Individual String Trimpots

All of the Willcox Guitars LightWave Optical Pickup powered instruments have a unique and useful feature on the motherboard: the output of each string is individually adjustable by a trimpot. These trimpots are easily accessible by the player. Just remove the back cavity coverplate, and you will see them, all in a row, right about the middle of the motherboard. The trimpots have a range of 10dB, and they can be used in a variety of interesting ways.

Balancing string outputs: the trimpots will enable the player to attain an exact balance of string outputs, regardless of the type of strings and mix of gauges. For example, if you use a skinny top / heavy bottom set of strings, you can dial the low strings back a bit to equal the lower output of the high strings. The trimpots are usually turned up fully at the factory, except for the HexFX models, which are described below. Turned fully clockwise gives you the maximum output, and all the way counter-clockwise will attenuate the output by a full 10dB. There are six trimpots, so if you have a four or five string bass, you should turn the unused trimpots down all the way. It is easy to determine which trimpot goes with each string from the illustration above, showing a six string guitar version. If you have a four or five string bass, it will follow a similar layout, but with a different start or end point. Adjust the trimpots with the instrument plugged in so that you can do the string balance adjustment by ear.

Gain staging: if you are using a tube amp, or even a hardware or software tube amp modeler, you can find a sweet spot with the trimpots that will enable you to control your tone by using just the master volume control on the guitar. With the trimpots in the fully on position, the output will be the hottest, and you can overdrive the input tubes on your amp by turning the master volume control on the instrument all the way up, giving you a natural overdriven preamp tube tone. Turning the master volume down will deliver a nice clean tone, and in the middle will be a crunch sound, where the preamp is overdriven but not into full saturation. Likewise, if you find that the output of the instrument is too hot, and is causing unwanted distortion in your signal chain, it is a simple matter to turn the trimpots down to the desired level.

HexFX synth tracking: if you have a HexFX equipped Willcox guitar or bass, you will likely have to set the sensitivity of the guitar or bass synth that you are plugged into via the 13-pin cable. The synth box will have a setup procedure which you will need to do to pair the instrument with the device. This setup procedure typically only needs to be done one time, and the settings can then be saved into onboard memory on the synth device. The sensitivity setting is critical for proper tracking – too low or too high on the input signal will cause poor tracking. The HexFX instruments are shipped with the trimpots backed off about 50%, so you can easily find the proper range to accommodate the sensitivity settings of your particular device. The setting is typically done using a dynamic meter and sensitivity control on the synth display. Each string is selected separately, and then plucked at what would be your maximum playing volume. The onboard meter of the synth should approach its maximum, but not quite get there – just like a VU meter going to the full extent of the green but not into the red. If your output is too high and you are going into the max of the meter with the sensitivity control turned down, you can back off the trimpots until you are able to achieve the proper reading. Similarly, if your meter readings are too low when you are hitting the string hard, you turn the trimpots up until you are able to use the sensitivity control to reach the desired range. Additional HexFX settings will be explained in a separate tech talk entry, and there will be a trimpot tutorial video posted here as well.