DESIGN
Instrument Preamps
Preamp noise testing
Guitar preamps require a careful balance between various design parameters such as those that define input impedance, frequency response, output impedance, noise pickup and power consumption (and hence battery life). Circuit simulation, precise component selection and PCB layout dictate the final outcome. Real life testing will then reveal how the theory compares with reality.
preamp tone control testing
With the multitude of different guitar and bass configurations, not only in terms of fundamental string frequencies but also transducer types and body structures, certain tone control configurations have been shown to be better than others. Selecting the optimum centre frequencies and boost/cut levels is carried out using both circuit simulation and ultimately listening tests.
Printed circuit board design
Circuit designs are translated to a PCB design using predominantly surface mount technologies. These take up less space, are quick to manufacture and have greatly reduced loop areas compared with through hole designs so reducing pickup of interference. Through hole components are usually limited to connectors and control pots where applicable. 3D modelling assists greatly in physical integration prior to any actual manufacture.
Printed circuit board manufacture
Once the bare circuit boards are manufactured, assembly is carried out in house for the required quantity. Every PCB assembly is tested for functionality. This may include noise floor, gain and frequency response testing plus control pot functions depending on the circuit. Many industrial control applications benefit from computer controlled test programs that ensure consistant testing is carried out from batch to batch. Results are stored for each PCB assembly to permit traceability.