TOPAZ DESIGN IMPLEMENTATION

AUDIO CIRCUITS

In our pursuit of the benefits of each circuit topology we ended up coming full circle to what is the simplest possible circuit. (Single ended in each stage) To our own amazement, this produced an exceptional front end bandwidth that extends outward to beyond 250,000 hertz. The next step was to carefully choose the supplier for the output transformer, which is the most critical component for any single ended amplifier. Our custom outputs are exclusively built for us by AUDIO NOTE using oxygen free copper wire, while the enclosures were designed and implemented in house by us.

POWER SUPPLY

Single ended amps are more susceptible to power supply aberrations than push-pull amps. For this reason we have split the front end from the output by using completely separate power supplies including separate power transformers. This eliminates power supply feedback non-linearities.

There are many ways to design good power supplies. However, our goal was to insure a maintenance free, rugged and durable amp while maintaining the highest level of purity of sound as well. The only real choice with these goals in mind came down to choosing between using paper-in-oil or polypropylene capacitors. So we set about building both to determine if any sonic differences existed. We could not detect any sonic advantage of one over the other, so we opted for polypropylene. Combined with the four large choke filters we employ and you end up with a pure power source of the highest caliber.

We also opted to employ two power transformers to drive the single output 1200 volt power supply. This allowed us to considerably lower the mechanical hum and noise level. This is critical to increase the dynamic range of listenable music with single ended amps. (Lowering the noise floor increases the dynamic range in the same way that increasing the power output does). Each power transformer feeds a center tapped full wave rectifier which in turn charges it's own individual capacitor. Further noise reduction was obtained by limiting the peak charging current allowed by these full wave rectifiers. This also has the effect of increasing the power transfer efficiency as well as improving the life expectancy of all the power supply components. As a final step we have employed double and triple insulation on all high voltage DC lines. (Teflon on the first two layers and a PVC tubing over all) This prevents leakage and sporadic discharge from occurring which can be picked up by the sensitive audio circuitry.

PARTS

We use precision quality parts throughout. Our fixed terminal hand crafted circuit boards, while costing many times more than an equivalent printed circuit board, are well worth the expense and labor to assemble them. The sonic improvement alone warrants the expense. The ease of replacing parts and the tenfold increase in lifetime durability are added benefits that satisfied our design goals. Silver solder and stainless steel hardware is used throughout as well as Teflon insulated, silver plated OFHC copper in critical areas. Output transformers by AUDIO NOTE, circuit board blanks by VECTOR CORP., polypropylene capacitors by SOLEN, resistors by HOLCO and RCD, and WBT connectors are some of the more well known suppliers that we use.