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DI's=Preamps?

Discussion in 'Amps and Cabs [BG]' started by Stu L., May 30, 2002.


  1. Stu L.

    Stu L. Supporting Member

    Nov 27, 2001
    Corsicana, Texas
    Are DI's and preamps the same thing? Can you take something like a SansAmp or MXR and use it as a pre? I am not happy with my Ampeg's built in preamp. Can I use these pedals for that reason, then one day with a power amp?
     
  2. jokerjkny

    jokerjkny

    Jan 19, 2002
    NY / NJ / PA
    IMHO,

    anytihng that allows you to go from high to low impedence cabling. in other words, from 1/4" to XLR or vice versa is a true DI box. most rack preamps allow you do go 1/4" to XLR so they're like "sorta" DI's.

    yet i could be naive... anyone else?
     
  3. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    NO, they're not the same thing. The main purpose of a preamp is to raise your relatively anemic instrument signal to a level where it can drive a power amp. A DI basically allows you to directly inject your signal into a mixer or recorder.

    Now, there is some overlap, in that many if not most good preamps also include a DI function, and some devices primarily marketed as DI devices may be able to put out enough level to be used as instrument preamps (? Avalon U5?, maybe SansAmp Bass Driver DI?).

    But you can't just pick up any old DI and assume it will work as a preamp. No passive DI will, and many if not most active DIs probably won't either, or at least not well. To find out if the devices you're considering will do what you want, either (1) call the manufacturer or (2) borrow some equipment and try it out for yourself.
     
  4. Stu L.

    Stu L. Supporting Member

    Nov 27, 2001
    Corsicana, Texas
    What about boxes like the MXR M80? Listed as a DI, but said to be able to be used as a preamp. I thought the SansAmp was about the same thing.

    So my Ampeg head has a preamp and a DI built in? It has an XLR out to run to the board, before the power amp.

    This stuff is confusing.

    So I guess that I need to be on the lookout for a device specifically labeled as a preamp?
     
  5. BFunk

    BFunk Supporting Member

    DI's convert an high impedence unbalanced signal to a low impedence balanced one. The signal level is usually mic level, which is lower than instrument level. Some DI's can output mic, instrument, or line level signals. You can drive a signal to an amp, console, or direct to a recording device depending on the level.

    A pre-amp converts a low level signal to a high level one. It usually also has some signal processing stuff like an eq. It usually puts out a line level high impedence signal. Some of them also put out a balanced low impedence signal like a DI does.

    Most high quality modern bass pre-amps can also act as a DI.
     
  6. Stu L.

    Stu L. Supporting Member

    Nov 27, 2001
    Corsicana, Texas
    So we've identified the beast. I don't need a DI, I need a preamp. I now understand that some good preamps include DI's. Thank you gentlemen (and any ladies that have looked).

    So, the eternal preamp question, "which one?"
     
  7. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    All heads have preamps built in, by definition. Every head is a combination of a preamp and a power amp. And yes, that XLR output from your head is a DI.
     
  8. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    You just gotta test drive as many as you can. I'd try Demeter, Kern, Alembic, Aguilar, SWR, and Eden for starters.