Little Milton, don't get too excited. Some here just like taking pot shots at the HCA-2.
I find it hilarious that many of the amps that are often compared to the HCA-2 are 2 to 3 times more expensive than the HCA-2. And if modding a product means the product wasn't "well-engineered" to begin with, then virtually every component ever discussed here has to be considered poorly engineered because they all get modded searching for better performance. Not to mention the manufacturer mods (upgrades) to their own products, i.e the Spectron I, II, and now III or the Bel Canto 2002.x or xx, xxx. I can't even keep up with all of the Bel Canto changes. I am shocked, in fact, that Spectron and Bel Canto had to come out with so many upgrades to their products since Nealhood annointed them as "well engineered". And the ironic thing is that the HCA-2 upgrades I did to the HCA-2 cost $75 vs. the Spectron and Bel Canto upgrades which cost several hundreds more!
I think you get my point.
Spend $75 in premium parts on a $1,700 amp and I suspect it will compete with any of the amps mentioned here. Oh, and BTW, in its stock form it kicks the crap out of the Bel Canto based on virtually every post I have read comparing the two.
Click on the Review section at AA and read the HCA-2 reviews and the follow-up threads. There is much good information there from posters who have actually done direct comparisons of the HCA-2 to other "well-engineered" amps. Either the balance of the opinions at AA are correct about the HCA-2 or the "drive-by" HCA-2 posters at the 'Gon are correct. Take your pick.
