Empirical Audio Overdrive SE DAC User Manual © 2012
Overdrive® SE DAC User Manual Empirical Audio Rev. 1.0 Critical – read all red warnings first to prevent equipment damage 1. Technology/Design The Overdrive DAC incorporates our excellent low-jitter USB interface technology and breaks new ground for D/A converter technology. The Overdrive design philosophy is “less is more”, with one of the simplest analog paths ever devised.
1.1.3. D/A Volume Control: The revolutionary volume control is accomplished without any added parts to the line-output signal path. It is not an entirely digital or entirely analog volume control. It is a little of each actually. The volume is adjusted by changing the reference voltage of the D/A conversion. It does NOT adjust attenuation of a resistor divider, change the gain of an amplifier stage or truncate bits in the digital data. All of these would add noise and/or distortion to the signal.
This is a key element contributing to the performance of the Overdrive SE. A separate Substation enables more densely packed energy storage for each voltage, more optimized layout and creates space between the magnetics in the supplies and the Overdrive Chassis to eliminate coupling. 2. Break-in All electronics needs a period of break-in. New capacitors and dielectric insulators must stabilize with voltage and current applied.
will have the least range, so the lowest volume will still be loud. If the range jumpers are set for “Max”, the volume control when at the minimum will be very quiet. This allows the volume to be tailored so that a fairly wide arc can be used in adjustment for track-totrack amplitude variation. The default factory setting is “Medium”. Make sure the Overdrive is powered-off for this adjustment. The front panel and knob must be removed to access these. 4.
4.1.1. Substation Back Panel 4.2. AC service tips Make sure that you use the same circuit from the AC panel for the computer and the Overdrive SE. Different circuits will potentially originate from different phases and may cause ground reference voltage differences with resulting high-currents in the ground. This can potentially damage other components in your system.
5. Overdrive Back Panel Connectors 5.1. Digital Inputs 5.1.1. I2S input The Overdrive I2S input is compatible with the Empirical Audio I2S standard. It can be driven with a Pace-Car or an Off-Ramp. It supports up to 24/192. 5.1.2. S/PDIF coax input The S/PDIF coax digital input can be driven from any audio device with digital output conforming to the S/PDIF standard IEC-60958. The input impedance is 75 ohms.
5.2. Analog Outputs 5.3. RCA – Single-ended outputs The RCA outputs are designed to drive a preamp, amplifier or high-impedance headphones. These are AC-coupled, so there is a delay in the power output from them on power-on in order that the DC voltage settle-out. The line output level from these is 2.3VRMS in high-gain mode and 1.0VRMS in low-gain mode. The volume control reduces this. On power-down, the outputs disconnect from the output drivers and short to ground.
6. Overdrive Front Panel Switches and Indicators 6.1. (3) Input select toggle switch Selects between USB, I2S and S/PDIF coax digital inputs. Down position selects S/ PDIF coax, middle position selects I2S and up position selects USB. 6.2. (2) Digital Filter Select toggle switch Selects between Low, Medium and High frequency roll-offs. High is the down position, Low is the center position and up is the medium position. It is recommended to use down position always.
6.7. Data Error Indicator Illuminated indicates that there is no valid data coming in on the selected digital input. 6.8. DC Power Indicator Indicates that DC power is applied to the DC input connector.
7. Software Software drivers must be loaded to support the USB interface for both PC and Mac before connecting the USB cable. For operation on a PC, Kernel Streaming is recommended to bypass Kmixer on XP machines and WASAPI on Vista and Win7 machines. 7.1. USB Drivers Drivers are located on the included CDROM disk. Load the appropriate driver for your machine and OS and execute it on the computer before powering the Off-Ramp 4 or connecting the USB cable to the computer for the first time. 7.2.
• • • Select HiFace Kernel Streaming or Empirical Audio 192 async Kernel Streaming for output Check that both the red and yellow LEDs are off on the Off-Ramp Play a track or playlist using your player application 9. Specifications: Inputs: 1. USB 2.0 or 3.0, Mac or PC, up to 5 meter USB cable – up to 24/192 supported 2. S/PDIF coax – Canare 75 ohm BNC - up to 24/192 supported 3. I2S (Empirical standard RJ-45) – up to 24/192 supported 4.
