Pearl

Audio Circuits

We've retained the grounded grid configuration which we deem to be the best possible circuit topology for line level amplification. This circuit, like the Opal, maintains an exceptional bandwidth that extends well beyond 500,000 Hz. Our primary design philosophy that less is better than more has been fully developed in the Pearl preamp.

Power Supply

The power supply is built on a separate PCB terminal board and is similar to the Opal in that we have implemented a double pye filter network using two large chokes in conjuction with electrolytic and polypropelene capacitors to maintain an ideal DC voltage. A passive Zener network shunt regulator stabilizes the DC Voltage level. We have again avoided using active feedback in order to maintain the speed of the power supply in relation to the extremely fast analog circuitry. Stability is ensured by the use of a large electrolytic reservoir capacitor and speed is enhanced by using a large (30 µF) polypropylene film capacitor as a final filter stage located directly on the analog terminal circuit board. The 200 Volt DC power supply completely eliminates all noise and ripple to below what our test instruments can detect. An AC power line filter is also used to prevent unwanted noise and hash from entering into the unit.

Parts

We use precision quality parts throughout. Our fixed terminal hand crafted printed circuit boards are a new technology used in contruction and is a first in the industry. This innovative feature increases the ease of replacing parts and the increased durability are added benefits resulting from this board construction. These boards are held elevated from the surrounding metal chassis to avoid any capacitive coupling between components. We import from Denmark our stepped Elma volume controls that use 0.1% precision metal film surface mount resistors. For selection and balance, we use the Shallco military switches similar to those used in the Opal.