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Mic pre-amps

Discussion in 'Vocals' started by AUD10, Nov 9, 2008.

  1. AUD10

    AUD10 Active Member

    What is the advantage of using expensive microphone pre-amps if ultimately, the output is going to go through the pre-amp circuitry of a mixer channel anyway?

    Thanks :?
  2. TopherNeverDies

    TopherNeverDies Active Member

    It wouldn't. I don't know the exact outcome of putting something thru 2 preamps but I imagine an explosion of some sort? Well maybe not that bad.
    Anyhow you wouldn't have signal flow like that. On good consoles you have patch bays, which when directing the signal into a fantastic piece of outboard gear would bypass the mic-pre. I. E. you take the signal from before the pre and return it after the pre.

    Now on a digi003 there are options for your input source. Like +4dBu or
    -10dBv or mic input. So I wouldn't plug my LA-610 into the digi003 as a mic input. Hopefully someone who knows more can better explain this but do you see what I mean?

  3. That's what patch bays are for. You can patch it into the signal chain to the fader in section, or anywhere else offering a patch point on your mixer.
  4. Boswell

    Boswell Moderator Distinguished Member

    This has nothing to do with patch bays. An external pre-amp should replace the pre-amp in the signal flow through the mixer or interface so the signal does not go through the original pre-amp.

    It means that, to be of any use, the interface or mixer has to have line-level inputs that directly feed into the ADC or the mixing circuitry after the pre-amp and are not simply attenuated and fed into the microphone inputs.

    Sometimes insert returns can be used for this purpose (which is maybe where the patchbay red herring came from), but often inserts are unbalanced and so require care if they are to be fed from the balanced outputs of external pre-amps.

    Is this question posed out of passing interest, or do you have a specific requirement using existing pieces of equipment?
  5. AudioGeezer

    AudioGeezer Active Member

    The first goal is to change mic level into line level. The line level signal is usually feed to the recording device. The recorder usually wants to see line level at it's input. The nice way this goal is achieved usually means spending about $200-$1500 per channel.

    Use what you have. Spend what you can afford. In this case more $ usually means significantly more fun.
  6. AUD10

    AUD10 Active Member

    No, it's just a question that came to my mind when reading through some of the threads on this forum!

  7. My question about this.. For example you have a preamp you want to use with your mbox2. Now what do I do with my output from the outboard pre? Into the xlr input on the mbox, or the line/instrument or DI?
  8. TopherNeverDies

    TopherNeverDies Active Member

    Got the manual? I don't have a mbox but I'll take a guess. I imagine there's a quarter inch input for line level? I plug in my LA-610 mkII into input 5 on my 003 rack. I can't go XLR to XLR because the XLR input is only for the mic input. So it goes XLR out of the preamp and quarter inch trs into input 5. On the 003 I have the option to set that input to -10dBv or +4dBu. I assume this would be the same on the mbox but you would want to look into it.

  9. Boswell

    Boswell Moderator Distinguished Member

    The only meaningful place to send the output is into the TRS line input of the Mbox2. However, the Mbox2 has less than stellar analog performance and you could be compromising the audio quality of your external pre-amps by routing them through the Mbox2.

    Do you actually have an external pre-amp or are you just considering getting one? If you haven't got one yet, think about ones that have a built-in ADC with S/PDIF outputs as well as the normal analog outs. You can then route the S/PDIF digital signal into the Mbox2 S/PDIF inputs and into PT that way without signal degradation.
  10. I was considering getting one because i'm not a fan of the mbox2 pres, and i have a AT4040 on the way. I was looking into joemeek, ART tube MPA digital maybe? and a bbe

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