All this tube talk has got me to update my last year's league table, with newcomers xf4 tubes and SR Red fuses.
To give people an idea of how I rate these tube differences, I've used a simple subjective scoring system:
1 point = the smallest discernible change that I consider reliable, repeatable and desirable. Don't take this too literally, I haven't exhaustively cross compared every combination in minute detail. It's just a bit of fun to indicate my perception of the relative merits of each change. The scoring is based purely on SQ, irrespective of costs. Results:
- 0 Baseline for BHSE with stock JJ Mullard re-issue
- 2 Shuguang Treasure premium
- 6 Psvane EL34PH
- 7 Mesa Boogie STR-447, Blue grade (The rare White may be better if you can get them)
- 9 Vintage Mullard xf2 OO. Add or subtract 1 or 2 points depending on how you value the tonal sound signature
- 11 Vintage Holland xf4 DD (not the same as Mullard xf4 O)
Perspective time: Even the difference between 0 and 11 is probably objectively quite small - and unlikely to be noticed in meet conditions for example. It won't turn Diana Krall into Ella Fitzgerald, and it won't turn an SR-507 into an 009. OTOH, on a subjective music enjoyment level, once I've latched on to a 1 point improvement in the secluded bubble of my home, I don't like even a single point taken away again. YMMV a lot from this.
To relate the above scores to my other BHSE tweaks:
- The AMR fuses on AC input will add 1 point to any of the above combinations.
- The AMR fuses on power supply output will add 0 to 2 points depending on fuse direction!?! - see Note 1.
- The SR Red fuses will add 1-2 points on top of the AMR points, also affected by direction - see Note 1 and 2
- The Herbie Halo III dampers will add 1 to 2 points to any of the tubes, other than the Treasures, which were too big to try. Of all the above changes, I found the tube dampers the most difficult to quantify. Seem to sound best with a very loose fit - i.e. just enough to stop them from sliding down.
Note 1:
I know, I know, I KNOW! But I always tell it how I hear it. The Reds were also directional, even on AC input, which every Sound Scientist knows is impossible. But it costs nothing to try, and you can thank me later.
Note 2:
The advanced mathematicians would have worked out that the SR Red fuses can have a bigger impact than some tube differences. Yep, that's what I'm saying. Which is just as well, as I'm still smarting from just how much these little blighters cost compared to their apparent material content. About 4x the AMRs. Check the fuse thread for the safety warnings and different opinions.
In conclusion, my advice to the imminent new BHSE owners is still the same: Enjoy it as is. You may well find you need go no further. But if you do get that upgrade itch, then at least you'll know that it really can get better than this.