Very simple, lots of "tube sound" buffer advice pls

Discussion in 'DIY' started by Ardacer, Jul 18, 2019.

  1. Ardacer

    Ardacer Friend

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    I'm thinking about making a tube effect "buffer", of a minimalistic design, that'd do a lot of tube sound. Not talking about clipping it into distorsion like for guitar amps, but also I don't want it to be as linear as possible. Something in between, with lots of tube warmth. It's possible to some degree to generate simmilar distorsions in software, but tube effects reach beyond simple "generate even order harmonics" linearly and better controlled clipping. There's some rather hard to measure distortion dependant on the source material, not talking imd, but something detectable in time domain. Would have to research again to find exactly what they meant, I forgot.

    So. I did some research, and have a general idea, but 0 experience with tubes. My idea was to take a double triode and bias it in the nonlinear part of the curve, and perhaps undervolt it too. Not sure that's the best approach.
     
  2. Baten

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    Some tubes also definitely inflict some phase fuckery which can be pleasing / have effects on sound stage :)
     
  3. Hrodulf

    Hrodulf Prohibited from acting as an MOT until year 2050

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  4. Ardacer

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    Thanks. I've read those already, but that's for designing linear low distortion gear. Not exactly what I had in mind.
     
  5. Tristan Jones

    Tristan Jones Acquaintance

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    You are a bit off base. You do not want to bias a tube into the knees of the curves. It will sound like utter crap regardless of your intent. (ask me how I know : P )

    Tube distortion is inherent to the tube and the way in which a tube amplifies a signal. More distortion can be incurred by running the tube outside of its ideal parameters, but that type of distortion does not always sound good.

    A good tube buffer will add in tube warmth but maintain (if not enhance) sound stage without adding in gobs of distortion.

    Now the one thing I probably wouldn't add is negative feedback or any sort of push pull topology. Either of those will tend to cancel out the tube harmonics and leave you with a less distorted, but an overly clean sound.

    I think if you made a really supper basic single ended buffer and kept distortion at a minimum, I think you would be VERY happy with the end results.

    Try JE labs 76 to 6sn7 preamp http://jelabsarch.blogspot.com/2012/06/je-labs-phono-and-line-preamp.html
     
  6. Ardacer

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    Thanks. That thing in the link is a phono preamp, so I'm guessing it's with riaa eq. I'll try to find/make some SET buffer then.
     
  7. sodacose

    sodacose MOT: WTFAmps

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    Worth noting that a buffer in the traditional sense is a cathode follower (or variation). These employ 100% negative feedback and as such normally remain pretty linear.

    A grounded cathode amplifier is more in keeping with what you're looking for but it will have gain. Low mu tube and a output transformer of comparable winding ratio might be a good solution. Similar to the output stage of a power amplifier.
     
  8. Tristan Jones

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    No no sorry. Scroll down on that page until you see the 76/6sn7 preamp/buffer. Ignore all the phonostage stuff.
     

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