*Abbreviated text posted:
https://www.head-fi.org/threads/fs-...edance-damping-controls.867632/#post-14027025
Got it, thanks to yaluen!
First impressions coming from not having an amplifier: many small improvements such as blacker blacks, authority, demasked clarity and more low end. I never expected my lessened hearing would perceive a difference, it's subtle but significant.
Smooth potentiometer (ALPS blue velvet), I can do perfectly fine adjustments on just one-fifth of practicable volume range. (Sensitive) Grados plugged in, the amp is hiss-free for at least two times that range; find me relieved!
Brushed finish aluminum, the knobs are powder finished. On/off rocker is next to the power socket on the back, a negative.
Through my low impedance sensitive headphones, my unit adds a faint, volume-independent buzz on HIGH–GAIN mode. Interconnects on or off, I tried different outlets to no avail (it's probably stemming from the amp, unless my 120 to 100V power converter is faulty; *NEITHER, Yaluen also experienced it on the EPA-007x). Mostly inaudible while music is playing and inexistent on LOW-GAIN, and probably a non-issue with less sensitive headphones (but I can't confirm).
[Impedance compensation feature]
From the manual:
0 = off*
LOW = headphones with 200 ohms or less
MID = with 200 to 500 ohms
HIGH = 500 ohms or more
(indicative values, experimenting encouraged)
*The manual states the “0” position nullifies the sound adjustments otherwise permitted by the “DAMP” deemer, but contrary to that I find it still has some effect but minimized.
This amplifier's volume can only be lowered to mere, but not zero.
*following text was replaced by: https://www.head-fi.org/threads/epa-007x-headphone-amplifier-–-phasemation-japan.612433/page-2#post-14010211
- Pushing up the IMPEDANCE stepped knob (from “0” to HIGH) seems to diminish damping (“expending” sound). On HIGH, SOFT DAMP sounds more “glassy” (regarding highs) and HARD more “boomy” (regarding lows).
- Pushing down seems to provide more “breaking force” damping (“focusing” sound). LOW and “0” settings are much less dramatic, they sound just like my headphone, no matter SOFT or HARD.
The sound while the DAMP knob in the middle (there isn't a notched position holding the position) is also changed by the IMPEDANCE switch position.
For a given step on the IMPEDANCE knob and as a general rule, SOFT seems to lessen damping and loosen sound, while HARD would increase and tighten them respectively. I like to think of SOFT as “Wet” (sounding) and of HARD as “Dry”. Wet seems to exacerbate the signature of your headphone through its impedance curve (in my case it overshoots the upper midrange), while Dry chokes it (flattening the spectrum). It either parodize or neutralize your headphone's personality.
So far I prefer DAMP all the way on HARD and IMPEDANCE on HIGH.
