If the VAC Sigma 170i sounds anything like the Phi 200 power amp, it will sound full bodied with a solid bass foundation, but lacking on transparency, sparkle and air in the mids and highs. I liked the Phi 200 with classical, jazz and blues, but found it lacking with female vocals and midrange magic. I'd be more inclined to search for a vintage VAC Avatar or Avatar Super with quality EL34 tubes... its a classic amp with a cult following for its midrange magic! If I ever go back to an integrated, the Avatar will be on my short list.
I've not heard any Octave products, but if you found the synergy to be exceptional with your speaker, keep it on your short list. Other tube integrated brands to consider: Line Magnetic, Cayin, Prima Luna and Jadis.
I've not heard any Octave products, but if you found the synergy to be exceptional with your speaker, keep it on your short list. Other tube integrated brands to consider: Line Magnetic, Cayin, Prima Luna and Jadis.