Clipping my power amp

Discussion in 'Amps [BG]' started by LGT, Oct 2, 2013.


  1. LGT

    LGT

    Joined:
    Feb 9, 2010
    Location:
    North Carolina
    Hey all! I've been running a Sansamp RPM with a Crown XLS1000 into a Bag End S15 for about a year now, and it's been a great sounding rig so far. Recently however, It's gotten to the point volume-wise at band practices that the Sansamp starts to overdrive the Crown a bit, so I have a few questions as to what you guys would recommend.

    1. I'm currently running just one channel of the Crown at 8 ohms. Would bridging it be a possibility? It mentions bridging the the channels at 4 ohms in the manuel, but not at 8, so I'm not sure if that's an okay thing to do. I know that more speakers is almost always a better way to get more volume, but I can't really afford another Bag End right now, and would rather not have to carry two cabs to practice.

    2. Are we just too loud? My drummer is a tad heavy handed, but it doesn't seem too excessive to me.

    3. We practice at my drummers house in a room that's probably about 15' by 25'. Would anything as far as positioning in the room make a difference? I know it's a long shot, but heck, why not?

    Thanks

    edit: just by the way, this is a power trio
  2. intheory

    intheory Supporting Member

    Joined:
    Nov 17, 2009
    Location:
    SW Florida
    Sounds like you might have some frequency clashing going on, as well as volume wars? Does the guitarist pump out a lot of lows? What is the guitarists rig?
  3. Downunderwonder

    Downunderwonder

    Joined:
    Aug 26, 2009
    Location:
    New Zealand
    Smashing away in a 15x25 room is a great way to go deaf. It's not lack of power making you too quiet, it's everything is too loud.

    Start with elevating all your cabs to put them in the faces of their owners. That'll drop everything down and drummer should follow suit.
  4. MVE

    MVE Supporting Member

    Joined:
    Aug 8, 2010
    Are you sure you are not just overdriving the input on the Crown?
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  6. LGT

    LGT

    Joined:
    Feb 9, 2010
    Location:
    North Carolina
    He's just running a small vox valvetronix combo.

    Cool, sounds like a place to start for sure. Just a note, we do wear earplugs, but I guess that shouldn't be necessary for practice.

    The little LED meter on the crown is hitting red, I'm not sure which that would be.
  7. Jeff Scott

    Jeff Scott Don't just TalkBass - PlayBass! Supporting Member

    Joined:
    Apr 11, 2006
    Location:
    NE Ohio
    I'd go with #2!
  8. Downunderwonder

    Downunderwonder

    Joined:
    Aug 26, 2009
    Location:
    New Zealand
    Earplugs shouldn't be necessary for practice but most drummers in garage rock bands can't play that quietly while maintaining energy. Even if they can there's usually a guitard playing too loud and blaming the drummer. Stick with the earplugs.
  9. LGT

    LGT

    Joined:
    Feb 9, 2010
    Location:
    North Carolina
    That does sound a bit like my drummer.

    So it sounds like the consensus is to just turn down a bit and try to force my him to play a bit quieter. Thanks guys!
  10. MVE

    MVE Supporting Member

    Joined:
    Aug 8, 2010
    I just checked the manual for your poweramp and the meter lights are output signal. So, no it does not sound like input clipping.

    Yes, you should try bridging first. But don't expect a miracle and keep an ear on your cab as you might start to find it's max.

    If bridging does't do the trick, you might want to start shopping for another S15 to pair up and star moving some more air.

    Turning down is never an option. If the drummer is too loud, it is imperative that you continue to AMP UP, until he cant even hear his crash cymbals. You will only know you have enough power when the drummer starts asking you to turn down. :)
  11. tbirdsp

    tbirdsp Supporting Member

    Joined:
    Sep 18, 2012
    Location:
    Omaha, NE
    What MVE said. One side of the XLS1000 at 8 ohms is only putting out 215 watts. If you bridge it into 8 ohms it's 700.

    Bridged into 4 ohms it's 1100.
  12. Downunderwonder

    Downunderwonder

    Joined:
    Aug 26, 2009
    Location:
    New Zealand
    Ugh. Next the guitar player will get a stack. Besides, even if the amp can't quite stress the cab as it is, bridging will only make it fractionally louder but greatly increase the chances of blowing it up. All to pulverise a 15x25 room.
  13. Vince Klortho

    Vince Klortho

    Joined:
    Jan 8, 2013
    Location:
    Squierville, California
    If the amp can be bridged into 4Ω then it can also safely operate at 8Ω. However, you need to be careful if you are going to drive just a single 15. You could easily smoke it with that much power.
  14. Finbase

    Finbase

    Joined:
    Oct 12, 2010
    Location:
    Espoo, Finland
    Hi LGT!

    I had very similar problems with my Crown XLS 2500, and some witty folks here helped me out!

    I think your issue is not that much due to ohm loads. I started the thread on the issue, and the conclusion was that one needs a "special" bridged mono cable, since the Crown XLS utilizes it (like the one that Ampeg SVT-4 uses). The regular speakon cables just don't work properly!

    Here's what the Crown manual says:

    Bridge-Mono Mode
    "2. b. If using a Speakon® connector, connect the positive terminal of the speaker to 1+ and the negative terminal to 2+.
    Plug the connector into the Channel 1 output only"

    So your speakon cable should have the following kind of wiring/construction:
    -1+ 2+ on the amp end of the amp-cab1 cable and 1+ 1- on the cab end (bridged mono speakon-cable)

    -1+ 1- on both ends of the cab1-cab2 cable (so if you're running two cabs, just a regular speakon cable!)

    Please see the link, you'll get all the necessary information there. And if you like, just send me a PM, I'm glad to help you, if you need!!

    http://www.talkbass.com/forum/f15/crown-xls-2500-monique-issue-1016341/

    I'm playing with really heavy handed drummers, and I'm finally glad to make their ears bleed! :D

    Cheers!

    Finbase
  15. 1958Bassman

    1958Bassman

    Joined:
    Oct 20, 2007
    Your ears will be leaving you soon, so it really won't matter if you bridge the amp, or not.

    If an amp's manual indicates that it can be bridged into a 4 Ohm load, it will be fine with 8 Ohms.

    If you're trying to get more output, increase the mid-bass. It will definitely sound louder and you'll be able to decrease the low end a bit without sacrificing much of anything.
  16. MVE

    MVE Supporting Member

    Joined:
    Aug 8, 2010
    Seriously, I have never used a 1-15 that could "really" keep up with a rock band.

    Like I said, try bridging first, but start saving for a twin brother for that S15.

    That is really what you need.
  17. Downunderwonder

    Downunderwonder

    Joined:
    Aug 26, 2009
    Location:
    New Zealand
    At the other extreme, some of the pro's on here rock out live onstage without the need for earplugs.

    If you're not playing screaming loud metal styles 1x15 puts out ample volume to deafen, why anyone would need more than that in a garage is simple excess. Been there with a Marshall stack, it took awhile but eventually he accepted the fact that his was too loud for what mine could do and we settled into a good mix. Still deafening.

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