Trinity PREAMP, Руководство пользователя, Страница: 11 / 21

THE VOLUME CONTROL
The main emphasis is then placed on the volume control, and its key parameter is to maintain sound quality.
Of course, for our premier product, there was no question of using a cheap integrated volume control.
Although customary potentiometers, e.g. equipment by Alps, Noble, or Penny & Giles, have a slightly better sound than an
integrated attenuator, only switched resistance splitters produce a genuinely excellent result.
The quality of the volume control, of course, depends on the quality of the resistors and relays. As a result, the TRINITY
PREAMP uses special, application-specific, precision thin-film resistors, which have a tolerance of < 0.1%. In addition, they
have very low inherent noise and a very low temperature coefficient.
Contrary to conventional volume controls based on rotary switches or potentiometers which have impedances ranging
from100kOhms to 500kOhms, the TRINITY PREAMP volume control has an impedance of only 600 ohms.
Such a low figure is only achievable by the architecture of the volume control that comprises a number of cascaded, balanced
π-sections. A π-section of this type needs a source and a load termination. For this reason, this type of circuit configuration is
used primarily for high-frequency circuits. Since all impedances are matched, the driving source sees always the same load of
600Ohm independently which volume is selected. It is essential that the POWER AMP also sees always the same source
resistance of 600Ohm. Therefore the sound does not change with the volume setting.