Big wattage amp guys: do you like soft clipping?

Discussion in 'Amps and Cabs' started by music321, Jan 29, 2015.

  1. music321

    music321 Member

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    There is another thread, the latest of many, dealing with low vs high wattage amps. By the way, those threads might be good in a "sticky". As part of this thread, IbanezRokr stated that he preferred large amps over small ones because, quote:

    Because it turns out I don't like power-amp distortion. I like a driven pre-amp, and a big clean power amp to make it louder. So 4 KT88's pushing 120 is what I fell in love with, I don't turn it up very loud, and I don't work the tubes hard. There's just current cruising through the power amp, nice and easy.

    To my understanding, the main differences between "solid state" and "valve" power amps are: output impedance, internal impedance, distortion, and soft clipping. Aside from the soft clipping, all of the others can be copped pretty well by a solid state power amp. Distortion is irrelevant, if power-amp distortion is to be avoided. This leaves soft clipping.

    So, do you like the compression/soft clipping provided by the power amp, or would you be happy without it? If happy without it, it seems an alternative to the heavy and expensive power amp might be something solid state.

    Edit: I remember reading elsewhere quite a while ago that this solution, irrespective of volume and soft clipping, was unacceptable. The poster claimed that this solution didn't "punch" through the mix very well. Why wouldn't it? It seems like "punching" through the mix would be a function of damping factor, which is a function of impedance issues (which are addressable in a solid state PA), and (I'm guessing) are experienced by the listener as a "sharply defined" sound rather than a "mushy" sound. So what gives?
     
    Last edited: Jan 29, 2015
  2. Longer

    Longer Member

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    I love a big clean guitar sound as a pedal platform, and have nothing against SS power as long as the amp sounds great when loud.
    The problem is that I haven't truly found an amp like that yet, and I'm unwilling to sacrifice my sound for conveniences.
    Very interested in trying the Milkman Half & Half though. Tube Pre, 300 watts, and 28.5 pounds. The steel guitar clips sound yummy.
     
  3. Longer

    Longer Member

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    Sorry man, didn't really answer your Q.
    If soft clipping is what, say, my Twin does when it's on 4, then yes, I love it.
    Loud, Crystal Clean, Tight & Bold.
     
  4. music321

    music321 Member

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    on 4? yeah, then you like it.
     
  5. stephen sawall

    stephen sawall Member

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    It's about girth for me. I have around twenty amps from 5 to 150 watts.... The big amps just have a bigger sound regardless of dB's. If everything else in the rig is identical.
    It really has nothing to do with clipping for me.
     
  6. nickcoumbe

    nickcoumbe Member

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    Hmmm, I had a peavey mace vt (ss preamp and 6x6l6 power section) so the opposite of what you propose. Hideously loud but when you go straight into the power amp in on the loop with a decent preamp it was pretty awesome.

    Impossible to play that thing past ten o clock unless you were playing in a stadium, so you never pushed the valves or got to the point of clipping.
     
  7. teemuk

    teemuk Member

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    You might want to plug that tube power amp to oscilloscope, overdrive it, and see how much it "soft clips" - if at all. You might get surprised.

    If power amp distortion is to be avoided then you don't want any kind of clipping: Clipping IS distortion. Soft clipping practically means earlier onset to distortion and greater amounts of distortion. Hard clipping means less distortion, until the signal unavoidably starts to clip. In practice, you won't be -hearing- much difference between the two.

    There is nothing trivial in making solid-state power amps soft clip too. All that distortion from the greater unlinear area of amplification, however, means you loose siginificant amounts of potential headroom to that more "gradual" distortion. It's practically a choice of efficiency vs. overdrive characteristics. ...Like it is with tube amps as well.
     
    Last edited: Feb 2, 2015
  8. riffmeister

    riffmeister Gold Supporting Member

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    Not sure about soft clipping, but I do like soft bath towels.
     
  9. music321

    music321 Member

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    So, if large amps with the volume down low aren't soft clipping, what would be the disadvantage of, or I should say difference between playing an identical tube pre into a solid state vs. tube power amp?

    I'm curious about this because if you can get the same performance out of a tube pre and solid state power section, as you would w/ tubes in both cases, you'll save money and weight.
     
  10. teemuk

    teemuk Member

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    Assuming the amps aren't clipping then it falls down to frequency response. Damping factor...? Overall bandwidth of the audio band...?

    If the amps are clipping, which they likely will be at some point, the tube amp will likely display more crossover distortion due to bias shifts and the clipping onset may be altered more by power supply sag. In some designs the screen circuit provides -slight- gain compression. Soft clipping is largely a myth, though it happens in some particular designs.

    But this is a topic that you really can't generalise too much. "Tube power amp" is a broad category. Tube power amp of a Vox AC30 is an entirely different animal than tube power amp of a McIntosh or Audio Research amp. Likewise solid-state power amp is a broad category. Peavey T-Dynamic power amp is nothing alike a "HiFi" power amp with linear response and abrupt knee to clipping distortion. Likewise, you can find significant differences from overdrive performances of various kinds of solid-state power amps.

    Don't believe the hype and broad generalisations. I rrecommend you research this topic yourself: Look for oscilloscope plots of overdriven tube power amps (real plots, not drawings), and in addition research various SS -guitar- power amp schemes, like T-Dynamics of Peavey, Valvereactor of Vox, MosValve amps of TubeWorks, Dynavalve design of Hughes&Kettner, the new patent of Quilter Labs, and various patents of Pritchard. It will change your way of thinking, guaranteed.
     
  11. music321

    music321 Member

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    thanks. I'll check it out.
     
  12. IbanezRokr

    IbanezRokr Member

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    Being the dude you quoted, I feel the need to add that my other amp I own and love, IS a hybrid with a SS power section, and I use it and love it for the same reason. Your argument completely has merit.
     
  13. gdomeier

    gdomeier Supporting Member

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    That's what I like about my full size Mark V vs my mini rec. I like to get the gain level I like at a sound volume I want (that changes day to day). I find it easier to get all amounts of gain at various volumes with the V vs the low watt mini.
     
  14. bigtone23

    bigtone23 Member

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    This. Girth. I also like not running an amp into redline as it requires the tubes and bias to be spot on or they will fail and take expensive components upstream out.
     

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