Some Class AB amps will run in entirely Class A until they reach a certain high output level. At high output levels distortion from switching is very difficult to hear. They usually use a form of sliding bias. So you get the best of both worlds - low power consumption at idle and yet higher output of a Class AB design.
"switching" noises from SS Class-AB amps
Lately, I have been thinking that solid-state Class-AB amps can generate "switching" noises too. It has been known that Class-D amps generate switching noises, and noises reduction can improve Class-D amps. However, the output stage of a Class-AB amp also switches between on and off states.
Another example is the diodes used in the rectification circuits. It has been shown that using soft recovery diodes like FREDs can reduce the noises from the rectification circuits.
I am a big fan of Bybee purifiers. Some people, including myself, have used Bybee purifiers after the diodes or regulators with good results. Now, I am thinking to put Bybees between the output bipolar Collector legs and V++ or V--.
I have a hybrid power amp with tube gain stage and SS driver and output stages. I really like its bass and mid-range. However, its treble is not as "pure" as my KT88 amp. Additionally, I have a much more relaxed feeling after listening to the KT88 amp for hours. No stress at all!
Has anyone tried to reduce the noises from Class-AB output stage before?
Another example is the diodes used in the rectification circuits. It has been shown that using soft recovery diodes like FREDs can reduce the noises from the rectification circuits.
I am a big fan of Bybee purifiers. Some people, including myself, have used Bybee purifiers after the diodes or regulators with good results. Now, I am thinking to put Bybees between the output bipolar Collector legs and V++ or V--.
I have a hybrid power amp with tube gain stage and SS driver and output stages. I really like its bass and mid-range. However, its treble is not as "pure" as my KT88 amp. Additionally, I have a much more relaxed feeling after listening to the KT88 amp for hours. No stress at all!
Has anyone tried to reduce the noises from Class-AB output stage before?
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