I just compared the Proceed HPA2 side-by-side with a Bryston 4BST, and here are my impressions:
The Proceed has a cleaner, clearer sound than the Bryston. It really doesn't have a sonic signature (at least in the midrange and bass). The HPA2 stays out of the way, allowing the music to flow. As far as resolving detail and ambience, the Proceed was the hands-down winner.

However, the Proceed is brighter than most high-end power amps. Not quite as bright as the Krell KAV-300i, but definitely not as warm as Classe' or a tube power amp. Although the highs are smooth, the HPA2 can sound "thin" on bright recordings. If you have other bright components or speakers, you may notice the HPA2's brighter sound.

Except for the brightness, the HPA2 would get 5 stars. Rating 4 stars due to the brighter tonal balance.

I own the HPA2 and HPA3 (which both sound the same) and have compared it to Bryston 3B and 4NRB, as well as a Mark Levinson 336. Speakers used were Revel Salons and Vandersteen 2Ce (comparing with Bryston 3B) and Dunlavy SC-V (comparing with Bryston 4NRB and Mark Levinson 336). All HPA2 comments apply equally to the HPA3 since I can't hear any difference between the two.
I've owned the Bryston 3B for many years and wanted to get into home theater. I bought the HPA2 & 3 and spent several weeks feverishly comparing the HPA2 to the 3B. My first impression was that I liked the Bryston better because it seemed to have more high frequency information. I couldn't hear any more detail from the 3B than the HPA2, but it did seem like there was more going on, as if the "spaces between the notes" of music were filled in, but missing or diminished on the HPA2. After a little more listening I realized what I was really hearing was a fantastic silence in the HPA2. The HPA2 is like a Rembrandt painting: light emerging from black to reveal all the details in full contrast. The 3B and 4NRB are like Monet: plenty of light and color everywhere, without much dark silence in-between. As far as the sound is concerned, I can't say the Proceed is better than the Bryston, or vice-versa. They are both excellent amplifiers, but produce drastically different sounds.

I compared the HPA2 with the ML 336 and found the 336 to be a bit more transparent and airy. It required many trials switching back and forth to be absolutely convinced that there was any percievable difference between the two: they're that close. I've also compared the 335 to 33H and found a huge difference. The 33H sounds as big as it looks.

It goes without saying that the HPA2 & 3 construction quality are top-notch, and they integrate very well with other Proceed gear. I found a slight improvement (more open and airy) when using Balanced inputs vs. unbalanced. The HPA2 sounds great for both home theater use and music and offers as much detail as any other amp I've heard. This amp has a very pure, crystal clear sound and draws sound from silence like light from darkness.

Every amplifier has a different sound. I have yet to hear any two different amplifier models that sound the same. Given this wide variety, I find it very difficult to decide which amp sounds "best". However, I can say that I very much like the style of sound produced by the HPA2 and, considering how similar the sound is to the 336 (suggesting the Proceed is a good value), how well it integrates with other Proceed gear, construction quality, power, reliability, flexibility, and big, full sound in theater use, I give this amp 5 stars.

Very low noise manifesting itself by being dead silent during quiet passages; even at the highest volume levels.

Plenty of power reserves supplied by the 100 Volt DC power supply that will work well with the most inefficient speakers.

It can be upgraded to the 3-channel HPA-3 because it is a mono amp design and the chassis between the two is the same.

The speaker terminal connecters are of inferior design, but they are relatively sturdy. For everything else on the HPA-2 being excellent, Madrigal could have used better connectors given the price asked for this amp.

This is a 2-channel amp that is rated for 250 Watts @ 8 Ohms and 500 Watts @ 4 Ohms.

My setup:
I'm using the pre-outs on the Marantz SR-18 THX receiver to drive the HPA-2. The SR-18 is in analog bypass using input from the Pioneer Elite DV-F07 DVD player utilizing the Pioneer's internal DAC. The interconnects are all 1m Tributaries SCA 150 cables with glide on RCA connectors. My speakers are the Snell Type C/V that have 2-8" woofers, 2-5" mids and 2-1" tweeters. The speakers are 90 dB efficient and 250 Watts @ 8 Ohms.

Review:

The HPA-2 is very detailed and has a large soundstage. It is not bright as some people claim, rather it will reveal if your electronics or speakers are inherently bright. It does everything just right with proper bass, mid range and high frequency information. There is no coloration and music whether it is instrumental or vocal sounds like music and not electronics. What is amazing is that even at the highest volume levels the HPA-2 is dead silent in comparison to the Krell. There is no hiss whatsoever. The HPA-2 does not get very hot because of its massive heat sinks and good ventilation system, this is something you can't say about the Krell.

The bottom line is that the HPA-2 is great for everything from hard rock to classical and jazz. The next step up would be to go with actual Mark Levinson amps that costs thousands of dollars more per channel.

Similar Products Used:

Krell KaV-250a
Rotel 991
Not used, but evaluated the Bryston 4B-ST.