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line outs into mic ins

Discussion in 'Recording' started by unguitar, Oct 30, 2005.

  1. unguitar

    unguitar Active Member

    I would like to send the line out coming from my switchblade ( line mixer-splitter) into the inputs of an old and nice Tl audio indigo mic preamp.
    It happens that I am overloading its inputs ( using a jack to xlr cable).
    Is there any simple solution to keep my levels and feed it with a lower signal ( I mean: any particular cable solutions) ?
  2. johnthemiracle

    johnthemiracle Active Member

    not a cable solution but you could use a di box. these boxes are usually phantom powered and have a pad switch that allows you to adjust the levels correctly. at least that's what comes to mind off the top of my head...
  3. moonbaby

    moonbaby Mmmmmm Well-Known Member

    I am compelled to ask why do you want to run the output of a line-level mixer into a mic pre? Doesn't the TLA have a line (or at least "instrument") level input on it that allows you to connect it to other sources?
    The suggestion that you run the signal through a DI box wasn't thought through well. They generally take a fairly weak, unbalanced signal (electric bass or guitar) and "balance" the signal so that it can drive long cable runs. Some do this with a passive transformer, others do it with active electronics powered by phantom power. These are not attenuators! You MIGHT get by with a passive-type of box running it "backwards", but the levels and the loads will still not be correct. All you will get is about a 20dB drop in the signal strength. Taking the +4dBm line level of the mixer to a -50dBm (nominal) sensitivity mic input on the TLA will require substantially more attenuation.
    I believe that to do what you are attempting to do somebody will have to build you a special "attenuator cable" that will have a small resistor-based "H-pad" circuit in it and then terminate it with the proper connectors. You might try contact a local tech at a radio/TV staion or studio to see what they can do for you. I have had pretty good results having a broadcast tech fabricate "custom" things like that...
    Note that there are commercial boxes on the market that will take a strong +4dBm signal down to "consumer grade level" (-10dBm), and you might be able to trim that back some, but still....
  4. 43hertz

    43hertz Guest

    This is definitely not correct. John is correct that you need to use a decent DI box. There might be some unknown model that
    will not attenuate but I've never seen it. Google "Countryman Type 85" and you'll see the built in pad. I own several cheaper ones that will even take a speaker level signal(up to 300 watts! :shock: ) and knock it back to a nice clean, balanced, mic-level signal.
  5. moonbaby

    moonbaby Mmmmmm Well-Known Member

    I thought that the Switchblade was a balanced line level output...now they offer models that are not. I made an erroneous assumption that these were BALANCED outs on it...my mistake.
    I have a pair of the Countryman DI's.They have not behaved very well with a balanced source plugged into them.
    I still think that the DI route for this is not the most practical or cost-effective. A good DI (like the Countryman or a Radial) will easily set you back $175.00/channel. And cheap DIs sound....cheap.
  6. unguitar

    unguitar Active Member

    The Switchblade HAS balanced outs ( actually it is all balanced).
    The Tl Audio I am talking about is the Indigo series model 2001, which has just mic ins.
    I was thinking to some "things" in the cables ( I really know nothing about electrics beside the very basic things) as I wouldn't like to add anything in the signal path.

    The reason I'd like to do this connection is because I was looking to get some different "colours" from my dry sound and the Tl Audio is the only preamp I have that has no line ins.

    Thanks you a lot for your replies !

    Oh !
    I forgot to tell you that I don't use guitar preamps, I always record and play live going direct.

    Thanks again,
  7. moonbaby

    moonbaby Mmmmmm Well-Known Member

    If you are using balanced connections and want to keep it that way going to the TLA pre, a cable with the appropriate "H-Pad" (a network of 5 resistors) inserted is the way to go. Shure also offers a balanced attenuator (built into a small metal tube like their adapters), model#A15AS. It will provide you with a switchable pad that will go to -25dB. These are transparent to the audio fidelity, and the 25 db attenuation should be (barely) enough to get things under control. A pair of these (in case you are doing stereo out of the Switchblade) will set you back less than $100.00 (U.S.). IMHO, this is a more practical solution than sticking a DI in the path. And very few DIs are designed to be "flat". As good as the Countryman is, it is designed to "see" an unbalanced source at its' input. You want to keep as much of your signal flow balanced, especially in less-than-ideal environments where RFI and other gremlins can rear their ugly heads! PEACE!
  8. unguitar

    unguitar Active Member

    I found it !
    thanks, that is what I was looking for.

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