Yes. I think it is measured at 0dB (max output) calibrated according to manufacturer specs.
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Amplifiers can you hear a diffrence?
- Thread starter Pjetrof
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Yes. I think it is measured at 0dB (max output) calibrated according to manufacturer specs.
Blumlein 88
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I don't know most noise output voltage I've seen is at idle.
Like my amps are said at idle to be less than 125 microvolts. Which could also be called less than -78 dbV.
Dynamic range is specced at 111db which if you use the 45 volts rated output (33 dbV) with the idle noise (-78 dbV) it all adds up to dynamic range of 111 db.
Like my amps are said at idle to be less than 125 microvolts. Which could also be called less than -78 dbV.
Dynamic range is specced at 111db which if you use the 45 volts rated output (33 dbV) with the idle noise (-78 dbV) it all adds up to dynamic range of 111 db.
What I have found to make amps sound different is lack of power and high output impedance.
High output impedance alters the frequency response of the speakers, and we are very sensitive to frequency response.
Not enough power is obvious.
We don't want audible noise but I haven't had an amp with noise levels high enough to be annoying in 50 years.
I would expect a lot of transformer coupled amps to have quite a lot of distortion products from the bass in the mid range, but whether this is audible or not i haven't tried to ascertain.
My amp choice has calmed down over the years and now the thing I like most about my current amp is the rotary volume control on the remote. I hate up/down buttons.
High output impedance alters the frequency response of the speakers, and we are very sensitive to frequency response.
Not enough power is obvious.
We don't want audible noise but I haven't had an amp with noise levels high enough to be annoying in 50 years.
I would expect a lot of transformer coupled amps to have quite a lot of distortion products from the bass in the mid range, but whether this is audible or not i haven't tried to ascertain.
My amp choice has calmed down over the years and now the thing I like most about my current amp is the rotary volume control on the remote. I hate up/down buttons.
One can easily detect 0.3% THD and -70dB crosstalk... if it comes from an amp chip like the inglorious TDA8950 (a pretty broken PWM design).... why? Because it is tons of higher harmonics only with a non-stable spectrum vs power... piano decay sound like digeridoo...
Accumulated numbers don't tell any significant story.
I think it's measured at 0dB to check for hiss.
Some of us are simply trying to construct the cleanest possible signal path for the elimination of doubts (and to minimize upgrade desires) within our own personal parameters and predilections.
Well, I hope you do that when you already have extremely good speakers (i.e. with distorsion measurements available).
IMO, throwing money on swapping modern electronic components in your signal chain just to improve specs is a waste of money. If you want to improve SQ the only right thing to do is to upgrade your speakers as they are by far the only component where specs really matter.
caioferrari
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I made some tests with my amps. A Yamaha A-S501 vs Crown XLS 1502 with a pair of Klipsch RB51II and a Marantz CD5005 as a source. I couldn't hear a difference between those two. I did another comparison between the Yamaha and a Brazilian power amp with 35wpc from the 80s. In this case I could hear a difference at high frequency: the older power amp didn't respond to higher frequencies as good as Yamaha. Seems to be a roll of before the 20Khz
When I say my experience at some foruns, people call me crazy, that obviously the Yamaha sounds better than Crown because the last one is a pro amp and doesn't have a good quality for Hifi. The most of times they say that my cables are not good enough to show the differences between the two amps.
I don't know guys, may be my ears are broken or those people are getting nuts.
When I say my experience at some foruns, people call me crazy, that obviously the Yamaha sounds better than Crown because the last one is a pro amp and doesn't have a good quality for Hifi. The most of times they say that my cables are not good enough to show the differences between the two amps.
I don't know guys, may be my ears are broken or those people are getting nuts.
You can guess what's our take. This kind of audiophile is by definition neurotic, or even psychotic, for those who "really hear something".
Nobody claims all amps sound the same, there is always the qualification at least that they both have to be operating under clipping level.
Richard Clark had the famous $10k challenge for anyone that could distinguish between two amps in blind ABX testing. (As far as I know, prize was never claimed, and he ran a lot of tests).
His caveats:
Amps had to be competently designed and in good working order.
The level had to be exactly matched
Frequency response had to be the same, if not he would EQ with a filter to match
Amps operated below their clipping power level
Speakers had to be regular dynamic drivers, not panel designs.
Within these constraints, users could bring any amps and speakers they desired to take his challenge test.
This is all quite sensible for this kind of test. He also never claimed all amps were the same. Just that for a given power level, things like price, features, esthetics, reliability should be the determining criteria when purchasing an amp.
The interesting thing is that his tests proved what he did not believe, and many people still don’t, was true.
The test run in this article is not that interesting, outside that it demonstrates amps have different clipping characteristics, that are audible to some degree.
What is interesting is that Benchmark has this whole “first watt” theory, that performance at low output levels is critical for superior audio performance.
On their site they have a discussion of this theory, and the results of an ABX test they claim easily showed that their AHB2 was distinguished from a decent competitor at a low power level.
However, they only disclose that this test was passed with a test tone! I would presume they attempted the same test with music. Since they don’t mention it, I infer that their amp was not distinguished from the competition in ABX listening tests with music.
If this is the case, they refute their own argument!
Weird.
https://benchmarkmedia.com/blogs/application_notes/power-amplifiers-the-importance-of-the-first-watt
tecnogadget
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That makes for a great set of parameters! I don't know why some people in other forums love to trash the THX Ultra certifications as just a simple kind of sticker the manufacture pays for. At the end of the day, lots of AVR's that measure great have this certification.
Trashing example: "Most, if not all, AVRs made today far exceed THX standards. (and have for some years). THX certification is outdated and certainly doesn't warrant the hefty license fee. "
I'd like to think the hate is towards the fact that other great amps/AVR that also measure great without the certification.
Onkyo TX-SR805 is a nice AVR to test since its quite inexpensive (circa 2007) and is THX Ultra 2.
Another legacy AVR's that were expensive at their time but now have become cheap are Yamaha Z9 and Z11, both THX Ultra 2 but heavy as hell.
FireLion
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I currently have a Matrix Audio HPA-3B and 789. They are very close but the Matrix has slightly more punch in the bass and the mid range has more body. It's marginal but noticable ABX'ing them from the same DAC. The difference being is one is class A and the other is A/B.
I actually prefer the Matrix a little but love the 789 too. It's also worth noting I do have opa1656's in the Matrix and it already had two sparkos voltage regulators. I'm not sure what they do but supposedly the opa1656 has low distortion numbers and was recommended by a TI engineer.
Another thing I just noticed was the 789 is 6 watts @ 32 ohms and the matrix is 3.8 but at 300 and 600 ohms the matrix has double the power and then some.
I actually prefer the Matrix a little but love the 789 too. It's also worth noting I do have opa1656's in the Matrix and it already had two sparkos voltage regulators. I'm not sure what they do but supposedly the opa1656 has low distortion numbers and was recommended by a TI engineer.
Another thing I just noticed was the 789 is 6 watts @ 32 ohms and the matrix is 3.8 but at 300 and 600 ohms the matrix has double the power and then some.
Blumlein 88
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Richard Clark performed his test over 500 times with no winners. He stopped doing it after that.
Blumlein 88
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Did you match levels carefully in these tests? Not by ear either, but with a meter.
OP
Pjetrof
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There are several important differences between these two amplifiers that can change the way the low frequencies are reproduced. The Accuphase response is -3 dB at 5 Hz while the AHB2 extends all the way down to 0.1 Hz (-3 dB). The effect of this is that Accuphase delivers frequencies near 20 Hz slightly late (due to the low-frequency phase response errors which are a direct result 5 Hz lower limit of the Accuphase amplifier). A second issue is that the damping factor is much higher in the AHB2. The Accuphase cannot damp the drivers as quickly. The third issue is that the Accuphase may have output current limitations that are contributing additional distortions. In contrast, the AHB2 output stage is drawing current from tightly regulated power supply rails and there is no current limiting circuit in series with the output stage. The output current of the AHB2 is only limited by an overload protection system that measures the output current and then shuts the amplifier down is an unsafe load (or short circuit) is causing excessive output current. Until this shutdown threshold is reached, there is no limit to the output current delivered by the AHB2. Before this threshold is reached, the high-current warning lights will flash, but this is not an indication that current is being limited, it is just a warning that you are near the shut-down threshold.
How does this answer from an other thread, relate to my question?
How does this answer from an other thread, relate to my question?
Hi Pjetrof,
The biggest factor in the difference between amplifiers, in my opinion, is the listener.
There are a million little nuances in our physical and emotional states that make us perceive objectively equal situations differently, and that goes for hearing as much as any other sense.
The ability to distinguish between, for example, THDs of amps is virtually non-existent for human ears.
So is the ability to feel exactly the same now as at any other point in time, and I think that's where perception makes the difference (not technical specs).
At ASR I see peope trying to let the science of audio guide their knowledge, knowing that all human perception is, by nature, not fact, consistent or measurable.
That doesn't devaluate the emotional benefit of someone "loving their amp" though. That "happy state" can massively contribute to their listening experience.
The biggest factor in the difference between amplifiers, in my opinion, is the listener.
There are a million little nuances in our physical and emotional states that make us perceive objectively equal situations differently, and that goes for hearing as much as any other sense.
The ability to distinguish between, for example, THDs of amps is virtually non-existent for human ears.
So is the ability to feel exactly the same now as at any other point in time, and I think that's where perception makes the difference (not technical specs).
At ASR I see peope trying to let the science of audio guide their knowledge, knowing that all human perception is, by nature, not fact, consistent or measurable.
That doesn't devaluate the emotional benefit of someone "loving their amp" though. That "happy state" can massively contribute to their listening experience.
So, we shouldn't let science 'guide' our knowledge?
You misunderstand me I'm afraid. The science is exactly what's important, it explains why the subjective listener makes the difference, not the gear.
That doesn't mean that, in the end, the listener needs to be satisfied with his gear choices, regardless of wether that's because he loves the science or his subjective perception.
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