The tubes versus transistors debate has now been raging for well over a decade, and it shows no sign of stopping yet.
But let's sidestep that and open up another debate – transistors versus transistors. Is there such a thing as a good transistor and a bad transistor, or are they all bad compared to tubes?
Let's first think of what a transistor is, without getting complicated…
A transistor is like a fat pipe through which water can flow. The 'water' flows from one terminal called the 'collector', to another called the 'emitter'. The water comes from a great big tank or reservoir, and there's plenty of it.
In the middle of that pipe is a special control valve. That valve works using a trickle of 'water' coming in through the 'base' terminal. If there is no trickle at all, it shuts off the control valve. If there is a steady trickle, it opens the control valve fully. Therefore, the flow of a tiny trickle of water can regulate the flow of a great gush flowing through the pipe.
Substitute 'electric current' for water and you now know how a transistor works. It's not rocket science, is it?
The reason why transistors have had a bad press is that they do not feature one property that tubes have, which is 'linearity'. In a linear amplifying device, the output current varies in proportion to the control current. Thus you can amplify a signal without distortion.
Transistors are far from linear, so they inherently create distortion, but this distortion can be virtually eliminated using a design technique known as 'negative feedback'. If well-designed, a transistor amplifier can have no audible distortion at all.
But that's not the point. The whole point behind using a tube amplifier is what happens when you push it. When you go slightly beyond it's ability to amplify without distortion, you get a pleasant 'warmth' effect. And the more you push a tube amplifier, the more pleasant it seems to get. That's why guitarists use nothing else.
Modern transistor designs have evolved to the point where you can push them right up to the very limit, and they will still be distortion-free. But push them over that limit and they break up horribly – it's a very harsh sound, not musical at all.
But there is a whole era of technology that somehow has gotten lost – the early days of transistor design. That was when transistors each came in a separate tiny little can, and they had to be soldered together on a circuit board, rather than mass produced like a computer chip. In those days, designers like Rupert Neve would experiment with the various ways transistors could be put together. They would listen to the results and judge them according to musical standards.
This method of design and construction is called 'discrete' – that's 'discrete' meaning 'separate' and not to be confused with 'discreet', meaning 'not showy'.
Discrete transistor circuits of the 1950s and 1960s had character. But all that disappeared when manufacturers moved to integrated circuits, which were nothing more than bundles of transistors all contained in a block of plastic, but they had no character.
So, in my opinion, the next move in audio could be a look back to discrete transistor circuits with character. Now that really will give tubes a run for their money.