Parasound A21 and A21+: Significant Improvements in SQ?

I have an A21 and wondering if  an A21+ would result in improved sound.  Mainly looking for a bit more refinement, maybe speed and clarity.....airiness.
These are the changes made in detail, all bodes well for what your asking of the new A21+

Improvements made over the older A21.

• The power has been increased from 250W to 300W into 8 ohms, with comparable changes into smaller impedances.

• Power supply filter capacitance has gone from 88,000ÊF to 108,000ÊF.

• Signal/Noise is up from 112dB to 115dB.

• Total harmonic distortion at full power has been halved, from 0.2% to 0.1%; at normal listening levels it's claimed to be below 0.03%.

• Channel separation at 20kHz has been increased from 63dB to 70dB.

• The capacity of the transformer has been increased, from 1.2kVA to 1.3kVA.

• Partly as a consequence of the above, the amp got heavier: 71lb, compared to 60lb.

• Cosmetics were updated with aluminum endcaps and gold highlights.

• The same heavy-duty speaker terminals used in the JC 5 stereo power amp were added.

• Internal audio connections were upgraded to gold on gold.

• The automatic turn-on circuit was improved.

Cheers George

I have the same question and also wonder how the A21 + fairs against the JC5, Also Is the new A21+ a John Curl update? One of the two will hopefully find its way into my setup to replace my A21 which really can't fault after its many years of wonderful service but the journey must continue.
Also Is the new A21+ a John Curl update?
To me it wouldn’t matter, as those updates are just bigger, more, better things to do to it, everything has a monitory max to it, the A21+ has more build budget so it's got higher retail cost.
Most of the differences are just over engineering differences, hence the higher costs. But the basic topology of the circuit design is still John Curl’s, and that’s the heart and that’s what matters, the sound signature should be more similar than more different.

Cheers George
Thank you George.  What I'm looking for is refinement. 

Its not good that it now weighs 70+lbs. I'll have to think about that.
While there are many ways in which the Parasound line excels, even the Luxman integrateds can make them sound constrained and too warm sounding.

Depends very much on your speakers though, with B&W, Focal, Dali or GE I would imagine the Parasound is a better match.

The speakers I'm listening too the most are the B&W 705 S2 and the Elac Uni-Fi UB5. 

I am using a Class D Classe AMP2 or a Parasound A21.  The AMP2 seems fast and precise while at the same time a tad bright.  The A21 on the other hand is the opposite.  They are both very powerful and I like them both but I'd like to try a blend of the two.

Also, jdub39, you will find a comparison of the A21+ and the JC5 on Youtube. I expect I would like the JC5 but I'm not ready to drop $4K+ on an amp at this time.
I had an A21 then upgraded to the A21+. The + definitely had a bigger more refined sound to my ears. I’d say it was worth it. I then upgraded to the JC5. I’d say the JC5 had very little or no clear audible improvements over the A21+. 
I love Parasound products in general. But if I were doing it all over again, I’d get the 21+ and stick with it. Matched with a JC2 or I suspect many other preamps, and it is a beautiful sound. 
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.
If you like the Parasound sound I would just upgrade to a higher model. Or maybe Bryston.
I have the Jc5 for about a month now and the darn thing is still breaking in! Now having said that, this is just a first rate amp period! Out the box , I questioned the whole upgrade process, two weeks later I started upgrading everything around it cables,dac etc.. (JCP 2 bypass is being saved for as we speak) The integrity of the soundstage is so solid on a three dimensional axis., images are palpable, musical timing and flow can produce goose bump city. Volume be  it low level listening or cutting loose the music just remains stable and no hint of dynamic compression  just unbelievable. I"m so glad I went all in on the Jc5!