8 chanel 250 what mixer as opposed to amp

Discussion in 'Amps and Cabs [BG]' started by brentf, Dec 20, 2005.

  1. Hi all,
    I have noticed that you can pick up an 8 track powered mixer for a whole lot less than a dedicated bass head.
    Can someone please explain why.
    Would it be a good idea to use one as my amp, rather than fork out large sums of cash on a dedicated head?
    It gives so much more in the way of tone shaping as well as gives the option to run other instrumentsinto it as there are efectily 3 outputs vis: speaker L & R as well as monitor, which is driven by a separate amp.
    Comments please.
  2. bongomania

    bongomania Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    I've seen a wide range of prices for both categories of product. One isn't always cheaper than the other. On the other hand, most new 8-channel powered mixers are aimed at a beginner-level user, so the construction may be lower quality or lighter-duty than a similarly priced bass head. Typically the housing of a mixer is plastic, while often the housing of an amp head is steel. Also, there's the wattage to consider. Say your powered mixer puts out 250 watts; a 250 watt bass head is probably not going to be more expensive. But bass heads are usually more powerful than 250 watts, and more wattage usually means higher price.

    Another thing is that a high-volume producer like Behringer can whip out and move large quantities of general-purpose gear for cheap; while a smaller company (that maybe doesn't use sweatshop labor or crappy components), making a more specialized niche-market product like a bass head, can't afford to go so low on the price.

    On the other hand, if the wattage of a powered mixer is enough for your needs, and the sound and construction are good enough for you, and you want those extra channels, then go for it, it will work fine.
  3. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    One word: Quality.
  4. seamonkey


    Aug 6, 2004
    bongomania is right on point. Myself I use a non-powered mixer and a power amp.

    But I'll add in my opinion...

    When you look at a bass head, you'll find it's an amplifier coupled to a bass specific preamp.
    The amp part is nothing special. Power amplifiers are generic swap out commodities.

    The bass preamp part is specific for bass. With the knobs at 12 o'clock the preamp will have a curve in it's response. Player's often mistake this as a distinctive sound to the amp head. The controls on the preamp part are specific to a basses range.

    Mixer heads will tend to have a flat response at 12 o'clock, so you'll hear statements like "it sounds sterile", "it doesn't have punch", and the controls may not be specific to a basses range, so tweaking may not fix all players.

    In the end you'll probably want to get a bass preamp that is meant to tweak a basses sound. Because most of the "science" in a bass amp's sound is in the preamp - you'll find that bass preamps are expensive for what you get. Maybe as much as a powered head.

    Another alternative is just buying a good generic power amp and getting a "get by for now" preamp, like a stompbox unit (<$100) Later buy a higher end preamp. An extra preamp is always a good thing to have around. A good power amp is always good to have around also.
  5. doctec


    Mar 22, 2005
    Beaverton, Oregon
    One possibly issue when using a powered mixer as a bass amp is input impedance. Most bass amps have an input impedance of about 1 megaohms. Passive basses generally sound best when they're plugged into a high impedance input like this.

    The 1/4" input jacks on most mixers have a lower impedance and, in my experience, tend to make a passive bass sound a little, er, umm, constipated. This is less of an issue if you're using a bass with active electronics.

    The way to get around this -- if you want to use a powered mixer as an amp for a passive bass -- is to get a DI box and and use it to go into the XLR input instead of plugging your bass directly into the board.
  6. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    I wouldn't say that. A cheap powered mixer is probably using an IC output with a barely filtered anemic power supply. The only way you'll know how cheap it is is when the whole thing goes up in smoke in the middle of a song. At that end of the spectrum there's more cost in the potentiometers than the rest of the electronics put together, and with all the pots in a mixer that doesn't leave much money left over for such niceties as high grade power supply caps and discreet output devices.
  7. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    A friend of mine bought a complete PA system that included a really cheap powered mixer. One of his speaker cables developed a short, and he found out because the mixer began to smoke. In other words, the mixer had no short-circuit protection.
  8. seamonkey


    Aug 6, 2004
    this can happen with some bass amps also.
  9. I have a mixer I use for recording at my house. I plugged it into a small power amp and into my bass cab to see what it would be like. I have to say, it quite worked, but it sounded terrible. I plugged in my FX unit to it, and even though I hate modeling even that sounded better. If you are building a rig, it is better soundwise and costwise to get a head or a dedicated bass or mic preamp with a poweramp.
  10. Thanks for all the feedback guy's.
    Yep I didn't think about the pre-amp issue, which makes the whole exercise a little pointless, as you can get a good combo unit for the price of the two, and add another cab when necessary.
    Oh well I guess my practice amp project is going to take a little more time than expected. :(
    I was planning on using a head which I could use in my practice room with a small cab and use it with a big cab later.