For warmer sounding amps (something that would complement the Turnberry), I would look for amps run will 6L6 or KT66 tubes. I would tend to avoid KT88 amps because the tendency to have a "hard" or "brittle" sound might exaggerate the slight tendency toward sibilance of the Turnberry. Of course a 300B pushpull or single-ended amp will have the right tonal qualities, but, the issue would be sufficient power. I personally don’t listen at very high volumes so my compromises would be in favor of low-powered alternatives, but, this is a personal decision.
These days, not that many amps are made with KT66 or 6L6 tubes because they have a lower output than other similar tubes making it harder to sell in a market driven by output specification. But, to me, they are the best sounding tubes of tetrode/pentode types. I also like EL84 amps, which are often the tube of choice in lower cost amps, but can still deliver lievly and punchy sound without being thin tonally.
This is a very good point. The Tannoy horn tweeters can get a bit sharp up top, especially on some vintage pop / rock vinyl. The KT66 / 6L6GC has a sweet sound that is a good complement, but the current hifi amp market largely ignores these tube types. I often use KT88 / KT120 amps on my Tannoys, but sometimes wish for something a tad sweeter.
I wish it were more common to see really nice modern amps (auto-bias circuitry, large transformers, premium parts, no 12AU7’s) made with MULTIPLE push pull pairs of EL34/KT66/6L6GC to hit say ~ 100 Watts.
My experience with EL34/KT66/6L6GC is years ago on Kensington SE (93dB). I had a few vintage amps restored, which used these tubes. Good for 20 - 35 Watts per side. Really sweet sound, but at the end of the day that's not quite enough power for me. I listen loud. Sure 8 Watts can get loud on SOME material, but the dynamics will be softened/compressed and you'll start to hit hard clipping on more dynamic recordings.