yep i have the answer to your question x1000 i knew George and probably owned more GW stuff then anyone on earth including the WPA22 which only 2 were made before he passed as the third was on the workbench when he died...and the reason why he chose the tubes he chose in ALL of his products was because there was probably NO ONE in the world that had more knowledge of tubes and their capabilities then GEORGE WRIGHT....he started in single digits hanging around one the the most knowledgeable TUBE guys in history...there ya have it