Wow, you have some serious work ahead of you. With the requirement of a truly balanced design and your focus on 3-dimensional qualities, extended and open top end, the field of products is truly small. I would like so much to hear the VAC as I suspect it is about the only thing to give the Callisto a run for the show without going to the next insane (Boulder) price point.
Please don't discount the Aesthetix Callisto because of your concern of the effort needed to get NOS tubes to sound its best. Even with stock Sovtek tubes, it still mightily outperformed the Calypso with premium tubes and the BAT by an equal margin. I followed Albert Porter's postings here on what tubes worked and my experiences when I tried the same were right on with his. His efforts and willingness to share saved me a ton of time and no doubt money as well. In a week's time you could locate all the tubes to replace the stock tubes and then not think about it.
JD (Jadem6 who owns the Calypso) and I both feel that the magic with the Callisto has got to be much to do with it's separate tube power supply. And we were both so focused on this that it took us a awhile to notice how superbly the Callisto renders and controls the bass that is so untypical of a tube preamp. The two chassis implementation can be a hassle, but then the VAC Renaissance is as well. The Calypso and thus the Janus would clearly not meet your needs here.
It will be interesting to hear the reports on your listening sessions and ultimately your feelings on the Ref3 as well.
John
Please don't discount the Aesthetix Callisto because of your concern of the effort needed to get NOS tubes to sound its best. Even with stock Sovtek tubes, it still mightily outperformed the Calypso with premium tubes and the BAT by an equal margin. I followed Albert Porter's postings here on what tubes worked and my experiences when I tried the same were right on with his. His efforts and willingness to share saved me a ton of time and no doubt money as well. In a week's time you could locate all the tubes to replace the stock tubes and then not think about it.
JD (Jadem6 who owns the Calypso) and I both feel that the magic with the Callisto has got to be much to do with it's separate tube power supply. And we were both so focused on this that it took us a awhile to notice how superbly the Callisto renders and controls the bass that is so untypical of a tube preamp. The two chassis implementation can be a hassle, but then the VAC Renaissance is as well. The Calypso and thus the Janus would clearly not meet your needs here.
It will be interesting to hear the reports on your listening sessions and ultimately your feelings on the Ref3 as well.
John