David Lamkins picked up his first guitar a long time ago. As best he can recall the year was 1967: the year of the Summer of Love. Four decades later David has conjured up an amalgam of folk, rock and jazz solo guitar music for the occasional intimate Portland audience.
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location: Portland, OR USA

Facets: amplifiers, guitars, technique, technology, @musings info

Touch dynamics

How do great "touch dynamics" happen? Is it a matter of equipment or of skill? There's no short answer to this question. There's no simple formula. It's a matter of the whole being greater than the sum of the parts.

Everything matters. The more range you have in your picking-hand attack, the more you're going to be able to take advantage of whatever touch dynamics the rig has.

Tube amps certainly have an advantage. Some of the modellers - the Vox in particular - have a discernible response to touch dynamics. If you want great touch dynamics, though, you're more likely to find that in a rig that uses a tube amp. Which is not to say that all tube amps have great touch dynamics; they don't.

Some players believe that "Class A" tube amplifiers have inherently better response to touch dynamics. This a rather broad generalization that has some elements of truth. However, there may be other factors that make a difference.

First, let's distinguish between amp classes (determined by bias level) and biasing method. Marketing of guitar amps has all but obliterated this distinction. For all practical purposes, a "Class A" guitar amp is cathode-biased (i.e. using a resistor in the cathode circuit of the output stage to develop the bias voltage) while a "Class A/B" guitar amp grounds the output stage cathodes and applies a fixed negative voltage to the grids.

Why is this important? In a cathode-biased amp the bias voltage increases as you play louder; this causes the amp to compress and distort in a way that you don't get from an amp having a fixed-bias output stage. So cathode bias is one way to get touch dynamics out of a tube amp, but not the only way.

Some players believe that certain types of power tubes (EL-84, 6V6, etc.) produce a better response to touch dynamics. Again, there may be a grain of truth behind this belief. While there are some characteristics that you can associate with certain tube types, touch dynamics is more a matter of circuit design and component selection.

Output stage bias does have an effect upon touch dynamics. This is an easy experiment to perform on most amps. The amount that a bias change affects touch dynamics depends upon the amp.

There are a number of factors which contribute to touch dynamics. Some are more important than others. I'd rank them like this:
  1. It starts with the player. The more range in your picking dynamics, the better the response you'll get out of the rest of the rig.
  2. The amp is important. I'll say a lot more about this later, because this is where you encounter the most variables.
  3. The speakers have a big influence depending upon how much power they'll take before starting to break up and how they sound both at the onset of breakup and as you pour even more power into them.
  4. The guitar and pickups make a difference, too. The output level of the pickups determines how hard the amp will be pushed. The tonal balance (with contributions from both the guitar and the pickups) will also affect the touch dynamics. So will pickup height, polepiece adjustment, and string gauge.

OK, back to the amp... There are a lot of things that can contribute to touch dynamics. Keep in mind that presence of any of these items doesn't necessarily mean that an amp will have good touch dynamics, any more than the absence means that an amp won't have good touch dynamics. It's a matter of how all the pieces fit together. These are listed in no particular order:

It's quite difficult to predict how an amp will behave by looking at its design. You're better off playing a bunch of amps and then learning about what design features distinguish one from another.

As far a good combinations, here are a couple I have found:

Again, though, it all starts with the player... I've learned to coax usable touch dynamics out of a wide variety of amps.

October 26 2006 05:26:11 GMT