Why valves?

It's a very common view that technology, engineering and manufacturing are on a trajectory of constant improvement.

Every new device or system that appears is assumed to always be automatically superior in every way to those that went before. How quickly people forget Ford's Edsel and Pinto, Quadraphonic, 8-track tape, the Ericaphon, the Concorde, and the Paperless Office. Or, cash in hand, getting stuck behind someone paying by “speedy” EFT-POS.

Given that we live in a Capitalist system, and that Capitalism is known for doing things cheaply in bulk, not for doing them well, this view is a touching article of faith. Engineers and bean-counters seldom agree.

Actually technologies go through peak points where particularly useful examples are produced which then become classics of the kind, often early in the trajectory, and whos' basic usefulness and functionality continue long after the hype is gone. Cash is one such peak point technology. Books another.

Capitalism demands a string of new models, and marketing demands that they be “differentiated” from each other. So it follows that if, by accident or design, a perfect model were produced, the next model would have to be less than perfect.

Nowhere is this more apparent than in computer software bloat and “creeping featurism”. Somehow, despite all the extra processing power and features, actual functionality sometimes goes backwards.

So resistance groups emerge, such as musicians who alone have kept the second-hand price of Atari ST520's and 1040's with Notator at around $A200-350 when all of its peers have long gone to the tip. The same is true for functioning valve guitar amps.

After a professional lifetime in electronics, almost entirely solid-state, I know I can build a “better” amplifier using transistors than valves. Except in one respect - distortion.

Sure you can get double-oh-nothing percent THD. But for one particular area of application this isn't better, it's worse because we actually want an amplifier that distorts the signal a bit, and we also want a particular kind of overload characteristic, both of which are (so far) unobtainable using solid-state devices but easy with valves.

This idea seems alien to those who have been fed a constant diet of magazine articles aimed at getting rid of audio “nasties” as Hi-Fi defines them. It comes as a bit of a shock that some non-Hi-Fi amplifier users actually want and need some of those “nasties”.

One bright young engineer suggested that I should forget valves as a dead technology and be building solid-state amps with DSP to imitate the distortions I need. Made me feel like a coweled monk muttering in Latin. But this isn't electronic engineering - it's a fashion statement.

Given the simplicity of building an amplifier using valves that gives me the real thing, I was slightly boggled at the prospect of all that complexity to get only an imitation. Moreover a very large solid-state amplifier would be required to faithfully reproduce an overdriven valve amp of lesser power. Engineers often try to redefine problems to suit solutions they already know. It's easier. So I guess I'm just an 'ol stick-in-the-mud who thinks that if I want valve sound ... (now here's a radical idea) ... I'll use valves!

If valves are only a fashion with guitarists, then it's a surprisingly durable and multi-generational one. And it's all the more surprising because it touches directly on the guitarists tools of trade, literally. A working guitar amp has a military-rough life, often being lugged and set up every night, and glass valves are at a clear disadvantage over transistors even before we consider weight, heat, size and cost. On all these factors they lose hands down.

Yet generations of hard-nosed working guitarists have continued to pay a premium and put up with the many disadvantages of valves, solely because of how they sound. All the very real advantages of solid-state are outweighed by one small but vital fact - put simply they don't do the same job.

I started my career in electronics repairing and building valve guitar amplifiers, but transistors were already starting to be used in low-level circuits. Today there are very few roles where I would choose valves over solid-state, but power amplification for electric tenor guitar, specifically, is one of them.

This is despite the fact that compared to solid state, valve amps;

• are heaver due to the large output transformer
• are more fragile due to the valves
• run much hotter
• wear out fairly quickly, requiring new valves
• have more limited frequency bandwidth
• have higher distortion
• have much worse signal-to-noise ratio
• are easier to damage through mis-operation (forgetting to connect the speaker)
• watt-for-watt are more expensive to buy and maintain
• and are no guarantee of magic sound

I certainly feel the romance of steam, but I am also a realist, so I use a Twin-50 watt solid-state rig on stage for keyboards, and a 60 watt valve rig for guitar, both homebrew. My experience as a player is that the solid-state rig is nice and clean up to clipping, then rapidly distorts in an unpleasant raspy way with overdrive, which I avoid.

The lower power guitar rig starts out a little bit dirty and has a much more pleasant progression into overdrive with no raspy “wall” to avoid, which is just as well as guitar tends to have more dynamic range and overdrives more often than keyboard. Each type of amp does a better job of its respective role. So I'm hardly a valve infatuate.

It must be emphatically stated that a guitar amp is not simply a Hi-Fi amp stuffed in a different box. The origins of the guitar amplifier lie back in the pre-war, Big Band and Swing eras where amplifiers emerged that were specifically to amplify a guitar so it could compete in these larger, louder, dance bands. The Amplivox may be one such.

While these were a mono “Hi-Fi” of the day built in a different box it was the start of the divergence between Hi-Fi and guitar amps that continues today. Seventy years on, and despite the apparent similarities and some shared mythology, the two areas are now actually worlds apart, and I see no reason why this divergence will not continue.

Stewie Spears was once asked on Go-Set magazine if he was a “legs man” or a “boobs man”. His reply to this silly questions was “Legs or Boobs? I'll take one of each!”.

And that's my view on valve and transistor amps - you don't use a chisel as a screwdriver, different tools for different jobs.

My views on the Silicon Chip valve preamp.
My views on so-called Hi-Fi.

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