A Budget Amp Comparison



Budget Amp Comparison – Crown, Nuprime, Parasound


Everyone who begins their journey to audio nirvana probably begins the same way; with a bunch of research and wondering if they have spent “wisely”.

For those just starting out or just looking to make a change, this is a comparison of three budget amplifiers.  All three seem to have found a pretty good market following which probably means their price/sound performance is acceptable. Hopefully this comparison/thread will be helpful to new people entering the hobby…and hopefully this thread will invite comments from others who might have additional ideas about starter amps around/below $1000.

The three amplifiers are:

Crown XLS 2000/2 Class D ProAudio Amp - $499 new

Nuprime STA9 Class D Home Audio Amp with a Class A input stage - $649 new

Parasound Halo A23  high bias Class A/B Home Audio Amp - $995 new

(The most obvious amp missing from the group is the Schiit Vidar at $700 which also has a pretty good reputation and deserves consideration)

The other equipment these amps were paired up with during the comparisons include an Oppo 103, Parasound 2100 preamp, Tekton Lore loudspeakers, Blue Jeans RCA Cables and homemade OFC stranded, twisted, shielded speaker cables.


Crown XLS 2000/2002

The entry end for a new amplifier is probably $4-500 and the Crown is a pretty interesting amplifier at this price level. Designed by Harman International for pro audio applications but with consumer audio connections included as well (RCA inputs & banana/spade/bare wire speaker connections). This is a class D amplifier which Harman engineered to be powerful, reliable, clear, stable with tough loads and stable with crappy AC line voltages that might be found at a music venue.

The XLS 2000/2 has a surprisingly powerful low end, very wide soundstage extending 3’ beyond the speakers (but not very deep), decent midrange and top end. The Crown is silent with a black background and relatively musical overall.

A couple of great and really appreciated features include “no speaker thump” turn on and gain controls located on the front of the amp. The gain controls are fantastic when you have 98db efficiency speakers like the Lores. With no gain controls, you often only have the preamp/DAC at the 8-9 o’clock position and the loudspeakers are screaming…but if you also have a subwoofer that is connected to the preamp, you likely have to turn the sub gain controls all the way up which can sometimes compromise the sound. With the Crown XLS2000 you set the amp gain down allowing you to set the preamp volume up and your sub will sound its best. (You can also use the gain controls to equalize the left right volume if need be without the degradation you can sometimes get from balance controls).

This amp is insanely powerful…1050 watts into 2ohms per channel, 375 watts into 8 ohms and 650 watts into 4 ohms…bridgeable to mono with over 2000 watts. The input voltage required to drive to full output is 1.4 volts so it can pretty easily be driven directly by most CD players and DACs without a preamp.

On several occasions I emailed Crown with questions and always received a prompt reply that was helpful.

My overall feeling is that this is a really good starter amp for someone on a budget, for a second system, for a college kid, etc. Pretty good sound, bullet proof, tons of power, lots of connections, and all the connections needed for double duty use in dj applications and other pro audio type gigs as well as home audio…and less than $500.


Nuprime STA9

The amp is beautifully packaged and this by itself gives you a certain level of confidence as you open the box. In most (but not all) areas, the STA9 is a step up from the Crown. Although the soundstage presented is not as wide, it is deeper and more dimensional. Although the bass is not as powerful, it is more tuneful (better pitch). The midrange and top end have better definition with slightly better instrument separation. Head to head, the Nuprime sounds  more musical.

Both the Crown and the Nuprime are class D and weigh about 10lbs…but the Nuprime is about half the overall size. Nuprime says it designed this amp with a Class A input favoring 2nd order harmonics. This may explain why the Nuprime idled at 103 degrees and ran at 107 degrees while the Crown remained at room temperature and the fan never kicked on.  Like the Crown, the Nuprime is also dead silent and has a very black background.

A couple things I didn’t appreciate so much about the Nuprime: the on/off switch is on the back, it frequently thumped my loudspeakers when turning on and of (as well as when the oppo or the preamp turned on and off) and it didn’t have gain controls which made it much more difficult to integrate with the subwoofer.

The Nuprime is rated at 120 watts into both 4 ohms and 8 ohms and bridgeable to 290 watts mono.

Like with Crown, my email correspondence with Nuprime was always answered in a timely manner.

Based on sound alone, this amp is worth a try. You may not experience some of the things that bothered me…or they may not bother you.   If you don’t need the power of the Crown and you have a little more money to spend, this might be a good choice.

 

Parasound Halo A23

The Halo was also beautifully packaged (double boxed) with a very clearly written manual included. Parasound describes this amp as high bias Class A/AB…meaning that for the first watt or two, it operates as class A and then operates as A/B as more watts are used. (Pass labs has a very nice description of what actually happens http://www.firstwatt.com/pdf/art_leave_classa.pdf    )  I can’t say that I actually noticed any difference or if there was actually a change from Class A to A/B but I can say that in my system in my room, the Halo sound was a pretty big step up from the Nuprime (which was a step up from the Crown). The soundstage can best be described as immersive (deep and wide) with a strong, detailed low end, detailed and silky mids and highs with good instrument separation and very musically engaging.

Like the Crown and Nuprime, the Halo has a black background with no speaker hiss whatsoever. The Halo has a very effective relay that never thumped my loudspeakers. The operating temperature remained under 90 degrees for the first hour and then gradually climbed to 105 degrees by the third hour so ventilation may be needed. The Halo has gain controls on the rear and the on/off switch is on the front.

The Halo is rated at 125 watts into 8 ohms, 225 watts into 4 ohms, is bridgeable and will drive 2 ohm loads but not at full power at 20hz. Email response from Parasound was also quick.

If you can afford $1000 (new) or $700 (preowned), this is the best sounding amp of the group and deserves strong consideration. Another point worth mentioning is resale; Parasound has a good reputation and their products seem to resell pretty quickly on Audigon with prices that hold up pretty well over time.


Final Thoughts

Until you have a chance to try a piece of equipment in your home in your system in your room, you can only speculate as to what it will sound like and what quirks will drive you crazy. No matter how good the reviews and forum comments are its definitely worth the price of return shipping to try equipment for a few weeks before deciding.


snapsc
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Hi Snapsc,

Nice write up. Few notes. The Halo A23 is Class a for about the first 30 Watts, not 2. Well within the power envelope of most listening.

I had 2 of them. Measuring the power input, I think Parasound at some point decided to raise the bias point, because the idle current is about 2x what they are rated.

Second, yes, they are really nice amps if slightly warm sounding (a plus for me), but without anything unpleasant. No noise, no harshness, no distress at high output or with low impedance speakers. However, I did end up trading ICEPower Class D ASP amps for them. In my setup I could hear no difference, plus they idle stone cold, and were monoblocks, so had better channel separation, as well as true balanced inputs. Plus, I got a huge deal on the ICE modules.

In the budget range, I also think an Arcam integrated is a very good find, sounding closer to Ayre, in that they are darker.

Best,

E
Not sure what happened but the removed posts, not posted by me, had suggested one of the oddysey amps, khatargo, and van Alstine amps, synergy 200, both in the $1000 range... both seem like reasonable suggestions for this thread.  

Hopefully someone can comment on the specific merits for these amps...
Absolute Sound loves the Odyssey's, and there's plenty of info. over on Audio Circle.
This is a great thread - thanks, SnapSC!

I'm an audiophile on a budget (too many other priorities), so I appreciate reviews of budget gear. I'm quite happy with my vintage SA-12, but if I ever need to replace it, you've given me 3 alternatives!

Gasbose
I’ve got a Brio and a Nuprime STA-9 that I play with in a second system.  I’ve played each with at least close to a dozen speakers.  More often than not I prefer the Brio.  The Nuprime just seems to lack a little life to it.  It’s a very inoffensive amp, but just a tad too polite sounding.
I was wondering how the Halo 23 compares with the Schiit Vidar, which I'm partial to based on my impressions of the Schiit Bifrost, and on other factors.
More than a decade after widespread commercial acceptance, Class D amps are still widely considered to exist on the "low fi" end of the "hi fi" scale. Just about every thorough measurement exercise has confirmed that the pulse width modulation technique in amplifiers suffers from rising distortion at the upper end of the audible spectrum. Even some reputable longstanding industry people who manufacturer Class D amps have recommended against their use as "full range" amplifiers in high fidelity systems. When first introduced, they were hailed as near ideal solutions for subwoofer use. That too hasn't changed over time. They are still excellent for that purpose - clean, efficient, and reliable.
As for the Nuprime having a "class A" input stage, that's more advertising "hokus - pokus" than any legitimate feature that sets it apart. The majority of modern amp schematics I've seen for decades have shown a simple differential input that is Class A biased with quiescent current sinking via the emitters. Crossover distortion is and always has been a problem for output stages. Typically, what makes a good Class A/AB amplifier are Class A input and driver stages with an output stage that runs class A for the first 10 watts or so - switching to B when output swings to 10 volts or so.

As for the Halo A23, while it is a nice sounding well made amplifier, prospective owners should be aware that some of John Curl's dc coupled , wide bandwidth designs have suffered reliability problems. High frequency parasitic oscillation can creep in from a variety of sources in any high slewing rate, wide bandwidth amplifier. Undetected, it can result in widespread component damage and failure. The great sound is nice to have - while it lasts. Before one blindly adopts the "zero capacitor" signal path mantra, one should consider just how many excellent sounding amps exist that use feedback capacitors in the voltage amp stage for dominant pole compensation. Capacitance and inductance exist everywhere, whether or not such devices are intentionally placed in a circuit for a desired effect.  Careful management of these sources of energy storage is what separates merely good amplifiers from the truly great ones.
Musical Design amps by John Hillig truly are musical and reliable.  10 years ago I had a D-75 ( 75w/ch } which just played music, as if whatever solo instrument I hapeened to be playing a record of was actually in the room. Currently I have a 150B ( B model  has upgraded caps etc.)... my friend with the big Quad found were the most transparent amp he'd ever played on his 'stats.  "Nuf said.
Used, most of these amps go for under $1000 - if you can find one. 
If anyone is looking, another great budget amp that's not getting attention with reviewers is Class D Audio. Custom designed class D amps with great specs and sound. Made in USA, buy direct (no, I'm not affiliated). www.Classdaudio.com

SDS-470 has balanced inputs plus RCA, with adjustable gain. 2-ch amp for $695 provides 300W into 8 ohm, or 600W into 4 ohm with better than .02% THD.

This was my first amp purchase, very pleased with soundstage, and details. Powers a set of of Magnepan 3.7i admirably.

I have Audolici, Accuphase, Luxman, Audio Note, Rotel, Creek, Jolida, Marantz, Parasound, Technics and a few others, and the best sleeper amp out there right now is a receiver believe it or not. This is proof that mid-fi has caught up to High End Audio. The inexpensive Sherwood 4105 is a show stopper and name taker. Not stock, but if you ditch the feet, and put Tuning Blocks underneath, and a couple other free tweaks you'll be right up there with the big boys. Don't believe me, look at the testimonies of those who have gone from their High End goodies to this treasure.

Michael Green

www.michaelgreenaudio.net 



@michaelgreenaudioTuning blocks??? Will tuning bricks work or do they have to be "blocks"? Pine, birch, oak? Sealed and painted or au natural? Just curious what the other "tweaks" are... Isn't there a forum subsection that deals with "tweaks"? Or perhaps "tweaked" audiophiles...

Honestly, I was reading your post with some mild interest until you started talking about "tuning blocks". Seriously, there has to be a forum subsection for all the tweak faithful to go with their noise about magic beads, magic resistors, capacitors, cable, isolators, and every other conceivable "tweak" that provides "obvious" results that no one can ever seem to measure or prove with double blind testing.
Like many on this forum, I'm always interested in learning something new...so I googled "Parasound Parastic Oscillation" expecting I would find a number of articles and postings about the subject as relates to Parasound amplifiers...but I didn't.  "not sure what that means though"

What did pop us was an interesting article on the Hifisonix website reviewing in great detail the Ovation e amp...and several times within the long article, the author specifically commented how John Curl's designs had taken steps to avoid the parasitic oscillation problem...see link.

Since I'm not qualified to offer any electrical engineering/amp designer insight I will just say that I suspect that if this were a problem causing failures, Richard Schramm would have dealt with it long ago as it seems that he tries to run a professional, top notch company.

(I have no affiliation with Crown or Nuprime or Parasound)

http://hifisonix.com/ovation-e-amp/
As for the Vidar Halo comparison...you can read one such comparison on this website...they don't like the Halo but they really like the Vidar.  Having not heard the Vidar, I can't comment..but obviously, as noted in my review above, I didn't hear what they heard vis a vis the Halo.  In my system, it was open, punchy, deep and had a nice soundstage and presence with no bite or harshness.

http://www.superbestaudiofriends.org/index.php?threads/schiit-vidar-impression-thread-updated-with-r...

Hopefully, there are more people than can comment on their own direct comparison.


@snapsc   

    I don't think this thread should be turned into a Parasound bashing session but I will say that the causes of failure in a variety of equipment - not just amplifiers, are not always laid out in black and white on the internet for all to see. Parasound makes some very good amps - of that there is no doubt. However, their design philosophy hasn't been focused on "elegant simplicity" or reliability. At any given time, you will find a steady supply of Parasound amps for sale on Ebay listed "for parts" or "not working". Try an Ebay search and you'll see. Now do the same search using the words Krell, Threshold, Bryston, Plinius, Perreaux, or Pass Labs. If you find one or more than one, you would be lucky. Parasound circuit designs tend to be significantly more complicated than your typical Adcom, Perreaux, or Byrston design. And wide bandwidth amps have been vulnerable to ultrasonic oscillation since companies like Accuphase, Kenwood, and Harman began promoting the concept in the late 1970s. Whenever current or reduced capacitance feedback is used, the vulnerability increases - regardless of the claims made for thermal and over - current protection. Very few knowledgeable technicians are going to post online technical assessments of what they find. Bad mouthing an aspect of a particular company's products is simply not good for business. And basically, in Parasound's case, it's a design feature in much the same way that higher maintenance and failure rate is expected for a Porsche or Ferrari versus your typical Camry or Lexus LS430. Each design philosophy has its inherent strengths and weaknesses.


michaelgreenaudio:
is the sherwood receiver you're referring to the rx-4105? looks like a generic piece widely available for $60-70 used, but your rec is intriguiging....
@snapsc, thank you for taking the time to write up the reviews...very interesting.
I agree with drew_f, the  Class D Audio product line made in the USA is somewhat inexpensive, very tube-like in sound and does a great job all around. I have a Class D Audio SDS -470C with an upgraded power supply that's a keeper! Does a great job with my Maggy's 3.7 or my Montana EPX speakers.

Hi cj

Sorry about that. I tune all mine and clients systems, it's what I do and have done for 30 some years, so it's kind of weird for me to refer to any component without it's sonic context. It would be like you talking about your speakers without mentioning your room or amp.

I have a question for you. When you buy a component, do you leave it in shipping mode? Meaning do you loosen the cable ties, remove the top cover and loosen the transformer? I'm not trying to be a smart "A" here, just letting you know that there are all sorts of starting places audiophiles use to get their systems ready to play. For my gang, we would never play a component without removing the shipping restraints or do some of the very basics. Hey but that's what makes the world go round. Some people buy components thinking already about when they are going to sell it. And than there are others that use a component at it's best performance state.

Michael Green

www.michaelgreenaudio.net

Hi Loomis

Yes the rx4105. Here's a thread putting it into context. If you back up a page you will see what he replaced.

http://tuneland.forumotion.com/t415p50-lattis-system

Michael Green

www.michaelgreenaudio.net

@michaelgreenaudio.net

I suspect that most of us, especially as the price goes up, are reluctant to make any changes to a piece of equipment that might void the warranty...and therefore, usually not knowing what changes would be problematic, we leave things alone.

In my mind, it brings up another question:  A lot of gear is resold on Audigon...and sometimes that gear is sold with a particular tweak/mod which is described in the posting...do most potential buyers view these mods as improvements to the product or potential problems down the road that will be hard to get repaired and therefore avoid the purchase?
Maybe Michael will start a new trend here - all the owners of  " budget high end" electronics will dump their stuff on Craigslist and log on to Ebay to grab the next Sherwood RX 4105 receiver that comes along (to be "upgraded" with Michael's special isolating blocks, of course....) Alas, one more  perfectly acceptable thread gets hopelessly sidetracked with yet another crass commercial sales pitch... ugh .Again, Audiogon should have a forum subsection dedicated to these sales pitches for "tweaks". As always, self restraint is in too short a supply to keep the endless thread sidetracking at bay. We all get it. Everyone has their market niche and stuff to sell. No crime there. But as with anything else, there's a time and place - or at least there should be.
Maybe this will help get the thread back on track...for me, the big takeaway is that there can be a surprising sonic difference between budget amplifiers...therefore, listing as many budget amplifiers as possible (that people have lived with in their own systems) along with their sonic characteristics could be helpful to those trying to decide "what do I try next...or which amps should I compare"?

Hi snapsc

That question can probably be answered from a few points of view. Most of my clients I would say, have either had it with HEA or suspect there is something wrong with this HEA picture. Or have heard about me and what I do, either by reading a review or article then they get a hold of me and start their next chapter. Or their friend has converted and let them listen and borrow stuff. There actually was a time when the whole shipping issue was discussed among brands (obviously they have known about units built to ship vs units at their best state of performance). But most companies just want to make the sale and are glad they are in business. There are some designers who have tried to say they make their components that way on purpose, but these guys have been proven wrong by those of us who actually test these issues.

There is a way around some of these issues that designers can, and some do, implement. If you look inside of components many times you see ties, but you will also see some use supports for their wire runs instead of ties. A wire support lifts the wire from the chassis and doesn't put tension on the wires. On these supports is a clip where you can easily get the wire out, without having to snip anything. As far as transformers, many companies make their transformers so they can be easily loosened. There are a bunch of these tweaks (resets) you can do to the right component, and you never have to be concerned about warranty issues.

Here's the deal though. Since designers know this is "Audio" shouldn't they be making components already this way? They shouldn't be asking you to pay these outrageous prices and yet not even supply you with the opportunity to reset your component to it's original design. HEA should mean advanced, but we can all do these tests and see that we are not getting the bang for our buck.

One of the reasons so many are turning to these receivers and other products is because of the build. For example if you look inside of the Sherwood, you will see an amazing layout. The mass companies have really done their homework. One of the first comments I hear when someone goes to the Sherwood or other well done modern products is "my soundstage really opened up and is more detailed".

I think people should keep in mind too, that I have and continue to bring in a lot of high end gear so I don't make these observations without merit. I don't mention a lot of brands simply because my job is to point to the good and not put down anyone's specific brand. That's not what I'm about. However, I also feel responsible to tell the truth and the fact is HEA is no longer ahead of the curve.

Michael Green

www.michaelgreenaudio.net

cj, i do not perceive michael's very cordial posts as any form of sales pitch--he expressed an opinion and responded to a question regarding a piece of budget gear, which he doesn't even sell. one might choose not to buy into his tuning blocks or other esoterica, but he registers as a well-informed gentleman and is entitled to his views.
@ loomis

Michael has been cordial and certainly is entitled to express his views. Unfortunately, the nature of his post wasn't to talk about the subject of the thread - budget amps - but a budget receiver that was made for one year back in 2012. Bringing up budget receivers (current production or obsolete) in a budget amp thread is a classic case of sidetracking. It is also a convenient way of introducing Mike's "tweak" products which he didn't wait to talk about - mentioning it in his first post.  Sidetracking is one issue. Mixing discussion about standard (widely accepted "technology") products with "tweak" (considered by a large percentage of people to be sales hyped nothingburger) is a prescription for fireworks. In every thread, you will have skilled, knowledgeable people participating down to complete novice and everything in between. You will also have people who are purely objective down to purely subjective and everything in between with regard to how they evaluate audiophile equipment. "Tweaks", by their very nature, belong squarely in the "subjective" camp. Most of the purveyors of "tweaks" scoff at the notion of any attempt to objectively measure performance to back up or denigrate claims that are made for said products. When tweaks and their purveyors  enter thread discussions where some level of objectivity is expected, they appear to expect that "objectivists"  or those who rely on both subjective and objective criteria, should suspend all judgment or skepticism of the "unproven" claims associated with tweaks. This is an unrealistic and unfair expectation. Similarly, it is unreasonable, inappropriate, and unfair for a pure "objectivist" to barge into a thread within a "tweak sub- forum" and ridicule participants therein for their "unproven" beliefs or "audible experiences".Basically, what I'm suggesting is that there should be some "safe space" allotted for the purveyors of "tweaks" that is free from the ridicule and judgment a lot of us possess. Likewise, the "tweak faithful" should respect the rights of pure or quasi objectivists to be critical of tweak claims when participating in "non tweak" item discussions. In every case, the thread starter should have the final say as to what is appropriate and what's not in terms of relevance to the subject matter originally introduced - aside from the role that site moderation plays. In this particular case, snapsc might not care one way or the other. But I can assure you, a high percentage of people (myself included) who participate here will be turned off if a budget amp discussion sidetracks to the claimed effect of blocks of wood versus plastic feet on an aging budget receiver.  Site moderators, for whatever reason, have not seen fit to draw borders in terms of forum subsections that delineate subjectivist and objectivist subject matter. I'm sure they have their reasons. I will say, however, that if such lines were drawn, threads like the  one long time member Elizabeth recently bemoaned that featured "never ending" debate, would likely cease to exist.

Hi Loomis

Thanks, I appreciate that! Yep, my point may have been taken a little out of context by cj. Or I wasn't being clear enough. I can also see why folks would get rattled when that sales pitch line gets rolling. Sometimes it's hard to see excitement vs salesman, especially in this hobby lol.

My comment was based on this from the OP

"Until you have a chance to try a piece of equipment in your home in your system in your room, you can only speculate as to what it will sound like."

Without going overboard I was trying to say how we all have a different point of reference when we talk about our setups, and how we evaluate sound from components. My conclusions on what is good or not so good is from a certain method of listening, and I felt it important to include that.

So thanks again, I didn't want to respond to cj and come off rude.

Michael Green

www.michaelgreenaudio.net

@ snapsc

Back on track.... If used amps are a part of the mix, I would like to offer my recent experience with a Crown K2. I've read about these for years and while they are long since out of production, there are plenty that show up on Ebay (K1 and K2) for less than $500. If reliability is a concern given their age, my experience indicates that they are indeed "a Crown" in every respect. Having owned many Crowns (MA 2400 back to the DC300), I can say this one is clean, quiet, and rugged like the rest. It's "balanced current" design however is very different from anything previous and the resulting bass performance is phenomenal -something you'd expect from an amp with a damping factor of 3000. Other than that, I haven't found anything really remarkable about its sound. It is dead quiet and has a midrange and treble performance that compares favorably to anything else in Crown's current production - for what that is worth. I've also enjoyed using Perreaux amps for years - recently picked up another (PMF 3350) here on Agon at a very reasonable price. Like the Crowns, they are built like brick #### houses  - known for long term reliability. Their sound has always been pleasing to my ears despite the "mosfet mist" others have talked about.
@michaelgreenaudio.net

Thank goodness we we have you as an expert to set us straight that high end audio is mainly for chumps
+1 for A/B class Odyssey amps. I’ve tried lots of budget amps (Van Alstine, Parasound Halo, etc) and Klaus’ amps blew the others away, and run very cool. I have the Stratos, which cost me $500 second hand.
Hijacked?
Mr greens been around for a long time 'tweaking' stuff... If it works do it. If you can hear the difference than do it. Why not.

'Looking" at the Sherwood 4105 alum stamped chassis it sure appears it has many areas for improvement.. I have not heard it at all.. Looks to be a $50 used item.  Reminds me of the natural sound yamaha line which sounded good, decent 'mid' end.  I've heard realistic stuff sound darn good too, like the little 42 2101a phono preamp. However I have not ever listened to any crown amp in anything other than a pa system. I guess I missed out on when they became high end amplifiers. All the digital crap amps , no thanks.

And here we are in an opinonated market based on money, value, quality and of course what you can hear or think you can hear. I love the zedaudiocorp reads on his wesite.  Beez wax fuse, 1000$ power cables, great 'magic' happening.. Magically empting your wallet.

My experience with Class D amps is that they may be very good at control and very clean (although the older Class D circuits typically were driven by the speakers impedance curve, which could result in things like weak bass/midbass and rolled off highs).  However, I found Class D amps lacking in something – they were very clean but they just did not “sing” and lacked that emotional engagement.  I think this is primarily due to the inability to respond fast enough to the higher frequencies (which causes Class D to typically lack “air”).  I believe that the on/off switching method in Class D transistor just cannot respond fast enough to the higher frequencies to properly give it good sound quality.

That being said, I think the Crown XLS could be a very good subwoofer amp.  The Nuprime might be interesting with its tube like sound and Class A input stage.  But I’m not sure that either one will “sing” like the Parasound A23.  Though, if you have a low impedance speaker (such as a pure 4 ohm or with woofers that drop down to 3-4 ohms), the Parasound may not have the bass/sub-bass response.  If you have this situation, maybe look into the Parasound 2250v2, which has a much larger power supply, but maybe not quite the "Halo" level sound quality.  I think 2250 is still very good, though.

The Odyssey amps mentioned here are also excellent.  I think they have very excellent resolution and sound quality.  However, Klaus likes to use smaller transformers (400VA for all his amps).  The more expensive Stratos has an option for dual transformers (2 x 400VA), but they are still on the small side.  Other options include increased capacitor bank, which is excellent.  I think the end result will be very tight bass, but not the full sub-bass experience that a larger transformer would give you.  The Parasound 2250 will likely have more brute force for a deeper sub-bass response, but it will not have the resolution of the Odyssey.  Even the Parasound A23 with its 1000VA transformer may be better.

fwiw, i picked up the sherwood 4105 receiver touted by michaelgreen ($19.99 on ebay) and it is a good sounding piece--impressively transparent, with good low end control and little of the brittle "digital" quality of typical low end ss gear.
any schematics available to swap out parts , replace some caps with poly if they fit? how many opamps are in the thing? crappy electrolytics caps in a signal path? replace any cheap ’aluminum’ or other crappy wire in the signal path, crap binding posts? the entire chassis looks like it could use some sound damening or some kind of anti vibration mat stuck to some of the solid areas that are not vented. rubber grommet the power tranny unlkess it need to be grounded..  lets do some mr green tweaks and hear it...
One of the "intents" of this thread was to reinforce an idea that is woven throughout hundreds of forum threads/comments:  that you can enter/enjoy this hobby without spending a fortune...that "budget" equipment can sound pretty darn good....and that there are enough differences in sound to make it worth a person investigating what might suit them the best.

My hope was that people would add their own experiences with these three amps...and put forward additional budget amps/receivers that they think also sound good at a budget price and therefore worth discussing and considering....in other words, more points of entry or possible upgrades for consideration.

As for budget tweaks to budget new or preowned equipment, I suspect that it is unlikely that new people entering the hobby will want to go this route and more likely that they will want to just straight up buy a budget product that has been well reviewed....maybe a new thread is in order; "budget tweaks resulting in better sounding budget equipment".