Here is a the summary of the TRP tube rolling session we did at my place with David, Fabio and myself mid summer this year. I think it should also be in this Thread.
Setup: We tested a variety of output tubes to see which ones are working best in the TRP. We kept the setup simple with the SuperKomputer feeding the TRP DAC. Amp was the Ayon Crossfire. Speakers the hORNS. So no pre-amp and no subwoofer was used.
The first round we did with the KR Ann Recti. Second round we compared our favorite tubes with the Takatsuki.
Music: Stevie Ray Vaughan - Tin Pal Alley (2.30 min. & 5:00 min.); Yosi Horikawa - Bubbles (from start 1-2 min); Jose Carrera - Misa Criolla (from start 1-2min); Keith Jarret - Köln Concert Part I (1-2 min from start & 6:00 min); Blues Company - Dark Day (1:30 min); Jon Hopkins - Abandon Window (start 1-2 min & 3:40 min)
KR / Tung Sol EL34: clear over full spectrum, well defined bass (one of the better we heard)
KR / Philips EL24 Blackburn Code (NOS): warmer than the Tung Sol, pronounced mid-range, lacks treble extension
KR / RFT EL 34 (NOS): most dynamic and defined of the EL 34, clean over the full specturm, more details, good flow, clearly the winner of the EL34s
KR / Brimar 6L6G (NOS): less dynamic than EL 34s, soundstage moves slightly further back, beautiful organic tonality, very smooth, less treble then the RFT but nothing to worry about, good bass quantity which is softer than with the EL 34s, most emotional and touching of the bunch
KR / TAD KT66: most bass quantity, missing snap, polished and glossed over, a clear pass from all of us
KR / Genalex KT 77 Gold Lion: massive soundstage, cleanest of the all, quite background, has the fullness of the EL 34s but is more precise adn more transparent, good treble extension, tonality is spot on, involving and physical, fantastic intradynamics, most complete tube of the bunch and in all disciplines ahead except from emotionality wher the Brimar is slightly better
Elextro Harmonix 6CA7 EH: a lot of details, most powerful, good punch and dynamics, missing body in the lower midrange/upper bass, does not transport the chest voice as the KT77 and the Brimar.
Our favorite tubes were the Genalex KT77 and the Brimar 6L6G. The Brimar is mor emotional but the KT77 more involving. Tonality of the Brimar is beautiful but not as correct as with the KT77. We switched the rectifier to the Takatsuki to find out how these two favoites would do with the Japanese rectifier.
Takatsuki / Brimar 6L6G: Depth, focus and imaging improved a lot. Also the soundstage increased. The Takatsuki completes the Brimar. Very detailed but never losing the flow and the focus on the complete picture. The step up from the KR to the Takatsuki is impressive.
Takatsuki / KT 77: Also here, the soundstage increases slightly. There's more air and better separation than with the KR. But the difference to the KR is much smaller than with the Brimar. We all could very well live with the KR.
Overall, the Takatsuki and KT77 was the winner of the day. If you own a TRP it makes sense to own a Brimar and the KT77 as they are quite different in their presentation. The KR is doing a great job overall. If you got the spare money, go for the Takatsuki”
Later Fabio tried NOS GEC KT66 and wrote the following:
“Did some further comparison between the GEC KT66 and Genalex KT77. After having had the KT66 in the system for several weeks I changed back to the KT77 and was first impressed by the presence, slam and details I got. The soundstage moves much closer to the listener. Dynamics and microdetails are great. At times I almost had a heartattack when an unexpected impulse hit my body. It reaches slightly deeper in the bass than the KT66. However, bass control is inferior to the KT66 with more focus on the very low end and a slight dip in the upper mid bass. The high gain, dynamics and details come at the cost of being less musical. Some music can sound a bit forced and nervous at times. The KT66 is more relaxed with lower noisefloor. Music just flows better. Details are presented in a more natural manner. Both tubes have excellent treble extension and reach deep down (the KT77 a bit deeper). Think of the GEC KT66 as a better version of the Brimar 6L6G.
If your system is a bit sleepy, you’re looking for more dynamics and punch or your pre-amp has a low input gain I would chose the KT77. If you want to calm down things and you are rather into long-term relaxed listening go for the KT66. Both tubes are exceptional in their own ways. I compared them in the TRP with the RK Ann. Rectifier.”