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Clipping Help

Discussion in 'Amps and Cabs [BG]' started by SonofDadBass, Oct 11, 2005.

  1. SonofDadBass


    Sep 12, 2005
    New Jersey
    400w 4ohm Hartke amp into a 400w 8ohm GK cab.

    Why would the amp head clip with the volume at 5?

    Is this a sign of something wrong?


  2. Eric Moesle

    Eric Moesle

    Sep 21, 2001
    Columbus OH
    Because you are not getting 400 watts using an 8 ohm cab with that setup, and I'm willing to bet you have the lows boosted and the mids cut? Talk to me . . .
  3. You are getting something like 250 watts using an 8 ohm cab. You're volume knob is relative to your bass guitar's ouput level. If you have a loud bass you will hit full power sooner on the knob than with a quieter bass.
  4. SonofDadBass


    Sep 12, 2005
    New Jersey
    Fellow bassmates,

    Actually lows are turned down, mids are in the middle (at 5) and the high are in the middle too. I turned down the lows in hopes of remedying the clipping problem but it still occurs every once in a while, usually in the middle of a song.

    I am concerned that maybe the amp is just not up to task, (I did buy it used and for cheap)

    My bass is a 1970s Univox P Copy.

    Thanks for the help,

  5. Could be clipping the input too, not the output. Is there a clipping light by the input gain knob, or a clipping indicator for the power amp, a compressor/limiter light that's going off, or are you just hearing the clipping?

  6. IvanMike

    IvanMike Player Characters fear me... Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    actually it's not all that uncommon for a lot of heads to start clipping with the master volume somewhere above the mid point.

    On most amps you'll have two volumes; the preamp gain, and the master volume. Both can clip. Typically players adjust the preamp gain to just under the point where it starts to clip. This will vary depending upon the output of your bass, how you set the active eq (if any) on your bass, and how hard you play. The active EQ can also cause the preamp stage to clip, but depending upon where the clip indicator (if any) is in the circuit, this may or may not trip the preamp clip indicator.

    After setting the preamp and EQ, players adjust the master volume to set the overall volume (duh). ;) Anyhow, in almost all cases, if the preamp is set to just under clipping most master volumes start to clip at right around one o'clock. Soem players adjust their preamps differently, and are able to turn the master volume all the way up, but that's not all that common.
  7. SonofDadBass


    Sep 12, 2005
    New Jersey
    Ok Mates,

    The amp head is a Hartke HA4000. All the settings were at 5 or below.

    On the right side of the amp there are three lights
    1 Power
    2 Protect
    3 Clip

    The red light was flashing for clip.

    I like the sound of the cabs and this amp head together. Previously for both gigs (I'm usually mic'ed or direct) and practice I had been using a 60w Fender combo amp. So this was the first real equipment purchase I have ever made. I paid the amount I was looking to spend, about 600 bucks for 2 new cabs and the used amp.

    Part of me finds this task of matching amps and heads and watts and ohms interesting, mysterious and mystical, perhaps like Bigfoot.

    The other part of me finds it frustrating and just wants to shoot him and drag his carcass into a museum.

    I play rock ala Sunny Day Real Estate. My main concern is that this amp is going to die on me mid-gig.

    What do you think?

  8. Given 250W@8 ohms, into 1 cab (whether its a 1x15, 4x10), if your band/drummer is on the loud side, you could be pushing this amp to its limits to keep up. There aren't too many cabs, even like schroeders, that would be able to really scream with only 250W input, unless its a tube head, or heavily compressed ss.

  9. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    If there's a master volume raise it and lower the pre-amp level; very often clipping indicators are tied to the level going through the pre-amp, not the power amp.

    You may need a bigger amp, you may not. The 400 watt rating of a cabinet only means that's how much power it will likely take without damage. It doesn't mean it will operate without distortion with that much power input. In fact, chances are very slim that it will take more than half power before crapping out. But going beyond that, there is almost no correlation between the wattage rating of a cabinet and its output capability, that being a matter of sensitivity and frequency response. It may well be that a cabinet with higher sensitivity and/or lower frequency response is what you need.
  10. SonofDadBass


    Sep 12, 2005
    New Jersey
    What would be potential results of connecting two 8 ohm cabs (400w and 200w) to the Hartke?

    Would that be further stressing the amp?

  11. You won't be stressing the amp by adding an 8 ohm cabinet. You will be able to turn the amp down to achieve the same volume, reducing the clipping issues. BTW it is my understanding that clipping isn't harmful to the amp, it is harmful to the speakers.
  12. BurningSkies

    BurningSkies CRAZY BALDHEAD

    Feb 20, 2005
    Seweracuse, NY
    I have a 3500, and I found that the pre starts to clip anywhere past 5 (either of the pres). I tend to run the main either full out or 75% of the way up, and have my pre down around 2 or so. Takes care of the problem nicely.

    I second the notion that you should use 2 cabs...but you shouldn't need to either.