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The Vacuum-Tube Lie (and Tubes Done Right)

post #1 of 4
Thread Starter 

Over the last few years, and after talking to a bunch of audio engineer / designer types, I've generally come around to a more numbers-oriented, blind-testing based, objective view that was espoused by the Audio Critic (and now by people like NwAvGuy).  There are plenty of threads here (and all over the web) about the 10 biggest lies in audio, but I want to ask a question about Lie #2 -- the vacuum tube lie.  Aczel claims that tubes are a scam, and can only sound better than solid state if (a) it's a figment of our imagination (i.e. placebo) or (b) it's a deliberate pleasing coloration that solid-state designers could easily match if they wanted to design a product that is unfaithful to the music.

 

Is that generally thought to be correct? I've had a bunch of solid-state and tube amps through my system, and the tube amps have generally sounded better to me. I am a big fan of the Benchmark built-in amp (in fact, I've kept the Benchmark after comparing it to the Phoenix, Phonitor, GCHA, Heed, Auditor, GS-1, and probably many more solid-state amps), but honestly, the Zana Deux and the MPX-3 that I've had for a long time before selling them were much better sounding amps.  I guess I can't say for sure that it wasn't placebo, but my HD800 was almost unlistenable on the Benchmark, whereas it sounded amazing with the Zana.  And if that's indeed coloration that I'm hearing, and that coloration does make the tube amps sound artificially more pleasing, why aren't more solid-state manufacturers replicating that sound?

 

I guess I had two rookie questions: (1) is the Audio Critic correct that tubes are an obsolete technology and that anything tubes can do solid state can do better; and (2) what tube amp manufacturers, or which specific amps, do you think are "tubes done right" from a scientific perspective, or does such a thing not exist?


Edited by seacard - 2/23/12 at 6:00pm
post #2 of 4

You can see the power amplifier page of English wikipedia. It has a section for tube amplifying.

I think it's very illustrating.

 

Tube added much harmonic sounds to the music. These harmonics are usually 2nd harmonic which means they are an octave higher than the original tone.

To imaging this, you can compare the sound of single note, and a simple octave chord played by a piano.

I'm somehow oversimplifying the problem but this is the simple way to explain the question.

 

So, tube is not for fidelity. It's coloring, making the tune fuller than the original sounds.

 

Also, tube amplifying's "design" is generally simpler than solid state amp. (Not the cost! Tube is simple in design but not cheap in building well.)

Why? Because solid state amp's unit are a lot more sensitive to small change in the current, voltage, and many other factors. 

And solid state amp are required to perform low distortion, which means more prone to these small effects.

Unlike tube amps, Tube have such great amount of inborn harmonic effect that the small distortion effect of the circuit can be easily ignored.

 

 

Well, I'm not telling the entire story but this is the general picture of it.

Tube would always be a good choice, but in seeking "Fidelity." I'd recommend you go for good solid state amp.

 

Though I myself don't see really such a point in all "fidelity." 

Tube is GREAT  :)

 

P.S.

 

If you're interested in this question, would you mind take a small test for me?

Here's the testing poll thread:
http://www.head-fi.org/t/596966/could-you-here-the-difference

It's a small emulation for both SS amp sound and tube sound.

I have not stated which file was which, so it's a kind of blind test.

See which got more people like it.

Give it a try!

 

I'm going to release the answer of which was which soon. 

 


Edited by killkli - 2/23/12 at 6:47pm
post #3 of 4

There is a common mis-perception that tubes somehow create certain amounts of 2nd order harmonic distortion. A lot of this depends upon the circuit.

 

Second order harmonic distortion still sounds like crap (at least to me), just much less crappy than 3rd order or odd order harmonics. Over-driven tube amps do sound better than solid-state amps (think guitar), but Hi-Fi equipment shouldn't be over-driven like that in the first place.

 

The ZD amp (mentioned above) has a very simple circuit with with very little global feedback compared to many solid-state circuits. The electrical characteristics of tubes and transistors lend them to particular types of designs.
 

post #4 of 4

Big differences could also be attributed to the inherently higher output impedance with tube amps. Many nice SS amps have almost 0 output impedance and therefore a high damping factor. You could build a simple adapter with one resistor in series with each headphone driver to increase the output impedance / decrease the damping factor.


Edited by xnor - 2/24/12 at 3:52am
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