Unfortunately, not only do they not say "all amplifiers sound the same," they point out many of the measurable differences that lead to demonstrable audible differences. So a good example of how perfectly reasonable views are being misrepresented.
That beast does indeed appear to be mythical.
No, sorry. The only thing that came to mind when you said 4558 was the classic "Screamer" effect pedal. It's supposed to have a tube overdrive sound.
I couldn't figure out why you would use one of those!
You must be using the RC4558 op amp, right?
(note to self: Google first, think later)
I did experiments. Changed opamps in different strips, then compared them. Original JRC opamps biased to class A won. Not because of tube overdrive, because of minimum of "opamp-specific underdrive". The test, very convincing one, is to whisper to the nice microphone, slowly backing up. Bad opamps cause from some distance more abrupt change of loudness, and even added harshness.
Very good thoughts, indeed! And very valid. Of course, looking at the topology of some other amp you may decide that this particular test is meaningless. Each topology fixing one illnesses cause other illnesses, so no single set of tests are possible for different topologies.
My Denon AVR-591 in living room (completely unopened, never modified!) can put in shame many so called high-end products.
I remember many years ago, when I was a computer programmer, learning about black box and white box testing. Black box testing just compares outputs with expected outputs, but does not enquire about what is going on inside the box. White box testing deliberately sets out to explore and break the internal mechanisms of the box. We need both for amplifiers. So far, we have mainly been talking about black box testing.
No, I was mainly talking about stress-testing of components, parameters, and different design approaches of white - boxes that lead to better black-box listening.
Easy John, wrong target , Preaching to the choir .........
So Bipolar is better here ...?
How does one determine the "right " rectifier and how does the wrong "rectifier " affects the sound...?
Many ....... I highly doubt that Wave .....
Totally agreed, this is my line of thinking as well. Aside from the normal stuff about type of harmonics and order, that makes one THD reading different from another, even though they are the same "number".
Let me expand - in electronics EMI testing, they have a test called "susceptibility". Normally, you'd think with EMI you're concerned about what a device emits. This test tells you if the device is susceptible to EMI interference, both radiated through the air, and conducted (through the power line).
With audio gear, in most cases equipment is tested in a lab, under "controlled conditions", more or less. I think in audio we need more susceptibility testing under real world conditions - i.e. how does variations in non-controlled environmental factors affect the measurements?
I think to better quantify it, it needs testing under conditions seen in actual home installations. With dirty power, leading and lagging power factor on the mains, for instance. With cells phones, wifi, dimmers, locally energized and working.
It should be qualified at full acoustic volume, in a position normally seen - between both speakers, against the back wall. I mention this, as it is normally a high pressure zone, and acoustic levels here will be much higher than at the listener's chair. Are components inside audio gear susceptible to to high acoustic levels? Do the engineers ever test that? Tubes certainly are.
How about source and line level components - people are aware phono cartridges need proper controlled loading. When was the last time you saw any line level component tested at loads of say 1k, 5k, 10k, 50k? Does anyone think it may sound different with a 1K load versus 50K? Many components DO measure differently in that example. Who uses a 1K load? I see people selling these passive preamp things that load the source at 1K and supposedly folks love them.
And then there is cable, and all the variations they can introduce, especially when you put it all together in a system. Who ever measures the "system" end to end for flatness, distortion, transient response, etc?
No one does, as we want "controlled" testing.
But that's what we listen to.
Many ....... I highly doubt that Wave .....
You are welcome to try for yourself. I myself was surprised.
Here is what Peter Aczel says on page 10 -
“In controlled double blind listening tests, no one has ever (yes ever!) heard a difference between two amplifiers with high input impedance, low output impedance, flat response, low distortion, and low noise, when operated at precisely matched levels (+- .1dB) and not clipped.”
So apologies that this statement, with disclaimers attached, and similar ones by others gets distilled into the short form known as “all amplifiers sound the same”. Usually, at least in my mind, the short form is meant to reference the well known long form as quoted by Peter above and others.
How so? I mean in what ways?
- Price point?
- Functionality?
- Looks?
- Power to Weight ratio?
- THD? IMD?
- Frequency Response?
- Transparency?
- Imaging? Soundstage?
- Detail?
- Tonal Balance?
You talking Toobs or sand ...?
Err, what is whitebox, blackbox testing ....... ?
The same:
that it offers for a fraction of price.
No doubts it measures well, but I did not do that. I bought it as a donor for it's Audissey DSP, but still use as-is, more than year...
I have woofers in concrete boxes and subwoofer under floor, concrete horn, driven by another amps, though...
Front speakers are line arrays in wall around screen, rear speakers are 6.5" coaxials.
Output stages are very simple: pair of LTP stages well balanced in terms of currents, with current mirror in the second one, and Sanken fast Darlingtons. Smart frequency compensation. Current limited by simple Zeners. Almost Nelson Pass style, simple like Kalashnikov machinegun.
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