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Mag 300 + Mega Diesel 4x10 Distortion Question

Discussion in 'Amps and Cabs [BG]' started by jonnychicago, Apr 14, 2006.


  1. jonnychicago

    jonnychicago

    Mar 20, 2006
    Chicago
    hey everyone,

    this is my first post, though i've been a reader/admirer of your insights for the past few weeks.

    anyway my question is this:

    i'm running

    (2 week old) Ashdown MAG 300r
    (used) Mesa Diesel 4x10 8ohm 600 Watt Cabinet
    Fender MIM Precision w/ Reverend 8.7k Pickups



    i am using the eq (mostly all at 7 with a little bass boost), along with bright and deep options, with input about half way up. volume is all the way on my bass.

    when i turn the volume to a level that will be usable in most gig settings with a rock/punk band, i get distortion when i hit the strings aggressively with a pick. when i hit them normally, there is no distortion.

    is this normal overdrive coming from the amp? could it be something blown in the cabinet? am i "clipping" the amp by doing this, and if so, could i be damaging the amp/cabinet?


    any help at all is appreciated!


    jonathan
     
  2. joelb79

    joelb79

    Mar 22, 2006
    Lansing, Michigan
    Sounds like one of two options are happening.

    a) you have hit the limit of the internal power amp and you are producing a distortion that is called clipping. This is VERY dangerous for your horn tweeter, your 10's should be able to handle it for a while without issue. Solution is to buy a new head that handle the wattage your "sound" requires.

    b) you are running the input channel too high. This is why you hear clipping as you play harder but not softer. You are basicaly exceeding the limit of the preamp, while the power amp is effectivly "clean". In this case, you want to use the active input, and set the level to a decent level, while running the master volume higher than you have been, effectivly clearing the
    problem.
     
  3. jonnychicago

    jonnychicago

    Mar 20, 2006
    Chicago
    joelb,

    thanks for the help. i did turn down the input volume and got a cleaner tone. the only problem now is volume.

    would it be beneficial to buy a second 8ohm cabinet to effectively use all 300 watts at the 4 ohm capacity?

    or is it possible to disconnect the tweeter (or put the tweeter volume in the back of the cabinet to -25db) in the event that i need to push the power amp?
     
  4. chaosMK

    chaosMK

    May 26, 2005
    Albuquerque, NM
    Hi-fi into an old tube amp
    I would lower the gain quite a bit on your amp and use the master to control the volume. The input gain on the MAG is pretty sensitive. I had a similar problem, and that solved it.
     
  5. v-12

    v-12

    Mar 3, 2005
    FL Panhandle
    altouhgh i'm not too sure bout disco'ing the tweeter, adding a second cab would help, but 300 watts is not enough for playing "gig level" without pa help, or wouldn't be near enough for me; bur of course ymmv. i'd get a power amp with some more power, and use your ashdown as a pre. a diesel 4x10 with the right amount of power should be enough to cover most ANY gigs.
     
  6. anderbass

    anderbass

    Dec 20, 2005
    Phoenix. Az.
    (1) If you stop boosting the bass so much, your amp should be both cleaner and louder. Adjust your E/Q for good strong low-mids instead of super-boomy lows.
    (2) You could add a cab, or maybe rewire yours to 4ohm. Elevating or tilting the cab, can also help you hear yourself much better on stage.
    (3) Try all the horn-switch positions, including my favoite: off
     
  7. joelb79

    joelb79

    Mar 22, 2006
    Lansing, Michigan

    Mine too ;)

    Did you try putting the master volume at maximum, and using the pre-amp gain for your main volume level?

    Try the 575w version of the evo, you should be much better off. Either that, or invest in an amp that puts out 350w to a 8ohm load.

    Be flea, use a GK RB1000/1 and you'll be fine. They are not tooo expensive.
     
  8. dave_bass5

    dave_bass5

    May 28, 2004
    London, UK.
    After two years of giging mst weekends my MAG300 C-115 started to distort (or clip, im not sure of the difference) at anything past half on the master. it not the speaker as i used that part of the combo with my ABm and it was fine. its wasnt the input stage as i ran the signal out of the line out in to my ABM's power stage and it was fine so im guessing iits the MAG power stage. its in for repair now but i havent heard anything yet.
    Just wanted to point out that with the MAG (and ABM i think) the EQ effects the input level. the VU is post EQ so if you are running it with a lot of bass it could be over loading the input stage, i dont find the VU very accurate.
    Must admit though that i used to run it quite high and didnt have a real problem untill last Dec
     
  9. popinfresh

    popinfresh

    Dec 23, 2004
    Melbourne, Aus
    Personally, I think 7 on all EQ's with bass AND bright switches engaged is too much. If you lower everything (including gain) and use your master to control volume more you should be a bit better off.
     

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