Interface FX send to amp?

Discussion in 'Converters / Interfaces' started by Koyaanisqatsi, Jan 4, 2011.

  1. Koyaanisqatsi

    Koyaanisqatsi Member

    Jul 16, 2010
    Hello, newby here...

    I use a Presonus Firestudio. I want to record a direct signal from an electric guitar, but also the live (tube)amp sound mic'd up. I don't have a DI or anything, so I've been trying stuff out. I like to record the raw clean sound, so i can always add a digital amp, or send it back to an amp, and re-record it with different settings.

    I've got it to work like this:
    Guitar>Firestudio>FX send>amp

    The amp got a signal, even before I opened the gain on the Firestudio. But the whole gain button didn't affect the sound at all over the amp. So I guess it's nothing to worry about.

    What I do worry about... Can the amp handle it? Is the signal from the send different from the raw guitar? And if so, will it hurt the amp? Or is there a different, better way to achieve this?

  2. Link555

    Link555 Well-Known Member

    Mar 31, 2007
    North Vancouver
    FX-sends should be a low-impedance output (100-300 ohms) at line level (Vpeak = 1.737), your amp is expecting a high impedance(20k to 50k) signal from your guitar (the typical guitar pick up puts out between 0.150 V peak to ~ 1.4 peak).

    Its best to use re-amp circuit to handle the impedances for you.
  3. Boswell

    Boswell Moderator Distinguished Member

    Apr 19, 2006
    Home Page:
    It's worth trying first taking the guitar output to both the amp and the FireStudio, as building or buying a re-amp box is a moderate commitment. The FireStudio instrument inputs on channels 1 and 2 are 1 MOhm impedance, so although you will get some tone change from the guitar pickup when feeding both the FireStudio and your amp, you can try it and see if it rules out the simple approach. Use a T-piece mono jack adaptor plugged into either the amp input or the FireStudio instrument input, and then a short jack-jack cable to the other piece of gear.

    Use a mic input to a separate channel on the FireStudio as usual for miking the amp. What type of mic do you have for this? What's your room acoustic like?

    The killer comes when you decide that you want to re-amp the recorded direct channel by feeding a FireStudio DAC output into your guitar amp and re-recording the output via a microphone. If this is what is in the back of your mind, you had better start building Link's nice-looking re-amp box sooner rather than later, as you can use it for the original recording via the FireStudio Send output rather than using a T-piece on the guitar signal.

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