https://guitarnoise.forum/live-sound/classes-and-biasing/ Guitar Noise Discussion Board en-US Fri, 05 Jun 2026 00:18:07 +0000 wpForo 60 https://guitarnoise.forum/live-sound/classes-and-biasing/#post-69317 Tue, 14 Sep 2004 10:12:33 +0000
There is a lot of hype about Class A amps. Many amps advertised as Class A are really AB.

Class A amps]]> Live Sound Wes Inman https://guitarnoise.forum/live-sound/classes-and-biasing/#post-69317 https://guitarnoise.forum/live-sound/classes-and-biasing/#post-69181 Mon, 13 Sep 2004 08:43:49 +0000
There are amps designed that can be run both ways. Most Guitar amplifiers that call themselves "Class A" are really just Cathode-Bias Class AB Push-Pull circuits.

If its a new amp you shouldn't have to put new tube in it, unless you change to a tube that is a non-factory installed value or brand, something has happened to the tubes that are in it or something is wrong inside the amp. Generally if you get a set of matched tubes (duet or quad) and install them. However checking the bias when installing tubes is really the way to go and then after a month when the tubes get broke in check and adjust again. You should re-bias the amp whenever you change power tubes or modify the power amp circuits.

Hope this Helps

Joe]]> Live Sound forrok_star https://guitarnoise.forum/live-sound/classes-and-biasing/#post-69181 https://guitarnoise.forum/live-sound/classes-and-biasing/#post-3737 Mon, 13 Sep 2004 00:53:36 +0000 Live Sound alexk https://guitarnoise.forum/live-sound/classes-and-biasing/#post-3737