I would be curious to know which of our products were 'modified' by Empirical Audio? The design of our tube circuits and topologies have evolved over time. I will admit that early ModWright tube mods that relied on a SRPP circuit had some HF limitations. I am speaking of mods that were performed 3-5 years ago. We have also improved and refined our power supply designs over time.
Dynamics can be a subjective term. I have heard designs that others considered to be very dynamic and detailed that to my ears were cold and sterile. I agree that bandwidth should be as good as possible and signal path purity maintained. I also believe lowering noise and distortion levels are also keys to improved performance and overall musicality. Power supply design IS key to any SS or tube circuit and a poor power supply design will compromise the circuit's performance.
As far as tubes vs. SS, I agree that both can exhibit similarly neutral sonic characteristics, if designed properly. I actually prefer system combinations of tubes for front end components and preamp, with SS amplification. This is my general preference, but does not mean that I haven't heard tube amps that I found to be extremely musical, engaging and accurate. The bottom line, IMHO, is that tubes amplify voltage best, while SS components 'amplify' current best. Front end components are largely responsible for amplifying voltage signal, as is the input stage of an amplifier. The 'power' portion of an amplifier is responsible for 'amplifying' current.
Ultimately, it is up to each individual to determine what sound they like best. It is true that different designers have their own house sound. Beyond objective measurements, there is a certain amount of subjective perception and appreciation. There is also the fact that the ear is a far more complex and sophisticated 'instrument' than any test gear that we as engineers have access to.
To sum up, if it sounds good (to you)...it is good ;).
Thanks,
Dan W.
President, ModWright Instruments.