Decided to conduct some tube rolling with the Modwright Oppo BDP 95 to see if improved overall performance could be achieved. Here is a summary of the results.
1. After trying various 6SN7 tubes from varying vintages and makes, (at least a half dozen makes/types), the best overall performance was obtained with Sylvania MIL-SPEC chrome tops from the 50’s. They had more clarity, presence, and depth, along with a lower noise floor compared to other 6SN7’s I tried.
2. From there, tried 5692 tubes in place of 6SN7’s. All of the 5692’s were a step up from any of the 6SN7’s. Noise, clarity, dynamics, presence, you name it, the 5692 sounds and performs better, no question in my system. All the 5692’s sounded pretty similar (RCA, Sylvania, CBS). I think the differences are system dependant.
3. Once the driver tubes were settled upon, rolled in different rectifier tubes (5AR4, 5V4G, 5U4G) to see what differences there would be. I initially thought that there would not be much difference, but that was not the case. While all tubes worked well, the 5U4G tube provided the best overall performance with my setup. The 5U4G tubes had just a bit more clarity compared to the 5AR4/5V4G tubes. I also noted that the 5V4G tube seemed to have excellent clarity, but slightly (and I mean very slight) recessed presentation compared to the other tubes. The best over performance (lowest noise, best clarity, depth, presence) was the MIL SPEC 5931 tube.
It's interesting that although the power supply was designed for primarily the 5AR4, the 5U4G tubes I tried all seemed to be just a bit better match for the unit. The 5931 tube is absolutely a great tube, and provided an excellent match for the 5692 tubes with the Oppo.
PS: A thanks to my buddy for letting me borrow his stash of 6SN7's to audition.