Comparison of a class D 2x50W to a class A 1x100mW music power amplifiers

Guess which sounded better.


The class D is a typical home theater amp from a well known maker.


The class A is just a 2N3055 power transistor and a 10KΩ biasing resistor as described on a nearby euroelectron post.


The class D no matter how loud, it sounded small and distorted.


The class A no matter how soft it sounded loud and musical.


The SPL of the class D was of course higher when the volume was increased but at least the class A was playing music.


The class A sounded more dynamic with impact on bass and drums even at very small SPLs.


There was distortion on both amps if the ear was close to the loudspeaker but this might have been from the CD also.


At least the distortion from the class A amp sounded more musical.


Signal path, setup:


CD Ingenue - K.D. Lang - Constant Craving - Sony CD Walkman D-EJ758CK - power amp, class D or Pleiades 2N3055 class A - Sony APM-078


Is this why 1 or 2 watts of a single ended class A electron tube amplifier send to the cleaners anything else? Perhaps it is time to build a single ended EF183 Pleiades amp with batteries, search on google for the relevant euroelectron post. All safety precautions must be taken into account, left hand always in back pocket etc.


And Is this possibly the reason why the "state" "of" "the" "art" class D amp now goes on eBay for 50usd (everybody seems to want to get rid of)? whereas a 2x2W electron tube single ended class A power amp from the same company made 50 years ago goes on eBay for 250usd. Consumers are clever. They listen to it at their friend's, their jaw drops and then they search and bid on eBay.


Class A amps have the least distortion at small levels on the planet and gradual distortion at higher levels, like nature itself. When using mathematics we take the first term of Taylor's series for small signal levels. Nature is assumed to be linear at small signal levels or small excursions.


Class A means electrons flowing all the time.


It is important to re,ever what the Hollywood engineers in the 30s discovered. That the game production-reproduction is not correct by judging from microphone to loudspeaker. But from the brain of the artist to the brain of the listener.


References:


Tubes vs Transistors, Is there an audible difference - Russel O. Hamm - JAES


Applied Electronics - T.S. Gray - MIT


http://euroelectron.blogspot.gr/2017/11/a-simple-2x500mw-pleiades-power.html


Basic Electronics - US Navy (NAVPERS) - Dover


(Flat frequency responce from vocal chords of actor, singer's vocal chords to listener's brain), Sound Picture Recording and Reproducing Characteristics - Loye, Morgan - Journak of the Motion Picture Engineers