A few months after starting it, I'm coming back to this thread to share a recent experience. In short: after experimenting with the Gold Lion KT-88's and Tung Sol KT-120's in my Prima Luna DiaLogue One, I ended up going full circle and back to where I started: the stock EL-34 tubes. These are labeled as "Prima Luna", but are actually made by Shuguang in China and, supposedly, only the better-rated ones end up being used for the Prima Luna amps.
My journey could basically be described like this: I started with EL-34's, loved the sweetness and midrange magic but needed a little more grip on the low-end, so I switched to Gold Lion KT-88's. The Prima Luna auto-bias feature took care of the rest. I LOVED that combination (and loved the way the Gold Lions LOOK, as inconsequential as that sounds), but reliability was an issue. One exploded while in use, and the rest would loose their sparkle and life in less than a year, with moderate to low use on the amp. At $200+ per quad for tubes that don't even last a year, things get expensive really quickly, so I needed an alternative.
I then tried the KT-120's that everybody was raving about, and I have already shared my comments and thoughts here on that front. Originally, they were not my cup of tea. Too aggressive and bright. I actually gave them a second chance, burned them in for at least 200 extra hours and they definitely got better (less harsh on the top, rounder in the mids, but with no extra "grip" gained on the bottom). Still, the magic was just not there and my amp was never designed with that tube in mind anyway, so why even bother?
I then went back to the stock EL-34's that I still had sitting in the closet. These were not as "sweet" and "magical" as I remembered them, ironically, offering bass aplenty (albeit looser, slightly sloppier bass, a quality that for some reason I tend to like on most material since it seems to allow the music to feel more tangible, less sterile and artificial), and an incredibly more open, extended and detailed soundstage, which definitely got "wider" and more stable when compared to the KT-120's. With the emphasis being on the mids, there's a lot of details to be gained that were perhaps a little obscured by the more linear characteristics of the KT-88's and KT-120's. Notes in the upper-lows are now considerably more clear and I'm simply hearing a ton more music in the bass and low end. Yes, the KT-120's were sturdier and maybe even allowed my Sonus Faber Toy Towers to go a little lower, but at the expense of detail and finesse, I believe. This translates into a significantly more "crystalline" presentation, with the well-known musicality and ripeness of the EL-34 in place, and one that I am finding myself preferring. It all works wonders with jazz and classical, particularly with strings, but rock albums actually sound more vibrant as well. Certain passages tend to break up a little bit, but oddly enough this only happens with very few instances of highly distorted guitars and/or very, very complex passages on extreme metal albums (a genre I also love). Overall, though, I think the EL-34's are back and staying, at least for now. Next experiment: the Gold Lion KT-77's. Anybody have any experience with them?
