OAD Ultrafidelity - Padma - Preamplifier

The preamplifier remains the central control unit, the real heart of the hi-fi system. The preamplifier is irreplaceable for sonic reasons.

The Padma sports a fully CNC remote control and chassis of premium grade aluminium, ensuring an inert and stable base. Available in silver or black, its robust and sophisticated design ensures an efficient assembly and timeless appearance around an innovative design.

Developing a new preamplifier

Since the release of the CP1 six years ago (2016) the entire wealth of OAD's experience was utilised to develop the new Padma Preamplifier. The Padma represents an uncompromising harmony of technology, styling and functionality, boasting ultimate performance and sound quality that ushers in a new era of the preamplifier.

Dual Balanced line stage to new heights

In the CP1, the all discrete line stage which elevated single ended circuits to an nnparalleled level is further elevated by driving two such units in parallel, resulting in the Dual Balanced Topology which significantly improves electrical and sonic characteristics. Compared to the CP1 model, the already excellent noise level is reduced by a further 30 percent.

Revolutionary volume control

The volume has an attenuation range of 73 steps, 0.5dB per step. Balance range is +/-6dB (double the volume) in precisely 0.5dB steps. The volume control uses laser cut precision, lowest-noise and zero-induction resistors on a single die that have a zero temperature coefficient. Hence there is no possibility of change in resistance. The attenuator has a constant output impedance and extremely low Johnson noise that is consistent across all volume settings. Potentiometers and stepped attenuators cannot give superior right to left volume level matching that is critical when listening. Potentiometer based volume controls, such as even the best (Alps Blue Velvet) typically have something like +/-20% tolerance so the left to right channel matching can easily be out by as much as 2dB. The output impedance of such volume controls (and associated Johnson noise) also varies by where the volume control is set. For example, a 50K ohm volume control set to the middle will have 15 times or 23dB the noise of the Padma volume control. The Padma is immune to influences like mains quality and the choice of interconnects. The volume control directly controls the gain of the output stage via a digital link. This digital link allows the volume circuitry to be placed as close as possible to the input and output connectors to minimise the signal path for optimal purity. Accuracy, linearity and dynamic range of this arrangement is much greater than those of stepped attenuators and potentiometers. Operation is smooth and glitch free.

Dual Mono Layout

The entire path for all signals from the input connectors to the outputs is fully balanced. Audio purity is maximised by using minimal components in the signal path. Moreover, crosstalk is virtually eliminated by using a dual mono layout for left and right channels. Once again, only low-noise and zero-induction resistors are used.

Experience the ideal image for music playback that the Padma delivers. The music echoes throughout a space surrounded by silence.

Volume Sensor Position Mechanism

The music signal does not pass through the volume sensor mechanism. It is just a position sensor to be able to set the desired volume. However, the look and feel of the volume knob is very important to audiophiles. A stepper motor delivers an elegant solution to volume control whilst still maintaining the timeless appearance and feel of a traditional knob.

Specifications

• Line Level Inputs: 3 Balanced and 6 Unbalanced
• Line Level Outputs: 1 Balanced and 1 Unbalanced, 1 Balanced and 1 Unbalanced Home Theatre outputs
• Overall Gain (dB): -63 to 9.7
• Frequency Response (kHz): 0 - 650 -3dB @ 1.8VRMS Output
• Maximum Output: >20V RMS
• Signal to Noise Ratio (dB): >110dB A-weighted input shorted
• Weight: 13 kg (28.7 lbs)
• Dimensions (WxHxD mm): 438 x 126 x 353 (17.2” x 4.96” x 13.9”)