Johnsonwu,
I respect your opinion without knowing how the 502 sounds with these mods. I expect they really will make an important difference.
However most of us are not equipped to do the mods ourselves or have access to electronic technicians who we know who will perform mods they don't use themselves or don't suggest recommend themselves. Controlling costs and assured quality by after market modification represents a challenge to the non DIYer.
Rolling tubes however is accessible and does have a meaningful impact on ultralinear amps, I am sure of this. The input tubes which are not in PP and almost allways have a meaningful impact on the sound. Indeed among many many rolling experiences, In every instance I was able to taylor the sound, except once. (An ARC preamp, which warned that tubes in certain positions, did not impact the sound. They were correct.) Again It is the only instance I have ever encountered in my years of tube rolling.
I respect your opinion without knowing how the 502 sounds with these mods. I expect they really will make an important difference.
However most of us are not equipped to do the mods ourselves or have access to electronic technicians who we know who will perform mods they don't use themselves or don't suggest recommend themselves. Controlling costs and assured quality by after market modification represents a challenge to the non DIYer.
Rolling tubes however is accessible and does have a meaningful impact on ultralinear amps, I am sure of this. The input tubes which are not in PP and almost allways have a meaningful impact on the sound. Indeed among many many rolling experiences, In every instance I was able to taylor the sound, except once. (An ARC preamp, which warned that tubes in certain positions, did not impact the sound. They were correct.) Again It is the only instance I have ever encountered in my years of tube rolling.