What is a class G amp ?

"Call it improved class D"

Or is Class D improved Class G?

Class G has been around longer but never seemed to break out in home audio.

I suspect class D is more efficient. Also its no comparison soundwise between the Class G Hitachi receiver and current Class D Bel Canto ref1000ms I have heard. The Hitachi was not even close to being in the same league, though comparing a 30 year old 50 watt/ch (100 w/ch Class G) receiver with recent technology 500w/ch mono blocks is certainly not an apples/apples comparison.

maybe some others who have experienced both Class D and G can comment.

My gut feel is that Class G is a simpler technology for a Class A/B amp maker to implement for efficiency purposes than Class D, which a totally different beast from a design and technology perspective. Outside of that scenario, making a more efficient amp using more traditional amp technology, I suspect that Class D has the bigger upside in terms of its value for producing better sound quality in a smaller package that is also most energy efficient.

G has advantages in every area except sound quality; if that matters.

My understanding is that a Class G amp will distort differently than other amp designs, and that historically, distortion and with Class G how it exhibits itself in regards to sound quality (always near and dear to audiophile types)has been problematic. One would expect that newer Class G implementations would have a handle on that at least to the extent of providing competitive sound quality though I am pressed to see how Class G alone would result in better sound quality than Class A/B. Perhaps, this is possible at a particular price point, but not categorically?

I suspect Class D is a totally different beast in regards to sound quality and how it distorts compared to Class A/B/G amps so I am not sure a comparison is even warranted there.

The G stands for Freg G Sanford