Sonus Faber Sonetto 8g2 - amp pairing

The Sonetto's are somewhat demanding (4 Ω nominal) but 90 dB sensitivity is decent. So you’ll want an amp that handles low impedance loads well. Recommended 50 W‑400 W means you have a lot of headroom, if you run at moderate listening levels you might get away with less than 50 W, but if you push dynamics or room size is large, more power helps.

Given your goals being “warmth, more musicality, smoothness, engaging/exciting, all‑rounder, analog as main but digital also”, my pick in your list would be the Qualiton A75. It strikes the best balance of “tube warm/engaging” + “sufficient drive/power/headroom” for your speakers. 

The Qualiton gives you a strong tube flavour, smooth voice‑centric richness, and enough power (75 W Class A) to drive the Sonettos in many listening situations, especially if your room isn’t massive and you don’t push extremely high SPLs or heavy bass‑extensive music constantly. If you listen moderately and want the “tube musicality” as a priority, this is a very good match.

My budget? Well im from europe, so: 

1) Qualiton 75 is affordable, it costs 6,7k EUR, 

2) Cayin Soul costs around 9k EUR, 

3) Jadis around 11k EUR (it is expensive for me, if difference vs. Qualiton in sound signature doesnt justify its price - it is out of scope)

At the end of day, point one and second are my top picks. Qualiton is significant cheaper, and i can even squeez more from this piece by switching to KT88 and lions. Jadis is being to expensive for me. Gear might be new or used.

My other gear: phasemation ea-320 + Rega P8, Lab12 Dac1 ref + holo red, all wires - Ricable dedalus. 

Room is in L shape. Gear is being placed at the top of longer side of L. Longer side has around 28m2, rest ca. 20m2. Im siting around 2,5-3 meters in front of speakers.

Thx Gents! 

PS. Audioqualiton - both 50 and 75 - are not class A. They are AB. Only first few watts are A (confirmed directly with AH/Qualiton).

Synthesis Audio

Looking at the specs of your speakers they dip below 4Ohms with difficult phase angles, so some of your amps may well not be up to driving them fully.  Here’s an exerpt from Stereophile’s measurements of the Sonetto V G2 that likely has very similar specs in terms of its load on an amp…

The Sonus faber loudspeaker’s voltage sensitivity is specified as 89dB/2.83V/m; my B-weighted estimate was 88.6dB(B), which is within experimental error of the specification. Sonus faber specifies the Sonetto V G2’s nominal impedance as 4 ohms. The impedance magnitude (fig.1, solid trace), measured with Dayton Audio’s DATS V2 system, remains above 4 ohms for most of the audioband, with a minimum value of 2.9 ohms between 90Hz and 100Hz. The electrical phase angle (fig.1, dotted trace) is high at low and very high frequencies, which means that the effective resistance, or EPDR (footnote 1), drops below 3 ohms between 43Hz and 46Hz, from 65Hz to 203Hz, and above 4.3kHz. The minimum EPDR values are 1.95 ohms at 34Hz, 1.26 ohms at 81Hz, and 2 ohms from 6.5kHz to 7.7kHz. The Sonetto V G2 is a very current-hungry load for amplifiers.

This is a hard load for even a higher-powered tube amp, and I’d be looking at a hybrid like a Unison Unico 90 or 150 with a tube preamp section and solid state amp that can give you that tube goodness with enough grunt to drive your speakers properly without having to work too hard.  No amp sounds its best when it’s pushed to near its limits.  Hope this helps, and best of luck  

I'd check out the @abritishaudiophile7314 reviews on youtube. He loves to analyze amps and go deep into technical details.