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Mixer to Boost Signal to Poweramp

Discussion in 'Amps and Cabs [BG]' started by brendio13, Feb 21, 2018.

  1. brendio13


    Nov 24, 2009
    Melbourne, AUS

    it have search but cant find a answer for my question

    i have a QSC power amp DCA 1622 power amp running Bridged 8ohms (1100watt)
    into a 600watt 2x10 8ohm cab.

    i have a bunch of pedals but not preamp as such

    i use only passive basses (1 pbass, 1 MM clone, 1 sterling sub)
    plug into my power there is just not enough to get the most out of the power amp.

    i could look at a preamp, but from what i have read, alot of them still wont provide the right amount of output to drive the amp.

    what i want to know if that if i have a little 5 channel mixer in which i plug my bass into and then run the output to my poweramp (pan left or right as i am only using 1 channel, would this help drive the amp more?

    i have a di that i use at the moment with a 20+db lift that brings the volume up but not sure thats the best option.

  2. Wasnex


    Dec 25, 2011
    Professional power amps need a line level signal. You DI brings instrument level up to mic level. Plug the DI into your small mixer and it should be sufficient to drive the power amp.

    Many power amps have switches that allow you to select the input sensitivity level. Sensitivity is the input level required to push the amp to full power with the controls wide open. Check the manual for the mixer and power amp so you know what level to use. +4dBu is common for professional equipment.
  3. brendio13


    Nov 24, 2009
    Melbourne, AUS
    thanks @biguglyman. i have seem a few people note that these are a good option.

    @Wasnex ill have a look at for the manual of the poweramp and see what i can fine.

    im even looking at maybe get a preamp to just make it easier but again, i see alot of people noting that they are still hard to match the impedance of the poweramp to ensure it can run full
  4. Wasnex


    Dec 25, 2011

    Either a preamp or a mixer will be fine. The DCA 1622 does not have switchable sensitivity. 4 ohm sensitivity is listed as +3.2dBu and 8 ohm sensitivity is listed as +3.9dBu. This is the minimum output the source must be capable of producing to drive the 1622 to full power. Professional equipment is generally setup to run a nominal +4dBu signal so your amp is set up for pro level. The Art Tube MP has plenty of output. Max output is listed as +28dBu (XLR), +22dBu (1/4").

    You don't need to worry about the impedance. The input impedance of the amp is designed to be much higher than the output of the device used to drive it. Google impedance bridging for the explanation.
  5. basscooker

    basscooker Commercial User

    Apr 11, 2010
    cincy ky
    Owner, ChopShopAmps
    I recommend switching the power amp out of bridged mode when you have something that properly pushes the input.
    Al Kraft, BassmanPaul and biguglyman like this.
  6. BassmanPaul

    BassmanPaul Inactive

    I doubt if the 2x10 cab. the OP has will handle 300W of bass frequencies in the real world. Just running into one channel of the power amp makes more sense from a safety perspective.
    Zooberwerx likes this.
  7. brendio13


    Nov 24, 2009
    Melbourne, AUS
    thanks for the replies
    @Wasnex great. i have just had a mate offer me a Behringer Ultragain MIC100 which im hoping can do the same job as the ART MP

    @basscooker @BassmanPaul cab is only a Behringer 2x10 ultrabass BB210
    i run it bridged just for the head room on the power amp i guess.
    i currently run the power amp about 50%-75% max, but with the existing pedals i have, it just seems so quite
    hope this MIC100 can get that up and get them thump.
  8. BassmanPaul

    BassmanPaul Inactive

    Even more reason not to bridge. The position of the level controls has no bearing on the amount of power that the amp can give. Even almost off the amp can supply it’s maximum power is the input signal is large enough!

    If you are needing more volume increasing your driver count trumps boosting power every time. To increase volume by two you’d need to increase power by ten!
    Wasnex likes this.
  9. Wasnex


    Dec 25, 2011

    I agree. One side of the DCA1622 is likely to have more than enough power to completely destroy your 210. Using bridge mode just increases the odds of having a destructive accident.

    The Behringer Ultragain MIC100 should work fine for you purpose. It's set up to function as a DI so the 1/4" input will accomodate instrument level. Here's a link to the manual if you need it. https://static.bhphotovideo.com/lit_files/84912.pdf
  10. BassmanPaul

    BassmanPaul Inactive

    Or one of the ART TubeMP units.
  11. brendio13


    Nov 24, 2009
    Melbourne, AUS
    thanks heaps @BassmanPaul & @Wasnex. with taking it out of bridge it will only supply 300w into a 600w cab.
    ive always read that its better to have more (1.5x) power from the amp to the cab.
  12. Wasnex


    Dec 25, 2011
    The 600 watt rating of your cab is probably extremely optimistic and related more to the thermal ratings of the drivers than their mechanical limits. I would be extremely surprised if the cab can handle 300 watts much below 100 hz. Most likely the driver will exceed excursion limits and incur damage.
  13. DigitalMan

    DigitalMan Bring Back Edit/Delete Supporting Member

    Nov 30, 2011
    Bay Area, CA
    Most preamps these days do a fine job of feeding power amps. Read the specs in advance if you’re in doubt.

    I happen to use a Rane line mixer ahead of a power amp, but that’s primarily to be able to use multiple sources either alone or together.
  14. BaileyMan

    BaileyMan Supporting Member

    Jan 8, 2012
    San Francisco
    Based on the replies I'm not entirely sure what you're looking for. Are you looking for just a boost type of pedal to increase output of your passive basses?

    I built a clean boost with about 4 electrical components that is transparent and gives me a hefty signal boost. All I'm saying is that if you're only looking to increase the output from your bass, you can get by with small, simple, and inexpensive.
  15. brendio13


    Nov 24, 2009
    Melbourne, AUS
    @BaileyMan im confusing myself now that i think about it.
    basically my passive basses plugged into my current D.I just doesn't have any loudness to it
    that would be due to the output lvl, so a clean boost would be fine

    @Wasnex so to have it back in stereo mode would be safer and once i have a higher input lvl into the amp it should be plenty loud enough?
  16. JRA

    JRA my words = opinion Supporting Member

    yes. it will work. :thumbsup:
  17. Zooberwerx

    Zooberwerx Gold Supporting Member

    Dec 21, 2002
    Virginia Beach, VA
    Why don't you just buy a proper bass preamp (rackmount) and be done with it? Here's the best thing going in the classifieds:

    For Sale - Yamaha PB-1 preamp

    If you going for a line-level signal, do it right.

  18. DigitalMan

    DigitalMan Bring Back Edit/Delete Supporting Member

    Nov 30, 2011
    Bay Area, CA
    The thing that is used to boost an instrument or mic level signal to be suitable for a poweramp is a preamp. Whether that preamp is embedded in a mixer, bass preamp, studio preamp, etc, doesn’t really matter. A Mesa Subway preamp floor pedal, a Sansamp rackmount, an Avalon U5, a 1U line mixer, or a 64 channel recording desk can all get the job done. No matter what device ends up solving the problem, there will be a preamp inside it somewhere.
    Wasnex likes this.
  19. Wasnex


    Dec 25, 2011
    @Wasnex so to have it back in stereo mode would be safer and once i have a higher input lvl into the amp it should be plenty loud enough?[/QUOTE]

    Yes, and if it is not loud enough, you need more speakers to handle the power.
  20. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

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