 10 watt practice guitar amp before I got my bass combo amp without any problems (of course, I didn't kick the gain and volume up to 100% either - and neither did I with the guitar).

    Does anyone know the definitive answer to this question? :confused:
  2. 44me


    Jun 17, 2002
    Bedford, NH USA
    You're right - the only thing at risk of being damaged is the speaker.
  3. MJ5150

    MJ5150 Moderator Staff Member Supporting Member

    Apr 12, 2001
    Olympia, WA
    I just wanted to say something in response to your thread title.

    I find that when I do a search for the keywords in my question, that I get all kinds of excellent info, and answers.

  4. Malus


    Feb 20, 2005
    San Antonio Texas
    I just noticed that the Effects section had a FAQ - and the AMPs section did not. FAQs contain the most definitive information on the subject so the users don't have to wade through years of opinions and arguments. Where things are in flux and there is no definitive answer - then the search capability is there for that purpose. Where questions have a solid scientific basis (which I believe this one does) then a FAQ can serve nicely.

    While searching is nice - finding an answer to a common question without cluttering up the message boards, or conversely wasting 2 hours trying to locate that pearl of wisdom is better. This is my subtle - or maybe not so subtle hint that maybe this section needs a FAQ bookmarked at the top of the forum... :cool:
  5. illidian


    Jul 2, 2004
    I believe IvanMike made one. Search for "FAQ" and you may find it.

    Maybe I'm just crazy?
  6. Malus


    Feb 20, 2005
    San Antonio Texas
    I guess that goes to the root of the question - is there a difference in the output of a passive bass vs. a passive guitar electronics?

    All things being equal (amp paired with speakers that are rated to handle the amp's power) - I wouldn't think it would be any easier to blow a combo guitar amp's speaker than a combo bass amp's speaker - assuming the same settings for gain and volume?
  7. Malus


    Feb 20, 2005
    San Antonio Texas

    I found his 'Ohm FAQ' - it doesn't quite answer my question - although there is a clue:

    He mentioned that guitar amps are normally rated at 16 ohms - whereas bass amps are rated at 4 or 8 ohms.

    More resistance (ohms) means it takes more energy to power the speakers - which would indicate that a guitar amp actually is safer than a bass amp in terms of potentially blowing speakers! (this assumes in both cases that a combo amp cabinet has speakers that are paired with it that are rated to handle the wattage and ohms matching...)

    Unless I am getting it all wrong...
  8. 44me


    Jun 17, 2002
    Bedford, NH USA
    The difference in output between a passive guitar and bass is similar. There's more difference between a guitar with a weak pickup and one with a strong one.

    Bass tends to be a little harder on speakers than guitar. Guitar speakers are generally designed for open back cabs and have a stiffer mechanical suspension. Most bass speakers, on the other hand, are designed for ported cabs and have a much more compliant suspension. This design difference along with a bass’s lower frequency makes it much easier to bottom out a speaker and damage it. The ported cab also puts a lot of stress on the speaker at the frequency that the port resonates, which can cause cone damage.
  9. I'd like to nominate myself for Amps FAQ duty. I promise not to be too biased towards Ampegs which we all know to be the greatest amps ever built of course.
  10. James Hart

    James Hart

    Feb 1, 2002
    Endorsing Artist: see profile
    a bass cannot damage a guitar tube head. The issue is that the lower frequencies of the bass can be too much for the speakers to handle. The Guitar speakers are what *can sometimes* be ruined. Many bassist pro and not have played loud and low through guitar gear over the years. I did for a while too.
  11. Joe Beets

    Joe Beets Guest

    Nov 21, 2004
    I think we need one. And it shoud start with "The Pros and Cons of Combo Amps"!! ;)
  12. Jack


    Sep 6, 2003
    Newcastle, UK
    Nobody noticed the Amps FAQ stickied at the top of this forum?
  13. Jazzin'

    Jazzin' ...Bluesin' and Funkin'

    Yeah...wasn't it always there?
  14. IvanMike

    IvanMike Player Characters fear me... Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    i guess not.......... :rolleyes:

    anyhow, the weak signal in the chain will be the guitasr speaker.

    lots of guys have gotten away with running bass thru guitar speakers but guitar speakers are for the most part not designed to handle the amount of energy the bass can deliver in the low end. I've seen many a guitar speaker torn to shreds by using a bass with it.
  15. Joe Beets

    Joe Beets Guest

    Nov 21, 2004
    But is that "Pros and Cons" thread in there?
  16. IvanMike

    IvanMike Player Characters fear me... Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    yup it sure is, with all of its TOF intact. ;)
  17. Bass requires lots of air movement.
    You need big drivers, or small drivers capable of moving a long distance safely. Cabinets have to be tuned precisely to squeeze bass out of small cabinet.

    Guitar speakers aren't designed to move a long distance (long excursion) cause they don't have to for guitar. Guitar speakers are also small. Guitar cabinets are designed to be midrangey, not emphasize the bass. So it will sound very crappy, tinny.

    You won't burn the speakers out, you'll bottom them out.

    Added bonus: Since it sounds tinny, you'll turn up the bass knob to make it sound better, which is like pouring gasoline on burning speakers. Just takes the basic problem and exaggerates it.

  18. Chiba


    Mar 11, 2005
    Guitar amps are not necessarily 'normally' rated at 16 ohms. I have 3 guitar amps right now, a Marshall head rated 4-8-16 switchable, a Koch head rated 4-8 switchable, and a Fender combo which is 4 ohms only (8" speaker).

    All kinds of amps have all kinds of output ohmages possible, and many guitar amps - ESPECIALLY heads - are switchable between 2 or 3 choices.

    What you pretty much *never* see is a guitar amp (tube amp anyway) that's rated for performance at 2 ohms, which I've seen on some PA and bass heads.

    Besides - as others have said, it's not the heads/amps that are the 'problem' with running a bass through a guitar head - it's that guitar speakers aren't designed to handle the low frequencies.

    Back in 'the day' lots of Brit bass players used the same kinds of amps - Marshall & Vox - that guitarists were using. Marshall especially was a popular choice, as was their 4x12 cab, for bass players.

  19. That's the first thing I checked when I saw the title of the thread. Maybe there should be a sticky notifying people of the other sticky.


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