OK, I have to confess - instead of single-ended pure A, I went for push-pull AB (first 4w A)
following hindsight from Goldwerger of his Taboo at 6w and opinion on rws 2.3w, coupled with the opportunity of a preloved 8w ecl82 tube amp made available, this is my opinion of a lower-than-iESL-specified-input-wattage, after few days of tempering and listening thru my airbow SC-1
Previously I was on same setup except thru SS amp of 200w AB (1st 10w A), iESL bias set betw 500-540v (experienced too much gain at 580v), impedence betw 96-64 ohm. It sound punchy and dynamic, truly bringing out the best of eStats headphone with sonic quality of the amp output.
With the 8w tube, strangely I noticed early onset of distortion to some songs. Setting at "normal" Stax bias of 580v solved this. My PCM63P-Y DAC/Preamp was volumed at 1 clockwise (2pm max), with vol control mostly on the AN izero.
another slight change made was XLR (from DAC) to RCA (into izero), (previously xlr bal into SS amp), although the typical 4v 2v issue is not prevalent in my case (had tested another dac with RCA output and did not notice diff)
1 thing i noticed; with low wattage output amp, when I need to turn up the volume, it may have reached the limit of the amp output sooner (and not nec at full vol) before it sound congested or even distort. But within it's sweet spot, there's just magic sweetness sprinkled into the songs/music.
Having said, with this tube amp, I may just started another journey of transition; from a audiophile back to just loving music as it is, tapping my feet & snapping my fingers along with it
, so much so I am now looking at budget sensitive full range speaker to go with this amp.
Oh yes, I also took the opportunity of hooking up short solid cores from iESL speaker output to my sr1a box, which offers a different sound signature to SS. Somehow I managed to up vol higher than the airbow before sound get distort