Mods for a PS Audio HCA-2?

Total parts cost for the three levels of mods came to $500. That included quadruple runs of the Audio Consulting silver wire and cotton sleeves, four Black Gate caps in the signal path, five Jensen caps in the power supply, along with four Harris FRED diodes. Two other Black Gate caps (1000 uf) were also installed when the power supply was upgraded, but I don't know their function. The price also included a couple feet of silver hook-up wire to install the four pole Jensen caps.

You should re-read my post above, because I think the upgrade to the power supply was very significant- just not as much bang for the buck as the first two upgrades, which were relatively inexpensive. The upgrade to the power supply improved macro dynamics, lowered the noise floor, and also made the amp more natural sounding. Since I also upgraded the diodes and the two other BG caps at the same time, I can't precisely say what change resulted in what sonic improvement, only that the end result was worth the money spent.

I should also mention that I'm powering the HCA-2 with a P500 using the Multiwave I setting, and I'm using PS Audio Statement power cords. I mention this only because this amp MUST have good power going into it. To get the same results I got, you've got to feed this amp clean power. I find the new Multiwave makes a big differnce, with MWI giving this amp huge air and a sense of space to the music (oddly enough, my TV much prefers MW II).

So that was also part of the reason I upgraded the HCA-2 power supply- I was already aware of the way this amp responds to improvement to the power going into it. I figured without taking the final step, I'd never get the full potential this amp is capable of delivering. I think my educated hunch was correct based on the results.

And as a final thought, someone in the above thread mentioned how the Jensen caps are preferred in the power supply application over the Black Gates (which are better in the signal path). This is the same advice I got from the guys at Reference Audio Mods, so don't think just because the BG's are more expensive that they are always better.

One more thing I should mention. Paul Mc Gowan was asked on the PS Audio discussion forum about the difference between the HCA-2 and the Classic 250. He said that the HCA-2 does some things better than the Classic- I think he said faster transients, and more linear response among other things, but that it could never have the "weight" of the Classic 250.

I remember that comment because the mods I made to the HCA-2, really improved the "weight," making almost everything from piano, drums or the full orchestra have a power and realism that just wasn't there before. I can now listen to a piano, and the left hand notes are now room-filling, big, round powerful notes. Kick drums shake the room, but in a very realistic way, not just a big sloppy thump. And when an orchestra gets going, it makes the hair stand up on you neck- just the way it's supposed to.

One other minor tweak I forgot to mention in the previous post was removing the mounting bolt that runs through the center line of the torroidal transformer. This simple mod gives a more open and airy sound. But you absolutely must use extreme caution when moving the amp around, because if that transformer gets lose, it will do some serious damage!

So to conclude, I think at $1695, the HCA-2 is a great amp for the money. But add the $500 of mods, and now it's just a great amp- period.

I was intrigued to come across these comments about the improvements the mods make, because they sound like what I might be looking for. I've owned an HCA-2 for a few months now, and while I don't regret the purchase -- I'd find it hard to go back to a conventional solid-state amp now -- I've been bothered a lack of body and texture in the mid-range and upper bass. Sort of a thinness or hollowness.

Using a PS Audio Statement interconnect between the pre-amp (Marsh p2000) and amp somehow seemed to help to fill in the texture a little, but I'm still looking for more. I'd appreciate any further thoughts on what I might try next. Have other HCA-2 owners found the mods to solve the kind of problem I'm having? Or should I try other things first, like a different power cord (right now I'm using a LAT)? For the record, the rest of my system comprises an Arcam CD92 and Thiel 2.3 speakers, with Acoustic Zen Matrix Ref IIs between the CD player and preamp, Acoustic Zen Satori speaker cables, and a PS Audio Ultimate Outlet to the CD player.

Thanks for any tips.

The thing that folks need to understand about stock components is that they may have great frequency response with a steady-state signal, but they usually have dissapointing transient response. Mods are the only way to fix this. Power delivery to the active devices is the problem. The capacitor types and locations, the wiring topology and wire types make a huge difference here. A typical sotck amp may have great bass response and reasonable mid-band transient response, but lousy high-frequency transient response. Unless the transient resopnse is UNIFORM at all frequencies, the music will not sound live.

Steve N.
Empirical Audio
Manufacturer
http://www.empiricalaudio.com

Naunc, I have never heard your speakers so I am speaking totally out of school here, but what I have read on this board and others is that what you are hearing, many others have iterated about Thiels.

Before I get any Thiel owners upset, I am not saying they are not great speakers, but I think it comes down to one's preferences when listening to Thiels as with many other speakers.

I don't have the issues you describe with my HCA-2, but in fairness, I have done some mods to my amp that did greatly improve the amp. Unfortunately, it has been so long since I heard my amp stock that my lack of aural memory doesn't allow me to specifically address the stock sound of the HCA-2.