Parasound A21+ or PS Audio S700 monos?


Since I have some time on my hands, I've been playing with my hifi.  And it's time for a new power amp.
Rest of system is an Exposure 3010S2 CD player feeding a Naim nDAC, an Exposure 3010S2 or Conrad-Johnson PF2L, speakers are Monitor Audio Gold GX300s. 

In looking and reading, it seems like the Parasound A21+ and PS Audio S700 are the leading contenders.  New S700 monos are $1798; a 1 year old A21+ is $2000.  

Thoughts on them?
naimfan
+1 for John Curl’s linear design Parasound A21+
The Parasound A 21+ offers a lot of low-distortion power and isn’t fazed by impedance’s as low as 2 ohms.—John Atkinson
Sounds like the MA gx300’s with ribbon tweeters need some grunt, judging by HiFi News and record Review
"Bear in mind you will need a good amp to drive them."

The Class-D PS Audio doesn’t get a mention into 2ohms in the Stereophile tests, this is usually the case when they fall off a cliff trying to do it.

Cheers George


I have A23 amp, which sounded nice, but man it could heat a room. The A21+ must be a who lot hotter. I had a pair of M700s that I really liked, but my Emerald Physics KCIIs are an easy load. If you’re patient you can pick up a pair at a great price
Underwood HiFi was running a special on Audio Alchemy/Elac amps which should be really good options, and more powerful (I think)
Today is the last day to get the M700 at $1,798 (with qualifying trade-in).Just an FYI
The a21 looks and feels like a much more expensive amp than it is and it the a21+ improves on the originals upper mid and hi fq resolution I would jump on it. My only experience with class D is peachtree tho’ and while they’re smooth I don’t get the listening impression they’re quite there yet.
I know this is a little dated information, I’ve had the original A21, ICEpower amplifiers at the same time, which I’ve seen in at least some PS Audio amps.

I could literally not hear a difference, so I sold the A21.

However, I finally swapped those out for a Luxman integrated, which bested both of them. :)

I did by the way like both the Parasound and the ICEpower amps.  Nothing wrong with them at all, they sound punchy and quiet and warm. Just not as good as the Luxman.
but man it could heat a room The A21+ must be a who lot hotter.


This statement above is not correct naimfan, A21+ idle or at low level listening is drawing only 160w from the mains, as much as 2 x 75w light globes and with the size of those heatsinks they would be only warm to the touch. This amp would have around 8watts of Class-A on it. Sure if you want to pump it up to party levels, then yes it will get hotter.

Cheers George
Doh!!! In the interest of brutal honesty I'd like to partially retract my previous statement. I owned the smaller, A23's not the A21s.

Sorry, my bad, I always get them confused due to the bigger number being the smaller amp.

My anti-fans will remember I made a mistake, while my fans will remember I corrected it.
Since I have the time, I ordered a pair of M700s (the fact they are made in the next town over is a positive!).  Should be here in a week or so.  The promotion ending today made that decision easier . . .

May also try a A21+ as several people have said they think they'd prefer it.  And if a Belles comes up I'd be inclined to buy it to try out. 

Other input welcomed!  I'd also be curious to try something like a Krell KST-100 - funny that a KSA-100 Mk2 is only $20 more on a well-known used dealer site!
What are you looking to improve upon, and what amp and system sound characteristics are most important to you?
OP,
I hope you get the Parasound too and after all are broken in you could post the shootout results Vs the PSA. That would rock!  I bet there are many readers who have considered these two brands and a good head to head would be most welcome if you are able to swing it
I owned the A21+. Loved it!  I “upgraded” to the JC5 and frankly can’t tell much difference in my setup. Can’t speak to the PS Audio, but I can’t imagine you would be dissatisfied with the Parasound.

Sidenote.  I had an A23 and wasn’t really happy with it. Many have mentioned it. It sounded very “thin” to me. 
I too was concerned about the A21+ and the heat but it never has gotten very hot, just warmish However I never drive it loud!
Hey naimfan - I have an a21+ powering a pair of Monitor Audio Gold 200 speakers. While I can’t speak to the PS Audio monoblocks, I am very pleased with my system. I stream through a Blusound node2 and also have a vinyl rig (Rega). I use an Anthem MRX520 as a preamp when listening to 2 or 2.1 channel. My next purchase will be a DAC to upgrade the digital experience. 
My a21+ does not run particularly hot - warm yes, but I’ve never perceived it to be heating the room. That includes during lengthy high volume jam sessions.  I bought it new a little over a year ago and have had 0 issues. 
bwaterme - I went back and forth between the JC1 and the a21+ and ended up with the a21+ to preserve domestic tranquility.  Based on your experience I guess it worked out ok. ;-)
You might want to look into a used Anthem P2 amp, plenty of power and able to go down to 1 ohm if needed, also even at ear splitting volume the amp never gets hotter than room temperature.The P2 amp is a very neutral sounding amp that neither adds to or takes away from the original sound of the music source.If you are near the Chicago area I would be happy to give you a demo listen.
Doesn’t ps audio offer a 30 day money back offer? Instead of relying on comments/opinions, bring the ps audio amps in for an in-house trial Using your equipment and if you don’t like them, send them back. I have heard good reviews on the 700’s. I have the ps audio Bhk amp and DS sr dac, and sound fantastic. Also with ps audio, you get very good support.
@feldmen4 - Thanks!  That's very helpful, as your speakers are pretty close to mine (or at least should be!). 

As mentioned above, I may just buy a used A21+ to compare to the M700s (incidentally, apologies to all for getting the thread title wrong).  And will entertain other amps as possible . . .
Another option is the Van Alstine Vision SET 400. I have had one for three months and really enjoy it. It alternates in my system with a PS Audio BHK 250.

https://avahifi.com/collections/power-amplifiers/products/vision-set-400-amplifier

Frank also has a 30 day return policy.
Attention All Readers:

Right now any deal that ends today
will be replaced by a better deal tomorrow.
Even if you were born yesterday.
Now is a good time to sell 
but not to buy. Unless you enjoy
overpaying.
Naimfan-Keep shopping.

@erik_squires
My anti-fans will remember I made a mistake, while my fans will remember I corrected it.
Erik, have any of your "fans" asked for autograph? LOL

@tweak1 There might have been an issue with your A23, my A21+ runs warm but never hot and my speakers are not that efficient. I have 5 amplifiers and I hear a difference in the sound produced by each of them.
Erik, have any of your "fans" asked for autograph? LOL


No, they only ever ask me for free drinks.
Well then, consider me a fan.  Scotch rocks please, not cheap well stuff.
Hello naimfan,

I think the A21 is a very good class AB amp but still think the S700s will equal or surpass the A21 in every single facet except price, size, weight, electricity consumed and excess heat produced. The A21 may be able to handle 2 ohm speaker loads better than the A700s, which is a strange and meaningless advantage to mention considering your speakers’ impedance never dips that low.
The S700s will have a much more neutral sound quality than the A21, which adds an intentional warm quality to the sound. Of course, it’s your decision which overall amp quality you prefer.

Best wishes,
Tim
I love my A21. No issues at all. I thought about upgrading to the A21+ or JC models but I’m gonna wait until I can afford a top notch Tube setup instead. Oh, I’m driving very efficient speakers as well now since removing Goldenear Triton 5’s our of the system, they weren't terribly inefficient but are less than the Cornwall IV’s. Happy Hunting! 
I had the A21 and now have the M700s.  For me and my efficient speakers, I'll take the PS Audio M700s anyday.  They just sound more lively and snappy to me.  I'm a little skeptical of the improvements from the A21 to the A21+.   
jetter
anything is possible, but even at idle I could not put my hand on it for more than a split second
naimfan

when I got my M700s they already had some hours on them, but still took a good 200 hours playing time to relax
Attn. Tweak1—
Re. Parasound A23, if your A23 is running HOT it’s either deficient (a defective part, or circuit improperly repaired or altered), or it is extremely confined and without normal free air circulation. A fully "in spec" A23 won’t ever get more than mildly warm, even when pushed fairly hard into a nominal 4 Ohm load (air circulation normal).

I’ve been an A23 user for the past 4+ years, and have never experienced appreciable heating, nor have the front panel overheat indicators ever illuminated. (What about your overheat LEDs?)

I’m also a longtime "seat-of-the-pants" audio engineer with extensive DIY circuit design, construction, and test experience, and I’ve personally had my own Parasound A23 up on my instrumented test bench to check power output, s/n, input gain, DC offset, tracking, etc. I find that this amp performs exactly as specified, and that it runs at a very normal (not hot) temperature. (A Disclaimer: I can’t check out THD anymore. That parameter is now too far below the residual distortion of my test gear.)

FYI, I’ve also fully reviewed the A23 schematic, and carefully inspected the internal construction. In my opinion, the A23 is truly an excellent power amplifier, with admirable design and execution. I especially like the care apparent in the power supply (lots of Zener stabilized decoupling), and in the DC servo circuit that optimally minimizes DC offset at the output.

In sum, if your own A23 runs hot (but has normal air circulation), I’m certain that something is wrong. I’d suggest contacting Parasound’s Service Dept.
Post removed 
In sum, if your own A21 runs hot (but has normal air circulation), I’m certain that something is wrong. I’d suggest contacting Parasound’s Service Dept.
Told him that way back, he doesn't listen, or has an agenda.

Cheers George
I have the S300 and like it but am interested how this turns out.  Might have to move up to the 700
Well, I have the Parasound A23 (obviously a model below the A21) and the stereo version of the M700 (the S300).  I find the S300 is superior in every regard - not in a really significant way, but clearly audible.  Cleaner and more articulate, the A23 sounds “thick” and less resolving in comparison.  
I’m guessing a similar difference would be heard between the A21 and the M700s. 
My $.02.  
Vincent Audio valve mono blocks Model SP T-700
Mine was in totally open air space. I purchased direct as a x dealer concession. It looked brand new. I sold it long ago
@mgrif104

I was considering Parasound when I bought my S300.  Then I talked to a person in the sales industry who was familiar with both and said to go with the S300.  Been pretty happy with it so far.  I matched it up with a Tube pre and a DAC that was reviewed as having “warm” characteristics.   I especially enjoy not heating up my living room in the summer.    Also PS is Audio is just down the road from my house :) . 
Hmmm . . . M700s now delayed until May, date unspecified. 

May have to consider Belles Arias . . .
Or a Belles 350A Ref, which should be on the way shortly.