In use.
Like a piece of precision machinery, the Assistent 50 worked as the perfect butler: utterly dependable, without any quirks, annoying habits or ill manners. Bred to please was its MO. It operated dead quiet mechanically and electrically for neither transformer hum nor driver surf or hiss sans signal. The only noise immediately followed the soft-start cycle when a small sound appeared through the speakers only to fade quickly and utterly into oblivion. Remote volume worked flawlessly. Little increments were easily dialed without jumps. Even the light show was surprisingly subdued during the day, coming out to play only at night.

The circular back vents aren't for a fan but simply a passive air exchanger.

Whilst armchair engineers will have pondered the guts of the previous page to wonder about the power supply—it appears to be unusually small—veteran readers might remember the late Eduardo de Lima of Audiopax. This uniquely gifted valve amp designer from Brazil was convinced that each circuit had the ideal power supply. Anything beyond it wasn't just excessive and empty kowtowing to bragging rights. It was actually counterproductive sonically. This flew in the face of common wisdom where unending improvements are promised for bigger and bigger PSU; and where overkill is never on the map. Suffice it to say that Audiopax amps begged to differ from award to award; and that on bandwidth both bassment and attic, the Audio Valve really left nothing to the imagination. That its season was quite different from the 1MHz direct-coupled Linnenberg Audio Allegro monos flanking it in these photos was no surprise. If an all-valve amp sounded like solid state, why bother?


Juxtaposing Albedo Audio's Aptica and Amira speakers below created a neat parallel scenario in how what distinguished the ceramic-driver model from that with the cellulose tweeter and Curv mid/woofer closely tracked what separated the Assistent 50 from the Allegro twins. The ceramic Accuton drivers had more sparkle, speed, separation and incisiveness. The mate's were softer, moister and warmer as though their suspension was dialled for a bit more comfort than top acceleration and cornering stability. Even though the delta of difference between amps was larger on quantity, it very much mirrored the speakers' offset on personality type. Like the ceramic membranes, the high-speed transistors were quicker, sharper and leaner. Like the silk dome and fused polypropylene cone, the tube amp was mellower, denser, warmer and more saturated. What else is new the experienced tube hounds grumble?


The relative distribution of these attributes
. Clearly the Assistent 50 was no legacy-voiced 300B SET of limited bandwidth, with a very euphonic midrange, soft woolly bass and lazy reflexes. Purely on sight, the QQE 03/12 could suggest EL84/6BQ5 kinship. After all, those pentode minis are sized very similarly. Sonically however—and speaking in generalities rather than to unusual exceptions of implementation—they didn't remind me of any EL84 amp of my acquaintance. Those can get slightly piquant in the presence region. Whilst often very open and feisty but also a bit fiery, I've not heard them get as gloriously porcine in the bass as the Audio Valve managed on the big electric bass of Patrick Chartol's Istanbul album which in our library stands in brilliantly for Mercan Dede. Whilst the Audio Valve had the type saturation one gets from direct-heated power triodes, unlike them it wasn't allied to bandwidth issues. This was 'yes' for tone density and colour temperatures, 'no' to sluggishness and darkness. This butler had warmth and fluidity but no darkness.


It also wasn't an ethereal ultra-airy lit-up performer like a certain 45 SET in my past had been. It was nearly as dense but not as hulking as big 6550 monos had been. Perhaps the closest I'd heard were amps based on the 6V6. The Assistent 50 wasn't as fast as the transistor monos but had very unexpected kick on the 98dB Zu Druid V. Digging out bass-heavy and percussive fare with plenty of polyrhythmic drums and beat makers came like a hardwired reflex. It's not what ├╝ber gem├╝tliche pipe'n'slippers prejudices would anticipate for a valve amp. Where our German did behave unapologetically tube was with its relaxed attitude. The transistors felt more high-strung and tensioned. The QQE bottles were bodacious yet settled and never on edge. They replaced nervy adrenaline with strong colour 'pop'. This supported great solidity that wasn't about extreme ambient recovery. Instead, it focused on in-room hereness. Not to the extent of a wall of sound, its portrayal nonetheless veered in that massed direction. Sorting out the precise positions of five vocalists on a Vicente Amigo disc came off rather less specific than the lateral Exicon Mosfets managed. Conversely, these virtual bodies on stage were more flesh'n'blood gutsy than teleported in from a faraway recording venue replete with overtone halos and reflective trails. When time came to commit to the final review speaker, I settled on the Zu Druid V in a deliberate scenario of like meets like. This was a very compelling combo.