If you wonder if capacitors sound different, build a two way and experiment for yourself.
But all you will know is they sound different in that configuration along with the rest of the system and the room.
Nothing can be evaluated in exclusio.
Flaws in one system may be ameliorated by defects in another. Grunge monsters may prefer a completely different set of flaws to an opera lover.
While both are excellent, swapped, the Class D woofer amp and tube mid range are pretty unlistenable. Either full range into a different loudspeaker are PDG!
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UBoob compresses audio.
UTTER waste of time!
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Voltage from a tube amplifier OPT will vary considerably depending on the speaker impedance at the test frequency.
The ENTIRE UBoob demo idea is nonsense from the git-go
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This statement is incorrect. This amp uses about 15 dB of feedback, allowing it to behave as a voltage source with most speakers.
Most Speakers vary immensely. 😉
To date, I've yet to see a tube amp measurement that does not look similar to the Black Line into the Stereophile simulated speaker load. Many speakers' impedance curves make the Simulated load look like a resistor.
"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
The only measurement that matters is how it sounds in your system in your room with your program. Evaluation by any other method is foolish unless you are buying HiFi Jewelry or Furniture.
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BTW, my videos were all made using a Nikon D750 SLR.
😴😴😴😴😴😴😴
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Ended on the opening post...
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Have you looked?
For decades...
Most tube amp manufacturers these days seem to eschew lots of feedback.
FWIW, I've never measured a tube amp output voltage into a loudspeaker that was anywhere close to what an SS amp delivered into the same load... going back to the 70's. Admittedly, it's a small sample, and largely irrelevant as measurements mostly don't mean diddly. 😎
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Music is a sequence of fundamentals rich in harmonics. The ear brain can definitely tell when the harmonics are shifted.
OTL - Output TransformerLESS - is off topic. The images are for "tube amplifier output transformer". Let’s take it as written that atmasphere makes fine amps.
The question was about current and voltage. The current and voltage cannot be the same if the harmonics are temporally shifted relative to the fundamental.
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Maybe I am simple fellow… but how can the sound (SPL) be the same, if the current (and voltage) are not the same?
There’s much more to sound than SPL.
Mostly, the measurements quoted in HiFi are THD and IM @ a power level.
Occasionally, a square wave or distortion spectra.
ALL into a resistor, not a dynamic loudspeaker load.
This series of frequencies into an 8Ω load resistor gives an idea of the Phase Shift in a tube amplifier output transformer @ 10W RMS. The ear is extremely sensitive to phase, but hardly anyone mentions it. Ideally all lines should look like 200Hz & 2kHz as 45° lines. Nobody publishes anything other simple meaningless measurements that the untrained can lap up.
20Hz.jpg (566×477) (ielogical.com)
200Hz.jpg (566×477) (ielogical.com)
2kHz.jpg (566×477) (ielogical.com)
20kHz.jpg (566×477) (ielogical.com)
200kHz.jpg (566×477) (ielogical.com)
A solid state amp would do much better.
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@holmz
If a single frequency SPL is measured with the same terminal voltage, that SPL should be the same for any amp.
Since almost agree that tubes sound different than solid state, then what makes up the ’voltage’ must vary. So if you measure 1kHz 2.83v at the speaker, an SS amp could be 99.999% 1kHz. A tube amp may be 99.5% 1kHz, 0.25% 2kHz, 0.05% 3kHz, etc. Additionally, depending on the amp and system, there could be PSU or loop components. An FFT of the captured output could be revealing.
There fore, depending on the equipment and pertaining to the suggestion to measure the terminal voltage to match levels, is that the program SPL may not be the same with the same measured voltage assumed to be made at a reference frequency.
Since the early 70’s I’ve had time coherent speakers: Dalhquist DQ-10, KEF 105 MkII, BiAmp Magnepan Tympany IV. From 1987 to 2020, I used Spica TC-50, which were the speakers I carried around to studios. The TC-50 was the first box speaker I heard that more correctly presented the phase coherence that I first heard on Quad 57s. and were able to correctly produce what I heard on time corrected BIG monitors in recording studios. I bought the TC-50 without asking the price or knowing anything about them as they were the first small monitor I’d heard that came close to presenting the recorded sound field. Since 2020, I’ve used Eminent Tech LFT8b’s, triamped with time alignment via miniDSP. The speakers can produce a tolerable facsimile of a square wave. And then I screw it up with tubes.
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The difference you hear isn't on account of power!
Yes it is.
It's not that the distortion signature is too small, it's that no one measures it. No SPL meter is going to be better than ±0.1db @ 85dB. It likely has a nonlinear response. In absolute terms, it's not even close.
Back in the 80's Bob Carver tweaked an amp to sound exactly like another: The Carver Challenge | Stereophile.com
FWIW, we gave up on matched level listening tests in the 70's simply because it's about as worthless reading the spec sheet. An amplifier is but one component in a system. Change one thing, change everything. I think it's stood me in good stead when a guitarist says "Joe Pass is sitting RIGHT THERE!"
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"The Final Achievement
After this last bit of tweaking, where Bob was able to reinstate his 70dB null while driving a very difficult load, we now had what sounded like two absolutely identical amplifiers." [emphasis added]
If one amp was making more higher ordered harmonics, it likely would have sounded louder. An SPL meter gets to the bottom of that pretty quickly.
¿Que? Loudness? Never mentioned it. We were matching level w SPL meter @ 1Khz and Pink Noise and also measuring amplifier voltage output w AC voltmeter. Some amplifiers were sonically very close and some not. Some better with one speaker and others with another. In the end, we came to the conclusion that synergy exists and it's not predictable.
Spec sheets report measurements, or at least some do. 😉
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And I further disagree as I have the NIOSH app on my iPad
No mention of calibrated microphone or calibration standard. Both are necessary.
I trust Bob Carver about as much as a preacher.
Carver made the claim, the Doubting Thomases verified he did what he said he could.
I have heard only good things about Ralph
AFAIR, I've only ever said nice things about Ralph and atmasphere. He's a smart guy and his products are very good.
While amp circuits may lead to very similar outcomes there are vast differences in power supplies.
Spot on. Many designers don't understand that the amplifier circuitry is a power supply regulator. If the PSU dynamic response is bad, then that will manifest itself in the output.
The problem has been that the semiconductors needed to really supplant tubes (meaning: to make a solid state amp that isn't harsh) didn't exist in the 1970s or 1980s.
V-FETs. Sony and Yamaha made some gorgeous sounding amplifiers that cost a fortune. AND plenty of good ideas that advanced the SOTA. And there are plenty of audio products currently manufactured that make one shake one's head and wonder "What were they thinking?"
This has been what has kept tube amplifiers in business the last 70 years since they do offer a way around this issue (they make enough lower ordered harmonics to mask the harshness of the higher orders they also make).
Harmonics, phase response, transient response, compression, dynamic noise spectra, damping factor, glowing sexy glass bottles, emotional involvement adjusting bias, tube rolling, ad infinitum...
IMO we've only just arrived near the top of the R&D sigmoid curve in audio in the last ten years or so.
If we are near the top, are we about to start a slide down in a short while as Handy suggests? From my perspective, apart from the bling factor which is lamentably far to prevalent, audio improvement proceeds apace.
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And Bias drift...
Bottleheads are sensitive to bias, some too much so and just wear out the trim pots.
SS amps often come misbiased and likely never get rebiased.
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Another seldom checked SS / tube difference is DC offset. A tube amp w OPT has none and an SS amp likely has some. DC is a voice coil heater. When voice coils heat, their resistance changes. Resistance changes cause corner frequency changes with passive crossovers.
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Carver is an innovator with decades long history of accomplishments. And, yes, a bit of a showman.
I'll take than any day over bling purveyors @ Synergistic Research, AudioQuest, REL, et al.
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How were the systems measured?
Spectrum?
Program?
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"However there was a dramatic change around 1970 when Sound Technology appeared on the scene.
...
The 1000A was quickly followed by the model 1700A which was a state of the art audio measuring system which could read distortion (THD) down to 0.001%"
from Sound Technology Test Equipment
ST 1700A was introduced in 1971 and thus made with late 1960’s level technology.
IMO, the biggest improvements have come from capacitors, resistor precision and less costly, higher quality drivers which let the music through. Solid state devices, like tubes, so far exceed audio frequency requirements as to be nearly irrelevant.
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Distortion is measured statically.
Music isn't.
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@phd
I thought "a straight wire with gain" is unachievable currently but would be the most desirable scenario for ultimately the best possible sound.
From the musician onward through the instrument, studio or venue, microphone, cables, pre-amp, mixing desk, recorder... everything adds coloration.
Some only listen to chamber music, others acid rock, so their preferred distortions are widely divergent. Neither would likely prefer a SWwG system over their flawed but cherished one.
Oh, and btw, Masters make about 50% more than PhDs. 😏
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