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Rant on the SET critics

Posted 8th March 2016 at 06:16 PM by DougL

I am so tired of hearing that anyone who listens to SET amplifiers "Must like distortion".

It must be comforting to be that simple.

The reality of the situation is a single ended tube amplifier is a very specific solution to a very specific problem.

The topology results in an implementation that has vanishingly low distortion at very low power levels.

This is a direct result of three factors,
Low distortion of the audio triodes used, the lack of multiple devices and the avoidance of the non-linear magnetic behavior around zero crossing.

FWIW, this only works in the tube world for very low power on very efficient speakers.

I still have memories of listening to a Klipsch horn with a Phase Linear 400. I could not stay in the room at any power level. It was near class B and arguably the worst amplifier ever made. Still, it took an efficient speaker to highlight its faults.

[End Rant]
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  1. Old Comment
    rjm's Avatar
    Low distortion of the audio triodes used, the lack of multiple devices and the avoidance of the non-linear magnetic behavior around zero crossing.
    If you wanna argue about how great SET amps sound you can argue all you want, but if the reasons you give don't make logical sense it's not an argument you are likely to win.

    Push-pull (transistor) amps operate in class A at low power. They have demonstrably lower distortion, and lower noise, than SET amps. "lack of multiple devices" and "non linear magnetic behavior around zero crossing" do not hold up to inspection. Parallelling devices give better performance, not worse (tube or transistor, push pull or single ended) and we've already determined that there is no zero crossing distortion in push-pull designs at low power as the output devices don't turn off.

    So you are left back where you started with "I like the way they sound." I don't disagree with that, but the assertion that "you like (the) distortion (specific to SET amps)" is still basically correct.
    Posted 9th March 2016 at 04:43 AM by rjm rjm is offline
  2. Old Comment

    I get it but....

    you can definitely make low power single ended amps to be ok or good...still have plenty of distoriton but can be ok

    IMO its not the amps but the darn speakers that are not good..(bandwidth limited)

    horns are well IMO have there own kinds of distortions/coloration's and your bound to these for (efficiency) reasons

    take your pick nothing is perfect mine is lower power SS and good wide band low distortion total system that sounds like music...

    Posted 9th March 2016 at 03:48 PM by Sk8Ter Sk8Ter is offline
  3. Old Comment
    I am not trying to "win" anything.

    I also don't care if you don't find my arguments compelling.
    I do not think AB push pull with feedback is appropriate for extremely low power situations.

    I believe it takes more than class AB to eliminate crossover distortion. Lets just agree to disagree.

    Its not even about the sound. Its more about posers sneering at engineering choices that are valid but don't fit into a their limited world view.
    Posted 9th March 2016 at 04:29 PM by DougL DougL is offline
  4. Old Comment
    Bas Horneman's Avatar
    I agree. The devil is in the details. Give me a pushpull ampflier any day of the week with <90dB speakers. Or even gainclones or what have you. But so far all pp amps don't stay in my main system with high efficiency speakers. The just don't perform...be it crossover distortion or whatever kind of distortion...they just suck. For my efficient speakers only SET will do....all else is unbearable.
    Posted 10th March 2016 at 11:41 AM by Bas Horneman Bas Horneman is offline
  5. Old Comment
    i like it
    Posted 12th March 2016 at 06:09 PM by sieras sieras is offline
  6. Old Comment
    abraxalito's Avatar
    Headphones are very efficient - about 100dB/mW. Since I've built a bal SE amp for mine, there's really no going back to classAB. All else is gaslight, so even though I've not heard a valve SET amp I understand where you're coming from.
    Posted 7th April 2016 at 02:35 AM by abraxalito abraxalito is offline

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