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MIC PRES AND DIRECT BOXES

Discussion in 'Recording' started by Jetmonkey, Jun 12, 2006.

  1. Jetmonkey

    Jetmonkey Guest

    Wondering if anyone has any tips on mic pre's and direct boxes. specifically, if i can use a good mic pre (tube perhaps) to function as a direct box as well, and vice versa.

    recording analog to tape.

    Thanks!
     
  2. RemyRAD

    RemyRAD Well-Known Member

    Jetmonkey, the only important factor when wanting to use a microphone preamplifier as a direct box is that the direct input should not load down passive guitar pickups, i.e. at least one million ohms input impedance and NOT 47 -50,000 ohms input impedance. That's adequate for active preamplified pickups and electronic keyboard instruments which have low impedance " emitter follower" output sections. So those load just fine into 47,000 ohm input impedances.

    Just beware that many microphone preamplifiers feature "direct input" for " musical instruments" that are not really adequate for passive electric guitar pickups. Just the low level amplified types that are powered.

    Generally tube type inputs, like their electric guitar amplifier brethren, are usually one million ohms input impedance or higher. Bipolar transistor input devices, like used for microphone preamplifier's, NEVER have input impedances higher than 47,000 ohms. With transistors, the only ones that have input impedances as high as a tube type are Field Effect Transistors or "FET's". So check your specifications when shopping.

    Prices and specifications subject to change without notice.
    Ms. Remy Ann David
     
  3. Jetmonkey

    Jetmonkey Guest

    thanks alot remy, that was really helpful. so i take it that once i had a preamp, like a tube for example that runs 1meg ohms, that would cover the mic (vocal) needs?

    and if you're still out there, or anyone else--i know this is tired--but any particluar semi-affordable model/brand suggestions?
     
  4. RemyRAD

    RemyRAD Well-Known Member

    Yes, the tube preamplifier's with direct instrument inputs on a 1/4" inputs are frequently quite high in impedance and totally appropriate for both balanced microphones and unbalanced passive electric guitar pickups.

    The one thing you must beware of is that some tube preamplifier's are not strictly tube preamplifier's but are hybrid units with both transistor/IC chip sections and a tube/tubes section. Sometimes those units use a transistor or IC chip input section that route to a tube output section and those may not have a high enough input impedance for a passive guitar pick up? You want a tube input. And if necessary a transistorized output? Not the other way around.

    I've got no real suggestions for any particular units as I don't personally own anything like that. Although I have heard some good things here at recording.org about the ART tube microphone preamplifier?

    And speaking of tubes, did anybody hear that one of the founding members of the TUBES died a while back?
    Ms. Remy Ann David
     
  5. Jetmonkey

    Jetmonkey Guest

    Thanks again!
     

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