Monday, August 10, 2009

Is The 21st Century Tube Amp Revival Still Sound?

By: Ja’Nelle B.

Having more or less inherited my older brother’s “almost” all-Cary system (a year 2000-era Cary CD / DVD player, Cary 2A3-based SET amp driving a pair of Thomas Transducers Brio horn loudspeakers) for almost a year now. Due to his job that requires him to be 12,000 miles away from home to be paid yet more money to buy a better stereo. Looking at this rig, I just couldn’t believe how something – except for the CD / DVD payer – that looks like could have entertained Bob Dylan when he was yet 12 could sound way better (maybe 20 years ahead?) that the surround-sound gear oft advertised on TV. Thus began my fascination with thermionic technology – a.k.a. vacuum tubes or valves as they say in “Merry Old England”.

Having then joined in our local ad hoc hi-fi club to better utilize my newly-inherited stereo, our local experts have repeated – almost ad nauseum - the virtues of tube amplification. Though I am quite knowledgeable about the basic aspects of solid-state circuit technology, the reasons behind why tube-based amplifiers sound so good – in a majority of cases – over their solid-state brethren can be so fascinating to someone like me. Somebody that’s born way after as the older hi-fi club members in our town used to say “The Golden Age of Stereo”. So what makes tube amps tick?

The main reason (that I can agree on) on what makes tube amps sound – in most cases – better than their solid-state counterparts is that with vacuum tubes, the electrons (or more properly the electron’s wave-function) – as influenced by the audio signal – flow freely from the cathode to the plate. Unlike in transistors where the wave-function has to traverse between holes and junctions and how they are biased. Electrons can be propelled as fast as 12 million meters per second in a vacuum tube, while in a solid-state device – including wire – it is as slow as 0.1 meters per second. Only the amplified signal’s wave-function gets sent at the speed of light in a typical solid state electronic system.

So this is probably why tube amps sound faster than most of their solid-state counterparts, and more musical too. I kind of make’s me detract from the joy of listening to my “inherited” Cary system if I think too much about it. Especially if I keep on dwelling why something designed during World War II still sounds better than the latest surround-sound gear being aggressively pitched at our local mall. So if you have some more recent explanations on why tube amps sound good – especially ones involving quantum physics – please feel free to drop me a line.


  1. Given that the Thomas Transducers Brio horn loaded loudspeakers has a sensitivity of 103-decibels per watt at 1-meter, they seem to be a good match to flea-powered single-ended triode amps like the CAD 2A3 SET monoblock. But some horn designs tend to sound colored, is the Thomas Transducer Brio plagued with this problem? I have a somewhat similar system that I inherited from my uncle except that his uses a very old Klipsh horn loudspeakers that dates back probably from the 1950s and it does sound "colored" in comparison to a Mission 731 LE.

  2. I think the "very probable" reason why in most cases (there are "reasonably-priced" solid-state power amps you know - think Michell) tubes sound way better than solid-state devices is the speed in which the electron - or electrons wave function modulated by the signal - moves inside the tube. Compared that to the extremely slow motion of the electron wave function in a typical band-gap of a semiconductor crystal, and it will be very likely that tube amps tend to sound more dynamic and speedy than their solid-state counterparts. Sadly, tubes today are low-volume manufactured items - like those "trendy" newfangled assault rifles manufactured by Knight's Armament Company open reviewed by former US Navy SEAL Richard Machowicz - thus tend to be somewhat expensive. Even those new old stock tubes (unused tubes manufactured in World War II that are still unused) had been jacked up in price since the vacuum tube revival of the 1990s.

  3. Have you tried pairing a pair of B&W Silver Signatures with your Cary 2A3 monoblocks. The B&W Silver Sigs might have a low 86dB sensitivity but it has an easy impedance load, so it is very compatible with zero negative feedback single-ended triodes like the Cary.

  4. If your Cary 2A3 monoblocks managed to work very well with the Thomas Transducers Brio - in your listening room - you should stick with them. Flea powered SET tube amps are very speaker choosy, especially if you want a timbrally accurate and powerful sound from them.
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