Tu be or not to be
Contents
An explanation for differences in the sonic properties of tubes (Stax) versus transistors and op-amps (Hifiman Jade II) can be that tubes handle spikes and surges in voltage, distortion and clipping differently than transistors. Tube technology is characterized by an overcapacity of electrons around the cathode (the tube itself), which creates a large buffer for peaks in the voltage (of the sound signal which is after all an electronic sine wave).
Transistor amplifiers work with a protection circuit which interrupts the signal very briefly. This ‘clip protection’ doesn’t just work in emergency situations, which you may have experienced when pushing up the volume of your amplifier to the max. You hear a click, the music stops and after a reset the amplifier starts playing again. Clipping happens not only in these extreme situations, when the amplifier is set to ’10’, but actually always when the amplifier power is insufficient. And this is happening faster and more frequently than we might expect.
Imagine a speaker with an impedance of 8 Ohm at a voltage of 40V clips (to be measured via an oscilloscope), then we can apply the formula: Watt = Volt2 divided by Ohm, or 1600V / 200 Ohm = 200W. We now know that distortion occurs at 200W, so the continuous amplifier power for a clean amplifier signal will have to be higher.
A rule of thumb is that a conventional loudspeaker with a sensitivity of 90dB requires a continuous amplifier power of 500W per channel. All this is described in detail in a white paper by Roger Sanders. Tube amps do soft clipping, transistor amps do hard clipping. The result of hard clipping is clearly audible as graininess and roughness in the sound, and it is missing transient information; as a result the reproduced sound lacks timing and precision.
Conclusion
Hifiman's Jade II is an example of how electrostatuc headphone systems are able to perform sonically; fast, open, precise and also with more than enough bass punch. In a sober design and undone of bling bling, the Jade II does what it's supposed to do: play music the way it's meant to do. It invites you to listen and enjoy for hours. The asking price will seem high at first glance, but we dare say that for this money you will not find a better combination of headphones and amplifier.It's a pity there are so few brands that run an electrostatic headphone-lineup. Compliments to Hifiman for offering three electrostatic systems in three price segments. The Jade II wins in price/quality ratio. With reluctance we send this beautiful set back to the distributer. Altough it lacks vacuum tubes, warmly recommended & Alpha Approved!