Grant,
I'm not so sure yet that the issue is with the amp interaction. It might be just a coincidence that we both share sister amps. I am going to take an educated guess that based on my experience(with changing out the output caps, experimenting with different brands and values, as well as with many smaller bypass caps)that there might be a phase anamoly or irregularity with the new output caps and the solen bypass caps. In the TP 2.0 version with upgraded Hovland caps, rated at 4.7uf, I tried different values of the same Hovland cap( 1uf,2uf,3.3uf, and 4uf) None sounded as good as the 4.7uf value which Joseph was using. This lead me to believe that Joseph knew what he was doing and had pretty good ears. I later tried various Audiophile-type caps( Dynamicaps,V-caps) with same and different values and always came back to the 4.7uf value. For some reason, this value worked best with my VAC amps and sounded the best to me. Initially, I preferred the V-caps( 4.7uf oil-impregnated) because they just had more life and dynamics to them. But after a while there was this over-warmth and smoothing effect which robbed the music of proper attack to my ears, so I eventually went back to my trusty Hovland caps. It was when I recently found a new power cord line, Fusion Audio) that these really brought out the life and realism of my system, especially the TP 2.0. Everything finally just "clicked" in. Based on my faith of Joseph's ears and work, I decided to try the new upgraded version and that is where I am now after about 130 hours of burn in. One of the things that I noticed when I was experimenting with different caps and bypasses, the preamp never, and I mean never, sounded right with the bypass caps, no matter what value. Every bypass cap caused some type of phase anamoly which skewed the frequency response in an unnatural way. Depending on the value of the bypass, this skewing ,or plateau-effect, if you will, took away that natural balance and breath of life from the music. My TP 2.0 sounded its best when only one value cap alone was used in the outputs. Ultimately, as imperfect as the Hovland 4.7uf is, it sounded the best in the circuit of the TP 2.0. Joseph got it right the first time around, IMHO.
I'm not so sure yet that the issue is with the amp interaction. It might be just a coincidence that we both share sister amps. I am going to take an educated guess that based on my experience(with changing out the output caps, experimenting with different brands and values, as well as with many smaller bypass caps)that there might be a phase anamoly or irregularity with the new output caps and the solen bypass caps. In the TP 2.0 version with upgraded Hovland caps, rated at 4.7uf, I tried different values of the same Hovland cap( 1uf,2uf,3.3uf, and 4uf) None sounded as good as the 4.7uf value which Joseph was using. This lead me to believe that Joseph knew what he was doing and had pretty good ears. I later tried various Audiophile-type caps( Dynamicaps,V-caps) with same and different values and always came back to the 4.7uf value. For some reason, this value worked best with my VAC amps and sounded the best to me. Initially, I preferred the V-caps( 4.7uf oil-impregnated) because they just had more life and dynamics to them. But after a while there was this over-warmth and smoothing effect which robbed the music of proper attack to my ears, so I eventually went back to my trusty Hovland caps. It was when I recently found a new power cord line, Fusion Audio) that these really brought out the life and realism of my system, especially the TP 2.0. Everything finally just "clicked" in. Based on my faith of Joseph's ears and work, I decided to try the new upgraded version and that is where I am now after about 130 hours of burn in. One of the things that I noticed when I was experimenting with different caps and bypasses, the preamp never, and I mean never, sounded right with the bypass caps, no matter what value. Every bypass cap caused some type of phase anamoly which skewed the frequency response in an unnatural way. Depending on the value of the bypass, this skewing ,or plateau-effect, if you will, took away that natural balance and breath of life from the music. My TP 2.0 sounded its best when only one value cap alone was used in the outputs. Ultimately, as imperfect as the Hovland 4.7uf is, it sounded the best in the circuit of the TP 2.0. Joseph got it right the first time around, IMHO.