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发表于 2019-7-11 16:56:15
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https://www.audiostream.com/content/problem-loudspeakers-page-2
Stereophile 和Audiostream的编辑 Herb Reichert :
After studying headphones for a year, I began to think that the headphone amps I was using were the weak link: that they were limiting headphone dynamics, vividness, and transparency. I wondered about the issues I alluded to above. I began to ask the designers of the best headphones what amps they used to evaluate their creations. To my surprise, several were using low-powered single-ended directly heated triode amps. To my greater surprise, the amps they said they were using were just regular loudspeaker amplifiers; with no special provisions for protecting delicate headphone diaphragms. Naturally, I was forced to make up a set of balanced-to-banana headphone cables and connect my JPS Labs Abyss AB-1266 Phi headphones directly to the output jacks of my First Watt J2. And WOW!
That was it folks.
That was the moment I first experienced the complete full potential of two-channel audio. Every audio experience before that fell into the category of a messy constricted boom-box thing. This was the moment I realized I needed a whole new vocabulary to describe what I was experiencing. Reproduction was clear and vivid beyond words.
The first words that jumped into my head were: direct, explicit, descriptive, un-impeded, immediate, essence, true, graspable, and some new word that means more transparent than the old word transparent.
I played Todd Garfinkle’s spaced-omni two microphone pure DSD2x recording of Puente Celeste’s Nama (M-A recordings MA030) through a Holo Audio Spring Level 3 Katsune Edition DAC feeding a line-level input of the Pass Labs HPA-1 headphone amp/line-level preamplifier driving the 25W First Watt J2.
With this setup, it was easy to compare the output of the J2 power amplifier to the output of the headphone jack on the HPA-1 headphone amplifier that proceeded the J2 in the audio chain. But surprisingly, there was no comparison; and I have still not recovered from how the output of the basic power amplifier could be so much more intense and real. When I closed my eyes, the performers and their instruments occupied an utterly life-like three-dimensional space with a reach out and touch it crystalline presence. I had never experienced anything like this.
I was so excited I called my headphone buddy Steve Guttenberg and literally screamed into the phone, “I found it! The Holy Grail/the Dead Sea Scrolls/the Secret of the Pyramids… of Two-Channel Audio!” The next day, I brought him my DIY cables and we tried it together. It was so amazing we both laughed.
Over the weeks and months that followed, I connected the Abyss AB-1266 Phi, the Audeze LCD-4, and the HiFiMan Susvara headphones to a variety of basic tube and solid-state power amplifiers including the Line Magnetic LM-518, the Pass Labs XA25, and the PrimaLuna Prologue Premium. The only “headphone amp” that equaled any of these amplifiers was HiFiMan’s own $15,000 USD EF-1000; which outputs 20 watts class-A (with high gain and high voltage) into a 35-ohm headphone load.
The easy, obvious answer as to why these three world-class headphones sounded more real and transparent than any audio reproduction I’ve known is: these basic power amplifier’s connected via a line-level preamp offered more gain and more clean watts than any of the headphone amps I used. But! Don’t forget…
These headphones are all full-range transducers with high ruler-flat impedances and near zero phase rotation. They are pretty much pure resistance. They are also, compared to box speakers, extremely sensitive: the Abyss requires only 320mV to reach 90dB SPL. Most importantly, there were no crossovers, voltage dividers, or filter networks. Nothing was gumming up the combustion chamber or messing with the compression ratio. There was no time-smearing energy-robbing mishegas in some black hole between the amp and the quivering cones.
I am explaining all this because I strongly believe the full-range, crossover-less, benign impedance, high sensitivity, and direct connective-ness, that headphones offer should – and could – be a model for floor-standing audiophile speakers. I believe I have experienced our audio future and it is simple, sensitive, resistive, and direct. |
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