High powered single end 300b recommendations

I'm using an Aric 300B set amp. My speakers are the Harbeth S-HL5+. I'm also using a pair of Rel T/9x subwoofers. My room is 12 x 19 and moderately treated. A Bricasti M3 feeds directly into the amp. My listening distance from the center of the speakers is 8'. I usually listen to Jazz and some basic rock from the 60's- 90's. The volume setting on the Bricastic is usually -20 to -25. This typically yields a volume of 70-80 decibels from my listening position. I have pushed the amp into the 90 decibel range on a rare occasion and not experienced any clipping. I live in Maine if you want to audition my system.

These are awsome but not cheap.

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one other consideration for you if you go to a Parallel or Push Pull 300b you will be replacing 4-8 300b's tubes when they go, worth it? they run what around $250 each these days for average ones. re-tubing gets costly fast. 

I had a home built BeePree 300B preamp and NAIM NAP100 power amplifier. That combination gave me the 300B sound and SS power to drive my Focal speakers. Not too expensive and very pleasant to listen to. Such a combination was mentioned earlier by Snowstorm above to use a 300B preamp and solid state power amp to get the best of both worlds.