Talk:Single-ended triode

Bias fixed or automatic
"Audio power triode is biased to Class A operation by applying negative bias voltage to its input grid (see diagram), or by raising cathode potential with fixed bias network."

I dont see any need for it to be fixed bias. Indeed automatic bias is more popular.

I've made a couple of small tweaks so the article represents SETs as a whole rather than one currently slightly fashionable corner of it. Tabby (talk) 12:09, 19 December 2007 (UTC)

There is an error in the schematic drawings. If a constant voltage is connected to the grid the way it has been shown in the drawings, then the voltage really is constant and no signal voltage may reach the grid to get amplified. The signal sees the constant voltage source as a zero impedance. Uikku (talk) 19:01, 6 May 2010 (UTC)

I agree with the error - it needs a resistor in series with the top side of the grid bias battery. Also, "automatic bias" is commonly called (at least in the USA) Cathode bias, as discussed in that article on it, which ought to have a schematic demonstrating it, as well as a link to it from this article. Benbradley (talk) 01:55, 28 May 2010 (UTC)

SETs introduce harmonics that were not in the original signal to a greater degree than other amps- "euphonious distortion"
This ought to be mentioned in the article. SETs have SIGNIFICANTLY higher levels of harmonic distortion than other designs, and many in the high-end audio community argure that they owe their "sound" not to purity but to the introduction of nice-sounding (bot not accurate) even-order harmonics.

Something of this controversy ought to be mentioned —Preceding unsigned comment added by 98.206.43.107 (talk) 10:46, 10 June 2008 (UTC)

Anode impedance
Plate or Anode resistance.

Plate resistance or "rp" is the word used in all textbooks over the last decates.In fact this is not correct. That would mean that; DC idle current flowing through the electron tube (valve) because of the fixed plate voltage. It is however the change in plate current, ensuing from a variation in the plate voltage, while keeping grid and cathode voltage constant. So the correct word should be "Plate impedance" or an amelioration for "plate impedance" should be "Anode Impedance"

March 7, 2009. Verelst Erwin —Preceding unsigned comment added by Verelst Erwin (talk • contribs) 16:35, 7 March 2009 (UTC)


 * This is DC electricity, there is no impedance in DC, what you may be thinking of is frequency change, which is not AC (AudioFOS). --John Bessa (talk) 00:50, 2 October 2011 (UTC)

Audio quality section
This is an example of a new concept that I have coined AudioFOS:


 * .. have achieved a cult status because of their excellent midband performance (argued to be the most important part of the audio spectrum in music reproduction)[citation needed], musicality, and directness. This perceived high sonic quality is mainly attributed to the simplicity and minimalistic approach of the circuits involved and the triode amplifying tubes that are typically used.

This is so far the purest of the verbal feces that I have encountered saturates tube amp descriptions: AudioFOS. Triodes don't amplify was well as tetrodes or pentodes because they don't have extra grids to combat the Miller effect, but it is these grids that add distortion in tube amps, and hence the desire for low output but clean triode amps.--John Bessa (talk) 00:47, 2 October 2011 (UTC)


 * That AudioFOS is a new word to me. Uikku (talk) 20:27, 3 October 2011 (UTC)

Estimating power output for a Class A1 amplifier from valve specifications
Encyclopedia sources don't usually give design instructions. Is this section needed here? — Preceding unsigned comment added by 71.171.16.106 (talk) 20:43, 24 December 2015 (UTC)

P[o] = P[ot] * (1 - Rp/Rl) is a bad estimate for output power, if we set Rp equal to Rl then we get P[ot] = 0, which is obvious wrong. — Preceding unsigned comment added by 88.84.61.128 (talk) 08:07, 2 September 2018 (UTC)