Jeff Rowlands Amp and Dac vs. VAC amp and DAC

Rinpoche,
I'd play recordings that you both enjoy and are pretty familiar with. You're use to how they sound in your system and thus will easily detect any differences in presentation provided by a new component. This approach has been very effective for me through the years. We all here are interested to read your listening experiences with the select group of amplifiers.  This is an enjoyable thread. 
Charles, 

First thing I play when testing a system is album entitled 'Cielo e Terra' by Al Di Meola. It is atmospheric mesmerising acoustic guitar music.
Next I play vocal by Dead Can Dance. Then Bitches Brew by Miles Davis, then Inner Mounting Flame by Mahavishnu Orchestra, then the rest if I need to, usually not because by that point things are almost always clear to me. But if you listen to opera and big orchestra, it may make sense to start with that. Just don't expect too much - no system can adequately reproduce the power scale and instrument separation of a full orchestra. They can't record it adequately either, by the way.

I mentioned Purist Audio cables. They have a cult following, not that it is the only great brand. Cables can really make or break the system because signal transmission is just or almost just as important as signal processing. If you decide to buy them new, I suggest you contact albertporter here on audiogon. He is a very experienced audiophile with incredible system, he will help you choose the right cables, he sells them too. I talked to him in the past. Purist cables need at least 200 hours of burn-in time to sound best, I can confirm it.
I think, VAC has good Chinese tubes in it, but of course one can do better with New Old Stock tubes. Most people here replace those factory installed tubes, I guess. I would for sure.
Most agree that at their best tubes sound better than transistors but this level of performance costs a fortune. At more modest levels there is no clear answer, it depends on many things including personal preferences. You could even try " poor man's LAMM " Rogue Audio Pharaoh hybrid integrated. It's $3500 new, many like it a lot. Both VAC and Rowland integrateds are what, about $11000 each new?

Rinpoche,
I had to smile when you mentioned seeking inspiration from music to fuel/assist your writing process for your book.  I find music essential for both writing and mathematical calculations - - I just find it helps bring my mind to better focus (I'm a bit ADHD, so it is nice to have music exciting and activating some itchy brain circuit to steady me down).  And I find I can do both with great simultaneous involvement, truly having some ecstatic experiences in just such times.

I am a VAC Phi 200 owner that wrote about them a bit earlier.  I have heard that the iQ is a very nice step up in sound quality, so I think you are wise to wait for that audition before making a decision.  I will bet that it tips the scales!

I have changed from the stock VAC Shuguang tubes for sound that I find better:  Gold Lion KT88's for the power tubes and Shuguang Treasure CV181-Z tubes for the input and signal tubes.  And actually I have lately mixed the original Shuguang 6SN7 tubes back into the driver station for my favorite overall affect in my system and to my tastes.  My basic point is that there are better (different?) current production tubes to try, and mixing and matching can dial in the "flavor" a bit to suit.  And they don't break the bank, by any means.

Keep enjoying the journey, and I am sure you will end up with a musically satisfying system.  (And, yes, cables make a difference, too, but let's defer that topic for now...)

I hear you (no pun intended, LOL). At first I will probably be a bit nervous about tubes, but I am sure I will get the hang of it, if I go that route. I wonder, what cables do you use with the Phi 200? 

Also, I will listen to the musical suggestions. I am not familiar with them. I have eclectic musical tastes that include jazz, classical, rock, world music, and even ...
broadway!

One of my go to songs this time around for auditioning has been Peter, Paul and Mary's All My Trials. Just pulled it from the vaults and it is a lovely acoustic song. I have other tests as well including Bach's double violin concerto, Prokofiev violin concerto #2 Andante, Diana Krall's version of A Case of You, Maria Callas singing 'La Mamma Morta', Keith Jarrett (who by the way walked out of a concert I attended last year in Paris because too many people were coughing), and many, many more. So much great music. Now all I need is an AMP!!