I have been involved with audio since I was a kid. I had one of those magic uncles you only see in childrens' movies! But I am just getting used to tube amps, mostly because of access issues from India.
I have a Dark Voice 336SE. The original tubes were good, but I felt it could be better. I took advice from some seriously knowledgeable people on this forum and rolled the tubes. I couldn't afford the very pricey stuff. I changed the 6AS7 (bigger one in the back) with RCA, and 6SN7 (smaller one in the front) with Electro-Harmonic. Many Russian and East European tubes are being bought over and re-branded. It doesn't matter. As someone on this forum said, almost anything is better than the stock ones.
I am very glad I did change them, The sound is now full and lush (up from shrill and thin) with an improved sense of space and clarity.
Be advised that the characteristics of your headphones will dramatically alter your experience. A can like V-Moda is naturally meatier and bassier than many "neutral" ones. The DV can sound unbearably boomy and bloated with this can. It is best used with a really precise solid state rig.
Beyerdtyamic DT990 needed getting used to. It is very, very neutral and uncoloured. Playing off the DV, I thought it sounded thin. Rolling the tubes made a big difference. Even so, it is so much leaner than other less neutral, closed headphones. Once you've got past this initial impression, you will begin to appreciate both the DV and the DT990 for the amazing level of detail and trueness you can hear. It adds next to nothing extra to the sound.
Cans like Audiotechnica M50X and AKG K550Pro, both very much main stream items, will probably give you the experience you're looking for. These cans are not considered strictly audiophile by the permanent residents of audio heaven, but they are immensely popular and very well received by critics and reviewers alike. They produce a less than completely neutral sound, but the colouring is nowhere as pronounced as it is with the V-Modas or other Richter scale 8 headphones. The mids have great presence, the highs are crisp without hissing at you. The bass will make you nod with the beat, and the top of your head can stay there. Overall, the sound is "warm" as you would expect from a tube amp, with enough detail to keep you happy.
PS: if you can, do invest in a decent power conditioner. It will iron out the wrinkles present in the domestic electric supply to the DV, protecting it, and improving sound quality a great deal.
Enjoy.
