Splitting a signal - possible impedance issue?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by mike80, Mar 26, 2008.

  1. mike80

    mike80 Member

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    I just bought a Digitech GSP2101, and I'm looking to hook it up to my Mesa. A problem I ran into is that I want to use the analog section for EQ'ing my clean tone, but don't want any EQ'ing on my Mesa's distortion. By reading the manual, I figured out how I can do this by running a Y-cable to both the GSP and the Mesa, using both preamps for clean and summing the outputs, but use only the effects loop for the digital section of the GSP for effects on distortion.

    My question is - Will this cause some sort of impedance problem or significant signal loss? I won't be around my gear to test it out until later this weekend, so if anyone has some advice, it would be greatly appriciated.
     
  2. mike80

    mike80 Member

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    Gee, that's awesome.
     
  3. donnyjaguar

    donnyjaguar Member

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    Clearly you're in uncharted territory.
     
  4. mbratch

    mbratch Member

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    Mike -- could you be more specific about what cable is being run where? There are various GSP / Amp configurations that can be considered, with various connections through FX loops. Does your Mesa have an FX loop?

    If you could state the connections specifically from guitar through to power amp of the Mesa, then that will help.
     
  5. mike80

    mike80 Member

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    Basically, what I got from the manual is to run the guitar cable into a y-splitter close to the units (My Mesa and the GSP will be in a road case), then one Y will go into the GSP's front input, and the other Y into the Mesa's input.

    From the Mesa's FX loop send, run into the GSP's FX loop return, then run from the GSP's output into the Mesa's FX return. I would have the GSP's FX loop set to Summed on the clean programs, and No Sum for the distortions...that way I can use the analog preamp on the GSP for clean EQing and effects, and the Mesa's distortion would just use the digital processing of the GSP (for delays and such) and not use the EQ. Everything will be controlled via a Behringer FCB1010 midiboard.

    So since I'm wanting to split the guitar signal to two units, will that cause some sort of impedance issue within the inputs? Will I need a buffer of some sort to counteract any signal loss? I'm not sure how the inputs will react. I'm thinking there will probably be a ground loop issue which I will take care of at a later point.

    Would it be better to just use the GSP for it's digital processing, and insert a digital parametric EQ algorithm for the cleans? E.G: Plug straight into the Mesa's input, from Mesa's FX send to GSP's FX return, GSP's output into the Mesa's FX return - not use the input on the GSP?
     
  6. mbratch

    mbratch Member

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    Generally this will not cause any impedance "problem" as long as you're using musical instrument cables throughout (not speaker cables). You can try it out certainly without harming anything and it should sound decent. Whether the splitting of the signal causes enough loss for you to detect a sound degradation will be up to your own ears, and that will dictate whether you require any additional buffering. But from a technical standpoint, additional buffering is not required.
     
  7. mike80

    mike80 Member

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    Thanks much.

    I'll get to try it out tomorrow.
     

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