Vacuum tubes v. TransistorsI
t may surprise you to discover the vacuum tube in the macro photo above was part of an on-board sound section found on one of seven motherboards from AOpen for their vacuum tube line
. The AX4PE (reviewed at Techtree)
was a motherboard designed to offer Audiophile Sound in a PC format. While I was one a handful whom felt the concept had merit, it was extemporaneous at best and just didn't take. The ethos of the modern PC has been winterization and when it comes to High End Audio and the reproduction of sound, physics and electronics move in the opposite direction. This is why your Blackberry or Kiwi-Strawberry is incapable of producing realistic sound on its own. Headphones don't count, although even with- there's only so much you can do given the source data compressed until it's literally screaming in your ears. And this leads us to the tube versus solid-state debate and why that topic has leaned in favor of thermonic devices (tubes) since the introduction of digitally converted sound. I give AOpen credit for trying; I have working on a vacuum tube based sound-card as a plug and pay option. Insofar as AOpen, their last effort would see no less then three vacuum tubes (seen below a prototype).
The audio community has been divided over the topic of vacuum tubes
(or mosfets) since the introduction of solid state. The debate centers on so many things but I would have to cite neutrality
as pertinent to our discussion. Most Audiophiles would probably claim neutrality is integral to accurate sound reproduction. Those whom feel transistors offer more detail, resolution and accuracy argue the electronics should not lend themselves to the sound, or distort the signal in any way. In this respect many believe the vacuum tube is guilty of being overly warm, thereby adding "color" to the sound. Audiophiles seeking a more analytic sound may look to USA designers such as KRELL
, and Mark Levinson
. One of the best sounding amplifiers I've heard were Jeff Rowland
. The Rowland Model 10
dual-monorail aka LM3886 utilizes six of these National Semiconductor transistors per channel. Below in the first thumbnail on the left, a close-up of the Model 10 innards (LM3886T
), and in the final three thumbnails Jeff Rowland's Concerntra integrated amplifier also featuring six LM3886T transistors per channel.
While transistors traditionally exhibited better bottom end control (tighter) and more detail in the highs, this is not necessarily due to transistors being any more or less "neutral." For those whom are under the impression transistors are more neutral because they offer lower THD (Total Harmonic Distortion) in High End Audio the opposite is true, which we'll discuss shortly. As far as the accuracy of tubes the quote below from a Tiny History of HiFi
may shed some light on the topic:
...vacuum tubes, and especially triodes, continue to be the lowest distortion amplifying elements ever made. No germanium or silicon transistor, JFET, or MOSFET has ever approached the distortion performance of the direct-heated triodes, with indirect-heated triodes following closely behind. In addition to low distortion in the absolute sense, the distortion spectra of triodes is favorable, with a rapid fall-off of the upper harmonics. (This is less true for beam tetrodes, pentodes, or solid-state devices, which are intrinsically less linear and have higher-order distortion curves.) The sad fact is that solid-state devices have linearity well down on the list of design priorities, with feedback needed to clean up devices that were never primarily intended for audio.
Vacuum-Tube aficionados have a simple philosophy, the hardware itself should be neutral, but it must be musical, conveying the essence of the music. The warmth indicatory of vacuum tubes comes far closer to evoking the emotive element of recorded music then any other electronic device. One mans "distortion" is another mans palpable mid-range and by the same token, what is analytical to one listener may sound forward or bright to another. In last several years vacuum tubes have found their way to the IPod and while there is no doubt an element of marketing in many IPod tube-based docking stations, the concept of tubes employed in DAC circuitry is valid. Here we have a list of the Top Ten IPod Tube Docking Stations
. On that list an interesting product which may have sonic potential might be the Gakken DIY Tube IPod kit
, for just $150 this may be better then the rest. As for aesthetics alone, Rockridge Sound's VTS-384 is real eye-candy, but will it sound as good as it looks?
Onto digital conversion...