Using guitar FX within a mix

Discussion in 'Guitars' started by Jaike, Jul 9, 2009.

  1. Jaike

    Jaike Active Member

    Sep 15, 2005

    Is there an easy way to solve the impedance problem you face if wanting to put parts of your mix through guitar stomp boxes? Is it OK to just use balanced -> unbalanced cables, or is there more to it than that?
  2. Davedog

    Davedog Distinguished Member

    Dec 10, 2001
    Pacific NW
    It depends where you bus the stomp boxes from and where you bus them to. Using the inserts of a channel will get results, but more than likely will result in some added noise depending on the quality of the box.

    This is where you'll know about the gain of your box and whether it is true bypass.

    The input gain on a stompbox is usually intended for a guitar output which isnt much in comparison to a rack device of some sort.

    I will always put a DI in front of the stompbox to achieve this, and use the inserts on the channel I want effected.

    You can achieve some very interesting sounds this way, but degrading the signal makes it difficult to use them in a mix.

    Try the DI in front and see what you get.
  3. MadTiger3000

    MadTiger3000 Active Member

    Nov 16, 2004
    I've done it using the effects send/return system of a mixer before. Used some cheap multi-effect box.

    The DI into the insert is a nice idea, though.
  4. RemyRAD

    RemyRAD Member

    Sep 26, 2005
    Here is my take on using the tire stop boxes in a "re-amp" situation.

    Your first problem is that of gain matching. The guitar typically puts out a very low gain signal. That's what the stomp box wants to see at its input. It doesn't want to see + 4 DB. That's just way too much. So while Dave indicates the use of a DI box, a transformer, not active, DI box, we'll be, in a sense running it backwards. So instead of boosting the gain by 10 or more DB, running it backwards will achieve the opposite. You'll be reducing the gain by 10 or more DB. This is not possible with an active DI box as those are strictly heterosexual. Transformer coupled DI boxes are bisexual in that they can be used in either direction. Of course, you'll still need some adapter cables to make this work properly. After all, you're stomp boxes don't have XLR inputs. In this situation, you absolutely DON'T want a standard transformer couple DI box again. You merely need a passive XLR to 1/4" mono/unbalanced connector. Some stomp boxes even have their own internal pad switch. But beware of those as those can load down the wrong signal. You don't want to short your output by more than 600 ohms. You can do that to the input but not the output.

    If any other hand your output's are that of most consumer output levels then, they may in fact already be -10 DB outputs. Most likely a stomp box can accommodate that level. So you may need no transformer coupled DI box would merely an adapter cord without any transformers. We all gone to this and so you must experiment to find your best compromise trade-offs. It's either going to be too much level or too much noise. This is where stepping up or stepping down levels can help. Anything over a 20 DB window either way, will make it sound good or make it sound bad. 20 DB is not hard to deal with.

    Revamping my reamping
    Ms. Remy Ann David
  5. Boswell

    Boswell Moderator Distinguished Member

    Apr 19, 2006
    Home Page:
    Remy's pretty much on the nail here, even though I've yet to come across a stomp box that has the dynamic range and noise and hum levels that I would want to put any of my mixes through.

    The OP indicates that he wants to put parts of his mix though the box, so by this I take it that individual channel inserts are not what is needed, and that the source will instead be an aux or bus out of a mixer, or maybe even a sub-mix via a DAC from a DAW.

    There are three things to note about the input of a stomp box: (a) it's unbalanced, (b) the maximum input signal level is going to be of the order of -20dBu, and (c) it does not care about its source impedance. Taking these things into account, the way to drive a stomp box from a mixer's balanced aux output or equivalent is via an unbalanced attenuator. Noting that taking an unbalanced feed from a true balanced output gives you an inherent 6dB signal loss, you are going to need something like a 20dB external pad. If it's an unbalanced or only an impedance-balanced output, you get the full whack of signal on the +ve output, so a 25dB or 30dB attenuator may be needed.

    The unbalanced output of the stomp box is quite OK for routing back to an instrument input on an interface or on a mixer, or via a DI box (active or passive) into a mic input.

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