This is a post from one guy in Parasound group in Facebook I just past it
JC 1 vs A 21
I have been happily running the A 21 ever since 2011. About a year ago I got new speakers and I thought it would be a good time to upgrade my amp. I went through several amps, but I could not find one that I liked better than the A 21. Well, I finally did.
It all started a few months ago when Parasound released new versions of the Halo amplifiers, the A 21+, the JC 5, and the JC 1+ monoblocks. I tried the JC 5 and I frankly hated it. Not only did it sound worse than the A 21, it didn’t even sound very much like it. I am drawn to the conclusion that the JC 5 I got was a lemon, perhaps a factory second (I purchased used on eBay). Then, a few days ago in an episode of Paul MGowen’s daily videos, he claimed that, all else being equal, monoblocks always sound better than stereo amps. It occurred to me that with the release of the JC 1+, there might be a lot of original JC 1 owners lining up to upgrade their amps. I went on to Audiogon and, sure enough, I found 3 or 4 used JC 1s for sale. For a variety of reasons, I didn’t find any of the available units appealing. Either they were too old (some as old as 17 years) or they were too expensive with no attractive financing options. Then I thought about eBay. This where I had bought the disastrous JC5, so I was a little wary. I quickly found a pair of JC 1s that were low mileage (they were store demos), fairly new (2016 models), and were available for good financing terms under PayPal Credit. I pulled the trigger
The amps arrived last week and I have spent many hours listening to them. First, unlike the JC 5, I was surprised by how much they sounded like the A 21s. They were clearly designed with the same basic DNA. In my now approximately one-year amp hunt I always ran across the same problem. I found some amps that I thought equaled or exceeded the A 21's musicality, but lagged behind in dynamics and rhythmic slam (Pass X25, Coda Continuum No. 8, and the Yamaha A-S2100). Or, the amp equaled or exceeded the A 21's dynamics, but lacked its musicality (JC 5). Finally, in the JC 1 I found an amp that exceeded the A 21 on both counts. In terms of dynamics, the JC 1s throw an amazingly large soundstage in which both the attack and decay of transients are more intensely felt than with the A 21. Also, the bass is amazing, both impactful and highly articulated. This is not surprising. Compared to the A 21, the JC 1 offers 60% more power and over double the current. They were perfectly matched for my speakers, the Tekton Ulfberhts, whose strong suit is already the ability to throw a large, life-sized, soundstage. The JC 1s managed to do this without sacrificing any musicality. In fact, in the high output of pure class A meant they were actually MORE musical than the A 21. The amps have a sweetness and coherence that clearly exceeds the A 21. The Ulfberht is a reasonably efficient speaker. I measured 89db w 2.83 volts @ 1 meter. This means that paired with the Ulfberht the JC 1 can produce 98db in pure class A in its low bias setting. I never listen that loud. At my listening position I measure about 90db, which means the JC 1s never leave class A operation. It was this combination of refined high-end sweetness along with low-end grunt and slam that I had not been able to find in any other amp.
Interestingly, at the end of the day, the JC 1s simply don’t sound that much different from the A 21. They offer a nearly perfect example of diminishing returns. For double the price, I got an amp that sounds more like the A 21 than different from it. Brand new they would have been triple the price. True, the JC 1 sounds maybe 30%-40% better (it is hard to quantify this), but in terms of bang-for-the-buck, the A 21 is clearly the superior buy and I think the sweet spot in the Parasound Halo lineup.
I am satisfied that I could not have a better amp at anything close to what I could afford. Here's the JC 1s integrated into my system.
