Speed, detail and transparency are all pretty good and arguably superior in its price bracket. Bass is very good, maybe even excellent. Midrange is reasonably neutral, not warm, not dry. Upper end is oh-so-slightly tizzy, can be ameliorated by a tube preamp. Excellent buy, esp used. Very good support from the company. I sold mine to go all tube, though if I had to get an SS amp I would look at this one again. The companion preamp is highly featured but the lesser performer of the two, I thought a touch on the dry side. I understand the GCC/GCA replacement is noticeably better but no personal experience.
All of the above IMO/IMS.
Agree with Kck on all counts (re: HCA-2). The upper mids on up can be improved, if desired, with simple cap and wire upgrades (see thread at Audio Asylum, or these can be done by a modder like RAM). There's some stiff competition coming out from the likes of Nuforce, Bel Canto, CI Audio and others in the inexpensive but excellent-sounding digital amp parade, but if you're looking used the HCA-2 is tough to beat for the price.
Agree, with Kck and Richards. In my case, a particular asset is the HCA-2's indifference to the low impedance of my Maggie 1.6's. I use the HCA-2 with a tubed preamp with adjustable gain. The pre sounds best set to it's lowest gain, so the rather high gain of the HCA-2 is a benefit in this scenario. I had been rather frustrated with the 1.6's until I tried the HCA-2. It has proven to be an excellent performer, especially for the price. I did have some problems at first that required a trip back to the manufacturer and I have received excelllent, fast service/support.
Photon46, you reminded me that the HCA-2, against my 4 ohm speakers, succeeded in driving them with ease where nominally more powerful amps had shown weakness. One could do a lot worse for the money, well under $1K used. I can't imagine this amp would not benefit any moderate (under $5K total) system. Kudos to PSA for being one of the first to execute such a design with grace, style AND economy.
VALUE!!! While my HCA is no longer my primary amplifier, it's now powering my outdoor system. Decoupled the transformer from the chassis, Black Gate caps, and a beefy DIY shielded AC chord, made a considerable improvement. I wouldn't hesitate to suggest a used one and have the full RAM mods done.
I didn't experience any of the high or mid range issues mentioned above and I went from a tube preamp to solid state/battery. Upgrades in digital playback, phono cartridge, and speaker system, were clearly noticible using the HCA. At first the bass seemed only slightly thin until I compared it to a couple of amps that are famous for their bass reproduction and upgraded my preamp. I preferred the more precise rendition of the HCA, and I'm not calling it tight, rather much more accurate in timbre. While the other two had more of that flabby bass that many seem to enjoy, the HCA has the ability to start the note quicker than the others, IMO.
I agree & think the HCA-2 represents a tremendous value. With careful component matching as well as trying different interconnects, especially power cords, one can really bring this amp/your system to its full glorious potential, your efforts will pay off! Finally the HCA-2 should be tried in its true balanced mode, taking what already is a very good amp to even higher levels of sound reproduction. Currently I have no desire to look any further than this amp, no wonder Stereophile magazine gave this amp a class "A" recommendation!
Some of the review pointed out that the self noise level is high. And wondering if lower self noise level would bring out more magic out of this amp. Any comments on this? Thanks...
Zt000, these tests & specs have little to do with sound quality since most quality amps are designed by ear, not by laboratory measurements & specifications. I always thought the HCA-2 was one of the best efforts as far as producing a digital amp that created the least amount of noise. If there is any audible noise I can't hear it.
most quality amps are designed by ear, not by laboratory measurements & specifications
Drubin, tube gear has horrible specs/measurements when compared to solid state but there are alot audiophiles that prefer the tube sound. Engineering a product & applying large amounts of negative feedback (a common practice on cheap gear) results in a product that reguires less attention to circuit design and they always have better specs however they fall short on sound quality. I'm sure when Stereophile evaluated this amp, their conclusions were soley based on sound quality & not lab measurements. Forget the specs/measurements, believe your ears.
I was shocked when I had this amp home. It sounds harsh and muffled. I was not surprised when I read the reviews detailing its poor (measured) performance. The unit is also grossly overpriced given its parts count/quality.
Nightdoggy, my findings & others as well as Stereophile are the dead opposite to yours as you can tell but I recognize the fact that not everyone is going to like the same product (system compatibility). What preamp, power cord, & interconnects did you use with it? The HCA-2 has only two gain stages with the output stage being digital. For that reason you can't expect a big parts count. Besides, the more parts a signal travels through the more it is degraded. When a straight wire with gain is invented that is where I want to be.
Hi I just purchased 2 of these to bi-amp my stereo and I wanted to know if the Ram mods are worth the $795 price tag? Do the mods make the amp sound like a whole new amp or is it a subtle difference?
It's very difficult to convey quantitative sonic differences but let me give it a shot. Prior to the stereophile review I purchased an HCA and my first impression was as Nightdoggy states above, 'harsh' and I might add thin in the bass. An Inmate suggested leaving it on but how long had not yet been determined. I set my player on repeat and left for a two week vacation. Upon returning the difference was indeed like a different amplifier. For the sake of this conversation if I call that a 100% difference then installing the Black Gates seemed like a 30% increase in refinement. I should add that the Black Gates took a very long time to run in and the amount seems to vary a great deal, so be prepared.
Even more refinement came in the way of metal clad VAC, shielded power cable, decoupling the transformer, mass loading the case, and suspending it. The RAM modifications seem to go well beyond my experience with the HCA.
Since you have two amplifiers it would be amazing to have one modded and have a serious comparison.
I would say the differences in my system were well worth $800. Of course, the better the rest of your system resolves, the more you will hear the differences. With that caveat, I'd say that all of the problems that 10Audio.com groused about in their review of the HCA-2 are dispatched. The amplifier is much more refined now. It's hard to quantify percentage of differences in change, we each attach more importance to various performance parameters. I'd have a hard time going back to a stock version now. Rather than decoupling the transformer, I fabricated a non-magnetic copper and stainless retainer system. It is too easy for the heavy transformer to slide around when pulling the amp in & our of my rack.