From bruce@ashbysolutions.com Thu Jul 31 04:28:05 2008
Subject:The Human Ear as a Measuring Device

Hi All,

I've watched this thread with interest. Here is my $0.02USD ...

There are certainly cases where the available measurements can't back up differences that musicians clearly hear in their gear. However, musicians have a tendency to carry this beyond the point where differences can clearly be demonstrated.

A case in point would be guitar stomp boxes and batteries. Some players (ex: Eric Johnson) claim that their ANALOG stomp boxes "sound better" with old-fashioned 9V batteries. There's a reason for that, one backed up with rational, scientific measurement: Old-school 9V batteries really are 9V when new; alkaline batteries are about 8.4V, and rechargeables are more like 7.5V. Thus, different batteries provide more/less headroom in an analog circuit. Also, battery types have differing discharge profiles -- the voltage in some of them decays with a gentle, linear slope, while others tend to remain at one voltage, and "drop off the cliff" at the end of their life. And finally, different battery chemistries allow more peak current drain than others. So, compared to an old-school battery, some types appear "old" to the circuit right out of the box.

When used in a DIGITAL stomp box, however, these differences may not even matter. Most digital electronics are designed to work over a wide voltage range, and many of them have internal regulators. But, if a guitarist is used to hearing a difference in some gear, it's easy to transfer that opinion to all gear. The same thing can be true of $50 cables vs. $15 cables, hand-wired vs. PC boards, etc. Sometimes it makes a difference, but blindly carrying the "rule" to all situations doesn't make sense.

Using premium parts falls into the same trap: If I use gold-plated parts for EVERY piece of a design, it may sound better than the same product built with other plating. However, that doesn't necessarily mean that "gold-plated parts sound better." It means that SOME areas of the design benefit from premium parts, and I decided not to take a chance on which ones were necessary.

In particular, as already mentioned, the type of power supply used in a digital keyboard like the CX-3 doesn't matter, unless the designers didn't follow good practices. (I suspect that they did.) The choice of a transformer-based supply could be as simple as, "We already have this reliable, low-noise supply from another product that will work fine. Drawbar organs are comparatively low-volume, so let's not re-design where we already have a solution."

Regards,

-BW
--
Bruce Wahler
AshbySolutions.com™
978.386.7389 voice/fax
bruce@ashbysolutions.com

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