Mods for a PS Audio HCA-2?

Found this thread late, so most everything has been covered by Fiddler. He and I have shared notes on mods to the HCA-2, and in fact, he turned me on to Reference Audio Mods which had the best prices for the cpacitors.

Just to emphasize what's already been said, I did the mod in three stages. First, the output wiring was changed from double runs of stock Monster cable to quadruple runs of Jena Labs cryo'd 18 gauge hook-up wire. The improvement was far more than I had any reason to expect it to be. I've posted on this previously, on both AG and AA, so I won't repeat again.

This just whet my appetite for more, and talking to Fiddler I decided to change the four caps in the signal path to the Black Gates he mentioned. After a long break-in period, the amp had been transformed. I now felt it deserved it's Stereophile recommended component status, whereas prior to that, I didn't really think it was in that league.

I probably would have been happy stopping at that level of upgrade, since that represented the biggest, and highest value improvement. But with the amp now so much more revealing, I could hear a few things I wanted to see if I could improve upon. I decided after talking with Kyle at Reference Audio Mods to finish what I'd started, and he suggested Jensen caps to replace the large power supply capacitors. These are supposed to be a better choice for this application than the BG's, and have the added bonus of being less expensive. Since I'd also heard of another guy having a diode bridge rebuilt, I decided to go all the way and have RAM do the same (Harris FREDS). Since these caps/FREDS had to be mounted off the PCB, I had RAM do the work for me (I found they were only about 40 miles away from my location in So. Cal.). I dropped off the amp and the work was completed in a very timely manner (later that week).

The result of the last round of upgrades was more subtle than before, but significant and worth the price. The benefit was the noise floor of the amp had been lowered, and macro dynamics were improved. The HCA-2 also now had a more analog sound, for lack of a better description, and was was really overachieving- to the point that I had to have my Wadia 301 modified (also by RAM) in order to fully enjoy the upgrade to the amp. The Wadia upgrade is another story, but it was perhaps even more incredible. I didn't realize Redbook could sound that good.

I should also mention that I swapped out the Jena Labs wire for the Audio Consulting silver wire that RAM sells. Both sounded great, but the silver is now soldered in place, so I'm selling the Jena labs wire on AG in the next few days. I just want to put the disclaimer out there so that nobody thinks I'm hawking my Jena Lab wire when they see the ad in a couple of days. Both are good, and I'm sure others are too. The main point is this amp has a lot of potential beyond stock.

The bottom line is the basic design of the HCA-2 is great, just remove the most limiting price point components and you can move to a level of performance usually costing a multiple of what you've invested. It's a high-value way to get a high-end sound.

Wehamilton, What you had done, sounds alot like the mod package that's being advertised here on Audiogon. What was the entire cost, if you don't mind. I'm across the country, in Ct. I'd like to find someone closer.
Also, I thought that Fiddler said that the additional mods didn't result in that much difference in sound?
Sonny

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.