Amp is 1M ohm, Boss buffer is 500K...into amp sounds better. Why?

Discussion in 'Effects, Pedals, Strings & Things' started by The Revolution, Apr 10, 2015.

  1. The Revolution

    The Revolution Member

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    Solution, modify the boss buffer to 1M ohm, so the guitar pickups are loaded as if you were plugged direct into the amp...anyone with me on this?
     
  2. The Revolution

    The Revolution Member

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    Pete Cornish setup Santana's rig with a 1ohm buffer for this reason, so the guitar is going to sound more like it is plugged directly into the amp...with so many modern pedals (Strymon etc) using 1Mohm buffers....did Boss get it all wrong?
     
  3. stinkfoot

    stinkfoot Member

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    1M input impedance would make the guitar slightly brighter, compared to 500K. But it shouldn't be a massive difference - I can't say that I hear a marked difference when there's a 470K tube screamer first in line, compared to a 1M Boss TR-2.

    Boss used 500K on the earlier designs simply because the bipolar transistors they used for the input buffer doesn't allow much higher input impedances. The later designs use a JFET at the input stage, which are much happier to operate at 1M.

    However, the notion that tube amps are always 1M, thus making them the ideal choice, is a bit of a stretch - there are plenty of amps with 500K input impedance too, and they seem to sound fine :)
     
  4. amz-fx

    amz-fx Supporting Member

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    There is more going on at the amp input (since it is a gain stage) than just the input impedance, and this makes the Cornish or Boss buffers sound different than the tube input - usually brighter.

    regards, Jack
     
  5. Jackie Treehorn

    Jackie Treehorn Member

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    Yes, and it's in parallel with your volume pot. Parallel resistor values (r1xr2)/r1+r2.

    Think of a Marshall vs a fender amp, both have standardised input and output impedances but sound quite different.

    One thing I think people on TGP maybe don't give proper consideration, is that often in electronics, there can be multiple reasons for an audible change.

    Impedance is not the reason, it's one of a multiple of reasons why that boss pedal changes the sound.
     

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