I did a pros and cons based upon my thoughts of the HPA-1 amp:
After several days with the HPA-1 and having a really GREAT time with it over a wide variety of headhones and dacs…(just got thru using that great measuring Topping D90!) I can say the amp is about as perfect as one could engineer and build.
But like all things there are things I do not like about it, which IMO may or may not be of a concern to you?
So here is “my” pro and con list:
PRO: Great Specifications, Transparent, Ample Power. Balanced and SE Inputs, Easy to understand and use front panel layout. A nicely visable mark on the volume knob to help see where the actual position is…some amps dont have this !!
CONS: PRICE, less than desireable case…like an advanced DIY case IMO. No XLR output for XLR balanced headphones. 2 yr warranty, even the sappy verbiage manufacturers have a 5 yr warranty on their “good” stuff and even Monoprice has a 3 yr warranty on there $400 THX AAA amp?
Even though an amp has spectacular measurements there are a few more things to look at other than the numbers!
Alex