The Decware Sarah

[Rensselaer]

Wondering if any members have taken delivery of a Decware Sarah (SEWE300B) SET stereo amplifier and could answer a few questions?
1. Does it play well without a pre-amplifier as advertised, or is a pre-amplifier essential?
2. The Sarah uses voltage regulator tubes for each power tube, the OC2 set drops 75 volts, the OB2 set unknown and the OA2 set 150 volts (if I read that correctly from their website). Apparently each set affects the sound quality greatly. Anyone who has received a set and tried them out able to comment on the sound character of each?

 

[oknotok]

I don't own the Sarah but for the lack of a better answer here are my experiences with Decware:
(1) I own both the Tori Mk V and Zen Trio Anniversary amplifiers and without a pre-amplifier the soundstage on them is somewhat compressed, lacks dimension and the instruments are missing body. With a good pre-amplifier (I have the CSP325) both are opening up and the music is much more fluid, instruments get palpable.
I don't remember the build log on the Sarah but understood that Steve Deckert did design this amp much more as an integrated (with input and driver tubes) and in his listening tests he didn't use a preamp. I'd say a preamp is non-essential but you can add one later to your liking.
(2) Yes the VR tubes are wonderful to swap and the difference between them is substantial. With the standard OA3 the sound is modern, neutral and fast. With the OD3 I am getting an old vibe, wooly and lush. To me the OC3 is somewhere in the middle, relaxed and musical and I can listen longer without fatigue. You can also play with different rectifier tubes but their influence on the signature is less, it can improve the bass and highs. Then you can start to make combinations till you get the right sound for you.
The Sarah has smaller VR tubes for the input and driver tubes (not the power tubes) but the outcome will be the same - just add all variations to your order and experiment.