There has been quite a bit of discussion as to which K40 control panel is “better”. This article will cover each of these panels and their differences.
K40 ANALOG CONTROL PANEL
The standard analog panel is preferred by a good majority of somewhat seasoned K40 laser users and modders. It has no electronics and displays to fail and the analog meter shows you exactly what your tube current draw is.
This configuration also affords easier panel customization and more room for extra displays, switches, etc… Sometimes simpler is better. This is one of those times.
This panel is perfect especially if you plan to upgrade controllers at some point. With the Cohesion3D, for instance, you dial in your max current once and then never touch it again. The controller does the rest.
K40 DIGITAL CONTROL PANEL
The digital control panel looks neat but not only contains additional electronics and circuitry that could fail but the percentage of power displayed is not 0 to 40 watts. it is very very easy to overdrive and damage your tube because you don’t really know what “35%” is.
The “percentage” is based on the maximum possible output of your power supply. 100% power on your machine may be 20mA or 38mA. Without a milliammeter you can not reliably know how you are driving your tube.
You can (and should) add a current meter to this configuration. You can also add a potentiometer and make yours a simple, reliable analog panel and remove the bulky display and keypad.