Tube-buffered FX Loops... What's the story?

Discussion in 'Amps and Cabs' started by Random Hero, Apr 8, 2015.

  1. Random Hero

    Random Hero Member

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    I've always used the buffer in my Timefactor, but am I right in thinking that in the loop of my Badger, which has a buffered loop, I won't need to? Won't the tone change when I switch the pedal on?

    What is everyone's experience with tube-buffered loops?
     
  2. fusionbear

    fusionbear exquirentibus veritatem Gold Supporting Member

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    Really depends on the circuit. There are many types that are very transparent.

    I am now using the series tube buffered loop recommended by Melin Blencowe in his book on tube preamps for guitar. Uses a 12AT7, very quiet, very transparent. Simpler than say a "Metro loss-less loop" which is a very high quality and desirable SS loop.
     
  3. Random Hero

    Random Hero Member

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    Interesting. Any other experiences?
     
  4. FFTT

    FFTT Member

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    Have it on my Bad Cat, never use it.

    The amp sounds so good by itself, I don't need no steenking pedals!
     
  5. guitarsngear

    guitarsngear Member

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    There are a few issues brought up in your question.

    1. Buffered FX loops - the point of the buffered loop is to bring the signal coming out of the preamp down to a manageable level for the pedals in the loop so that they aren't overloaded and distorted - also the buffer brings the single returning from the pedals and boosts it up in order to sufficiently drive the power amp. (there is also some impedance matching for your pedals in the buffer)

    2.Whether a buffered loop is tube or solid state doesn't really matter. A tube buffered FX loop is one that uses a tube for the buffer circuit as opposed to solid state components such as op-amps. The main reason for this is to maintain a 'pure tube' tone path - but your pedals will have solid state components so....yeah, but to some people having 'all tube' is really important. The tube buffer will also color your tone more, take up more space, generate more heat in your amp and create another component that needs replacing.

    3. Buffer pedals - having one buffer pedal or 10 doesn't change anything you are right, you only need one - but a buffer (stand alone pedal or built into another pedal) is meant to go as close to the guitar as possible. The point is to create a low impedance path from the guitar signal to the amp so that your high end doesn't get rolled off. Generally this is needed if you have a long distance from your guitar to the amp or have many pedals in front of the amp. Putting a buffered pedal in the FX loop will do nothing to help this problem. If you need a buffer pedal because of tone loss from long distance of cable, you want it to be the first, or as close to the first pedal in your chain as you can get - Guitar - buffer - other pedals - preamp - FX loop - poweramp
     
  6. Random Hero

    Random Hero Member

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    Thanks dude. Yeah I know about buffers before the preamp. I have a buffer there but I was referring to in the FX loop, largely because when I engage the Timefactor, the tone will change when it's on as opposed to off, right? When it's on, the buffer is active, when it's off, it'll be true bypass. I guess I'll just try it!
     
  7. buddastrat

    buddastrat Member

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    I just got that mini pedal and it's amazing. TC really has thought these things thru adding the ability to buffer, and pass thru dry signal as well as making pedals with good headroom which most companies don't address. Not to mention how good it sounds!

    To OP, I've needed to use buffers with pedals like Boss or MXR. That Suhr amp most likely will have a great loop, I think you're good to go.
     
  8. The Funk

    The Funk Member

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    The difference between a buffered effects loop and a buffer in the pedals in the effects loop is that you likely have 10 feet of cable between the amp and the effects which will introduce some loading. If none of the pedals in the loop are buffered there a lot of loading - all the circuitry plus all the cables for the round trip. This is coming after the preamp so you can't really make up for it.

    The buffer also matches the level and impedence to correctly match pedals. On the way back in, it brings the signal back to line level.

    I've had amps with solid state effects loops and tube effects loops. The tube ones worked better, but that might also be because they were in higher end amps where everything worked better. Both of my amps have tube driven effects loops. Also, sometimes the reverb circuit is run through the effects return tube for tube coloration in lieu of having a tube reverb circuit (which requires a transformer and an additional tube). My badcat does this and I know. Fuchs does this as well.
     

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