what's going on with specs?

Hello,
Call PS Audio and ask. That’s a great question. If you get a response please post. 

The no brainer answer to a amp is AGD Audion.
Search the Forum threads for AGD. You will find that every owner says about the same thing: the best amps regardless of price.
The Audions are $7.5K but IME I have never heard any amp in 50 years at this. They have the musicality of a great SET and the detail of a great SS. I won’t go on and on but I clearly decided to buy mine after reading all the user posts on the Forum. The comments are not the usual raves.

Preference of sound is not the point. Whether one thinks certain products that reproduce music or if a live event sounds "good" is subjective. If one thinks amp A sounds better than amp B buy amp A but If an amplifiers noise and distortion are measured to be beyond human hearing then that component is considered neutral or transparent, it neither adds or subtracts from the signal sent. If 2 amplifiers measure the same and are considered transparent then they will sound the same or so close they can't be differentiated in a blind test. The test can be one day or 2 days or 10 days, months apart. If one can successfully pick one over the other better than chance no matter how many times they listen then the amps either don't measure the same or the test is flawed. 

The biggest variable in the determination of how good something sounds when listening to reproduced or actual live music is the human auditory system. Thus, it is not true that 2 amplifiers that measure the same will sound identical, even if they are listened to at different times by the same human. This fallacy is sometimes repeated by engineers but never would never be uttered by a neuroscientist who understands the complexity of the human auditory system.

so close you would have a hard time telling them apart better than guessing

Perhaps some might be guessing, but there are innumerable people who can tell the difference on any program.

In firearms, there a units whose accuracy is so good that they are set aside for competition. These arms may be designated 1:100 or 1:1000 depending on their superiority.

The same is true for many manufactured item: Engines, binoculars, electronics, etc. Manufacturers run Monte Carlo analysis based on component part tolerances. Just as there are 1:100 on the top, there will be the same on the bottom. They meet spec, but will never hold.

I once bought an amp a pal owned based on how it sounded in both our systems. After a couple of weeks, I returned the one I bought as it was sonically inferior. On the bench, both measured the same.

When we shipped systems for recording studios, the final QC was a listening test. Some units were reworked, some binned.

Of the 4 amps the OP mentions maybe and that's a long shot maybe one might pick out the BHK 250 over the other 3 between the other 3 I know I wouldn't be able too.

Signal over noise and distortion. Power v distortion full load at 4 Ohm both channels driven. Frequency response. Get 2 amps that measure about the same driven below clipping will sound the same or at least so close you would have a hard time telling them apart better than guessing. As long as the amp is considered neutral or transparent with a SINAD in the middle 90's up good luck picking which is which in a blind test.

2 amps that measure the same as long as they are used within their limits will sound the same

Please list the required measurements

Measurements change with temperature, so unless the amp is played at the measurement temperature, they are meaningless.

Measurements are made with static signals, so unless you listen to test tones, they are meaningless.

Music is art, music reproduction is 100% science. 2 amps that measure the same as long as they are used within their limits will sound the same. 

@mrklas, ha! Perhaps?

To each their own, but I think trying to apply a measurement methodology to musical reproduction is a fruitless endeavor. Music is art. We should be buying what sounds good to ourselves. However, I do understand the DTC model is driving the use of audio measurements in an attempt to determine what sounds good. It’s a sad state of affairs. 

@unsound are we in violent agreement?

Once you get beyond ample current flow for a given speaker load, and reasonable output power for a desired volume level, specs have seriously limited value in high end audio. As soon as manufacturers figured out how to build circuits that measured well according to spec rules, they pretty much became moot point....which was decades ago. Specs may have actually been detrimental to sound quality at some point, because good specs became more critical than good sound. Amplifier specs tell you nearly as much about sound quality as dimensions tell you about how comfortable a sofa is.

Below is a list of sonic attributes that are accurately described by specs: ;-)

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Take a look at the excellent Coda Amplifier, or integrated amp .
it has 3 powers to choose from Same price ,for example the lowesr power has the highest amount of 1st watts into pure     class-A . 18 1st watts in pure class A , 150wpc ,300, 600 wpc
250,500,, power supplies count , a sealed potted ,not open toroidal transformers,and Huge 3000,va ,and over 80k in capacitance, 120 short term amps on demand , no other amp comes close to this and a very good deal under $5500Mike at Audio Archon
will give you a good deal and very natural sounding 
10 year warranty, 5 year transferrable ,check it out .

@dconfalone

There is some reason a Boulder amp is going to sound better than a Sony receiver and it must show in some measurements.

You are mistaken, our audio acuity is much more complex than current science can measure. 2 amps that measure the same but are designed differently will sound different. Also, our individual audio preferences are different.  

The best way to evaluate a component is to demo it in one’s own system. If you cannot, then you research reviews of the component while taking into account the rest of the audio chain. Component to another component comparisons gives you an idea on which is the best price/performance. After that it’s just a best guess what you’ll like- then roll the dice. Hope I didn’t miss any steps.

If you buy used, you can sell it and not lose much $ provided that the component is marketable (enough demand).

Bryston is a brand worthy of your shortlist. 20 year warranty to boot. 

It’s like the internet is a new technology for most of you. Youtube -> enter name of amp -> watch vidya

I have a JC5 running some Revel F208s and it sounds amazing. My buddy has a BHK 250 running some Sonus Faber Olympica Nova V's and it also sounds amazing. You need to figure out what you want. Both amps are different variations of awesome.

If you’re discussing Watts, the room size, its acoustic liveness, and most importantly YOU and your musical choices and volume demands all matter in determining how much amp you want. SS amps generally have low output impedance and ones on your list have high current, so the 3.4 Ohm minimum of your speakers will not faze any of them nor cause major tonal surprises.
Even a Naim 80 W amp can deliver incredibly dynamic music reproduction. People love the Pass Labs 25 W amp. If you’re looking for nightclub volume you need all you can get…and bigger speakers. 

You can also put the Anthem P2 power amp onto your list if you want and priced with the rest of your list around 4.5K

@mrklas, specs don’t matter until they do,

I confident that in some situations that vey same amp won’t perform as well as many amplifiers rated much higher.
And the specs sure come in handy for such considerations.

@unsound specs matter until they don't

Audio research has stereo watt amplifiers rated at 75-85 watts that can deliver sound quality, quality and dynamics comparable to may amplifiers rated much higher.    

Go with a parasound halo. You wont be disappointed. And you can send me the difference of about 2000 from the minimum side of your budget. Lol very nice amps well designed and and well regarded by those in the audiophiliac circles. 

^Don’t confuse gain with power.


The devil is in the details. It’s important to compare apples to apples. Specs are presented as an equation; change variable / change application. Specs can offer tremendous insight into correlations, and be invaluable towards eliminating the irrelevant. Specs quantify the specifics. Specs allow for pertinent short lists. Without specs we don’t have quality and/or consistency.

Specs don’t assess the gestalt.

Specs are interesting.

I heard two stereo amps from different with different wattage ratings - one 450 watts  per channel and the other 250 watts per channel.

Conducting a listening test and using my iPhone to keep the volume at 80db there was two surprises
1. I expected the larger wattage am to have more dynamic impact - it didn't
2.  The volume number on the preamp was about 10 units higher on the 450 watt amp (in comparison to the 250 watt amp).

The good news is then the only thing that matters is how it sounds (and I guess the price might matter).

People who post this question don't consider that specs are into a resistor.

Relation to a speaker [cables included] load: LESS THAN ZERO.

ONLY SONICS MATTER. And for once I agree w MC.

"If it measures good and sounds bad, –– it is bad. If it sounds good and measures bad, –– you've measured the wrong thing." –– Daniel R. von Recklinghausen, HHScott

Specs are a very small piece of the puzzle. Your ears will give you definitive measurements.  They have a direct link to the brain. 

Measurebator, a classic from Chuck I won’t soon forget

Nor will a certain triggered prude who can’t take a joke.
Probably reminds him a little too much of himself.    
   https://youtu.be/8QOQEYA9YJo?t=8

Power and distortion specs are just a minor reference point. A 30wpc amp isn't going to have the same power as a 250wpc amp but that is about as much information you can get out of a spec sheet. A watt is a watt but some watts are more equal than others. The only way to tell is to plug one into your system and try it.

Full disclosure, much as I would love it to have been mine I must credit uber photography guru Ken Rockwell for coming (ahem) up with measurebator.   

But that doesn't mean they mean nothing right? There is some reason a Boulder amp is going to sound better than a Sony receiver and it must show in some measurements. Those are the three I'm looking at and was wondering if anyone had any experience with them or should flip a coin. 

No, they really do mean nothing. Just because I'm good and funny doesn't mean I'm also not good and serious. You really do need to figure out what kind of audiophile you are, and what you want. Right now it seems you are a measurebator and if so fine you will find the web chock full of specs you can download and get off on. If you want music though they trust me, you can very safely totally ignore all specs and do just fine.   

Seriously. Ignore all specs. Do just fine. Pay attention to listener evaluations. IF you want to listen to music. If you want to measurebate, flip a coin. Or throw a dart. Who cares? Either way you will have some meaningless measurements to get off on.

Measurebator, a classic from Chuck I won’t soon forget

It looks like the BHK 250 has more distortion 20 - 20 k than the Parasound whether it's audible  I have no idea. Of the 4 you mention paired with the Elac I doubt you could hear a difference, the BHK perhaps since it has tubes tossed in probably why it has more distortion. 

Now you've done it miller. Equated being an audiophile with religion. and that's anathema. Get it? Ha ah. No doubt that say the JC5, BHK 250, Bryston 4BCubed will all sound great. All priced near each other and listening to them at different stores will not help. This may be wrong but it seems to me the more expensive amps $20,000 and up all seem to double power from 8 to 4 ohms. Other measurements could go either way like distortion on less expensive amps can show better than more expensive ones so i agree specs are not everything. But that doesn't mean they mean nothing right? There is some reason a Boulder amp is going to sound better than a Sony receiver and it must show in some measurements. Those are the three I'm looking at and was wondering if anyone had any experience with them or should flip a coin. Oh and the Anthem STR is another contender in that price range. Any knowledge would be appreciated. 

Pay attention to what many do not publish.
Current & Capacitance?  Sometimes you have to call. Not sure what you mean by strong but if you want resiliance during demanding transients then capacitance is your friend. Also, the actual details of the power supply(VA). Numbers matter, but only a little bit. Watts rarely are the tale of the tape. 

Paul writes a daily blog / email - ask him. He is BTW an engineer w good ears. He does respond to inquiry.

The First Audiophile Commandment is Know Thyself. What you need to know is, are you an audiophile? Or a measurebator? Audiophiles love the way music sounds. Measurebators love the way numbers look.   

Figure this one out and everything else falls right into place.

Welcome to the world of audio specmanship.

Find some magazine reviews of units you're interested in; certain mags in the U.S. and Europe test the amps and publish results, so you can actually compare apples with apples.