I have officially arrived at Planet Audio Utopia!
Like my previous "review" I can only offer meager elementary opinions, but here's what I can tell you thus far:
RCA Clear Tops vs. Sylvania JANs (approximately 60 hours of burn in on the CTs and over 120 hours on the JANs)
The CTs seemed to be a bit more tonally articulate (without any harshness) but I definitely feel that I lost a bit of fullness when compared to the sound the JANs provided me. This is especially true in regards to the bass and low end in general. The CTs (perhaps through this added articulation) added a hint of brightness to my HD800s but not to the point of being fatiguing. I agree with the opinions of fellow Head-Fiers in that the CTs would be a perfect match for darker cans. While a very slight improvement in soundstage may be evident, the shortcomings in how the bass is crafted force me to give the win to the JANs.
Mullard CV4003 (approximately 20 hours of burn in on the Mullards)
Now here's where I start to get happy. Although this may be considered a bit premature with only 20 hours on the Mullards, I can say that as of now, these are the tubes for me! It feels like I get the articulation, soundstage, dash of tube-e-ness warmth, and bass production I've been longing for with my cans. I believe the Mullards are a great marriage with the HD800s. At first, I thought the top end was being slightly shaved off, then I realized it was simply the bottom end being picked up a bit to provide a more complete output. All three families (bass, mids, and highs) just sing together in harmony with this latest roll in. While the JANs gave me the bass I was looking for, albeit mildly bloated, the Mullards give me that bass with a seemingly more authentic and truer presentation. It's as if the CV4003s understand how accurate the HD800s are and said "ok boys, we're good with that category, now let's go smooth out and polish off every other area and call it a day". A terrible analogy but describing what I'm hearing is hard to do with words. Now this of course is just my own opinion with my limited gear and expertise; however, I am so happy to report that I have found a set of tubes that give me everything I wanted when I purchased the 800s.
As more time gets put on the Mullards or when I roll in a set of Chinese tubes, I'll keep you guys posted. For anyone else that's thrown in some Mullards, I'd love to hear your feedback (especially if you're using HD800s like me).
Enjoy!
Lem
gear used: WA7 (with EH Gold Tubes) - WA7tp - WA7 USB DAC - HD800 Cans