Additional thoughts on this.
First, the Apollo 11 have been a great amplifier evaluation tool. Real chameleons. Exceptional HF extension and phase. Coherent mids. Decent low end dynamics, but not quite pipe organ territory. An easy load and not too sensitive to damping factor.
The LM 845 Premium is an enjoyable amp and certainly a great value. My wife liked it best and looked at me cross-eyed when I sold it, LOL. I upgraded the driver tubes and ran it as an amp from my Allnic L9000 preamp. The front end at that time was an Antipodes K50 server into a Lampizator Pacific dac. Very capable. It’s a lower mid centric in presentation, and I liked that. Upgraded outputs would have helped. I bought the unit from a local friend who had upgraded 845’s. His comment to me was that upgraded outputs would help, but not significantly alter the presentation.
I had a number of good amps to compare to at that time. Allnic M2500 PX25, VAC 200iq, and shortly after the Thomas Mayer. These were the “direct compares”. It wasn’t close. Either of the push pull amps went way beyond what the LM845 could do in the HF and resolution department. But this is something I really hone in on for certain types of music which are rich in this content. Vocals? No. 1950’s jazz? No. Electronic stuff with engineered sound stages. Yello, Kraftwerk, Radiohead, Can.
IMO, SET amps are best for vocals, jazz, and similar. The coherent, unconfused, midrange is the best there is. Natural and 3D. But there are compromises at the frequency extremes. Other amp types have better resolution and dynamics. I love the SET tube distortion flavor. Better than the SS amp distortion flavor. All amps have distortion.
When I got the Thomas Mayer and VAC 200iq in the same room, the two heavy weights knocked each other out. The TM exposed the VAC for having a contorted confused midrange, and the much higher powered VAC dynamically blew the doors off the TM and the bass and HF were much better. In the end I couldn’t live with either with their limitations exposed.
Pick the right tool for the intended job. I still haven’t found one amp that does it all. It’s ok to have a few.