Prima Luna Vs Accupahse

You say you want a "rich, warm sound". I replaced a pair of Tannoy Turnberry SE that I had for 12 years and used with many amplifiers/preamplifiers/integrateds with a pair of Focal Kanta 2. Most recent amplification was/is Benchmark HPA4/AHB2, with both Tannoy and Focal. The sound with the Tannoys was certainly warmer, but I'm a lot happier with the Focal sound. Much clearer, much more detailed. More bass (as opposed to "warmth", maybe). In my room, anyway, the Focals have it all over the Tannoys. What am I saying, exactly? I guess partly that you will definitely get richer and warmer sound with the Tannoys. But it sounds much more like real music here with the Focal speakers. Listening to the Scottish Chamber Orchestra right now with them. Beautiful.

I've owned the SA20 and I now own a PL EVO 300 preamp, which feeds a pair of Belles Aria mono blocks.  I'm sure you already know to take advice here with a grain of salt, but I never liked the SA20 because, unlike the broad consensus, I found it very edgy and fatiguing.  So I too was looking to upgrade to a warm, rich sound.  Let me tell you, the Prima Luna preamp was a gigantic step in the right direction.  It is very refined, with a smooth midrange and helps throw out a very wide and holographic soundstage in comparison to the Arcam.  But keep in mind that my amps are pretty rich and full-bodied too.  Nevertheless, I'm confident the PL will help get you closer to that elusive "ideal sound" that we nutty audiophiles chase after.  I've never listened to Accuphase before and have only ever seen anything from that brand during a recent trip to Japan.  I don't know if it will get you closer to Nirvana than PL, but its "cool factor" alone (if that matters to you) is off the charts and would weigh heavily on my decision.  Good luck and happy listening!

I don’t know about the accuphase, but others seem to like it and it has a great reputation. The PL, to me, is a boring sounding tube amp. You can do much better for that money. Do you need that much power? I would investigate PASS, AYRE (both ss) and VAC, if accuphase isn’t already a done deal.

I had Accuphase, think it was E213, their entry model, and for that price you can get mid-high PrimaLuna models. So hard to compare, where Accuphase begins, Primaluna almost ends:)

Also, quite different sound. Went from Accuphase integrated, to Primaluna preamp+Pass labs power amp, to now Primaluna 300 Hybrid. 
If you want clean musical sound and brand name/resale value, Accuphase is way to go. If you want more organic and holographic sound but with good bass grip, 300 Hybrid is great choice. I love mine and finally don't have upgrade itch.
But all are great amps, you can't go wrong with any. 

I have a PL Evo 400 into Dynaudio evoke 50s.

I have the ability to upgrade, but no reason to want to.