I own the Audion Black Shadow 845 SET monoblocks, and the Audion Golden Dream 300B PSET monoblocks. I have each pair in a different system, but switch each between systems frequently. I've also heard the 3-box Elite in my system and a recent pair of Black Shadows, though I am told the pair made a few months ago are not full Mark II, which are just now entering the market. So I can't yet comment on the very latest version, the just-completed Mark II update.
My own Black Shadows are seven years old, and my Golden Dreams about ten years old. The Black Shadow have silver audio path wiring, but as far as I know, copper-wound transformers. The Golden Dream have silver wirepaths, and silver-wound transformer secondaries. These are "Level 6" Golden Dream. Two improvements have been made to both. A couple of years ago, seeking better bass discipline, I asked Bob Hovland to examine the amps' circuits, listen to them, and recommend component upgrades. He chose to leave the signal path alone but to change out the power supply electrolytics to Nichicon, specifically tall, slender Nichicons. In the Black Shadows, he found he could considerably beat the factory hum noise spec via custom shielding of the toroidal power transformer, so I had that done as well.
The recaps made the Black Shadow pair "more like themselves" without dramatic changes to overall signature. They just became better at what they were already good at: bursty, objective, expressive, toneful sound with deep, muscular bass, blissful midrange realism, spatial honesty, smooth and extended top end; convincing tonal and dynamic realism on my Zu Definition speakers. The recaps instigated a much bigger improvement to the Golden Dream pair. The GD is an ultra-resolving amplifier that's also loaded with expressive tone. But the stock GD, like most 300B amps, brings with it some bass bloat, which varies by what tubes you use, but it's there. That euphonic fatness in the bass certainly fills a room but it's sloppier than it ought to be. Above 70Hz or so, fine. Below that -- and on something like a Definition, this is obvious -- bass loses objectivity.
Well, not so much if you get Hovland's Nichicon recap. Suddenly mesh plate 300Bs that were unusable on Definitions became disciplined. KR Audio 300Bs that were "hard" sounding and lean, became energetic and toneful.
The Black Shadow and Golden Dream are both rated 24w. Both use triodes in single-ended topology. Nevertheless, their sweet spots are a bit different. The 845 tube gives the Black Shadow more drive, energy and momentum than the 300B paralleled. The Black Shadow can tonally tune the system by your choice of 845 tube, but the essential assertiveness and explosive drive of the big-glass triode remains intact regardless. The Golden Dream has the edge in revealing delicate detail and in dimensional realism. GD tone is rich and holistic, fully formed aural "shapes" to distinguish even small differences in same instruments or voices from themselves. The PSET 300B config isn't weak by any means but the same watts are smooth and revealing, with less shove in exchange for more focus.
Both amps have all the speed and transparency Audion's tube amps are known for.
I've listened to SET amps much more expensive than Audion's two top models. For me, with 101db/w/m speakers that are also resolving and energetic, Audion's SET and PSET 845 and 300B respectively, are for all practical purposes, as good as hifi gets so far, and bring enough power to show it. For the past seven years I haven't heard amps by any other company I'd rather listen to and own.
Phil