Can you tube gurus help me with something? I'm not sure if what I'm about to describe is valid, in my head, something I never noticed, accurate, or makes sense but in regards to the 5998 and 7236:
I was listening for a while last night to the 7308/5998 combo, and was trying specifically to identify the characteristics of the 5998's affect on the sound. I hadn't listened to anything for a few days, but I had left the amp on and playing music all day, so it was warmed up and ready to go. I put on a regular few selections of music I usually use for "test purposes", and these were my impressions of the 5998 in comparison to the 7236 (since I hadn't listened to anything for a while my sense memory was a clean slate, so I have no idea if these observations are correct).
I've always felt the 7236 delivered powerful and deep bass, with lots of impact. Off the bat, I was very pleased with the 5998 however. The bass seemed very ample, and my impression was that there was even MORE of it than the 7236 for the rock I was listening to at the time. There was a very palpable and solid feel to it, and something that I had not noticed before regarding the "sound" of bass...I was able to distinguish bass from guitars, drums, and bass clearly and seperately from each other, each had its own tone and flavor and location in the image, and had different "feels" to them. To clarify what I'm saying, I could tell the difference of individual bass notes, as opposed to an overall "bassy" feel...like, before, I could kind of "quantify" the bass and tell if it was clean and articulate, but this seemed to be more holographic. Overall, the bass was weighty and musical, very clean and detailed, and was less of a "boom bang bash" effect. The feel of the bass was very apparent, without muddiness or smearing.
My initial impression was that there was more bass than the 7236, with greater articulation. When I switched music to stuff that I always knew had more slammy bass (some techno and some rap stuff), my impressions changed. It seemed that although the 5998 presented a very articulate and distinct bass character, and hit every bit as deeply, it seemed that there was just "less" of it in terms of slam and impact. I could hear the notes I was expecting, they just didn't hit as hard. It was like listenting to a full size speaker rig with really nice full range speakers without a subwoofer. Still, I kind of preferred the sound overall to the more slammy sound I remembered. It was a very musical and toe tappy experience, and I could hear a lot more subtleties and nuances in the music that was getting drowned out by bass in the past.
The things I described about the 5998 and hearing distinct bass notes from different instruments may be present in other tubes that i have tried, I just never noticed it or thought to isten for it, so it may be just as present in the 7236. Since I hadn't heard the 7236 for a while, these observations of comparing the two are somewhat invalid, but I'm wondering if what I'm describing fits others' impression of these two tubes...