May I present the newest member of the high-amp.de family of amps for STAX - the ELECTRA, which I got to test, as I already own his SIRIUS transistor amp, as well as his ANTARES tube hybrid.
Technical data and measurements of ELECTRA is here at its maker, Andreas Rauenbuehler’s site:
http://high-amp.de/html/elektra_offer.html
Did a bit comparative A/B/C listening: Electra sounds a bit rounder and fuller as the drier sounding Sirius, closer to the Antares tube hybrid amp. Superb for Jazz and Vocals / Acoustic music; also great for Pop/R&B music.
The Sirius however is superb for Rock, Electronic, HipHop, Metal where more kick and a colder + drier sound is needed / liked. Classic also sounds good with the Electra but the Sirius has an edge above it at very complex forte passages.
ELECTRA runs quite cooler and needs no warm up time; it has XLR abd RCA inputs as well as both XLR / RCA passive loop through outputs.