Overdrive® SE DAC User Manual
Empirical Audio Rev. 2.0
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. The Overdrive
provides solutions for the three most important issues with digital sources:
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Jitter
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D/A noise/distortion
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Volume control noise/distortion
This high-performance triple solution is unprecedented and delivers a totally new sound
quality level. The Overdrive is a non-upsampling DAC (no ASRC) that has an ultra-
simple analog signal path, reducing background noise and harmonic distortion to
unprecedented levels. It incorporates a preamp function that has never been tried in
ANY audio product before. This preamp function adds no devices whatsoever to the
signal path, leaving it simple and ultra-low noise. It has selectable digital filters that allow
one to tailor the sound to your personal taste. You can effectively eliminate them if you
want.
The sound of the Overdrive is simply indescribable and utterly magical. The clarity is
unlike anything you have heard before, particularly driving amps directly. Other DACs
sound muddy in comparison. The bass is tight and the detail and imaging is more than
first-rate, it’s breathtaking. Drums are rendered with more realism than any other DAC is
capable of. The leading and trailing edges and harmonics of percussion, strings and
woodwinds are delivered with true realism. Even with this level of detail and dynamics, it
still gets vocals right. The Overdrive USB DAC resets the bar for the term “accuracy” in
digital to analog conversion.
1.1. Performance
The performance of the Overdrive DAC is a result of several innovative design
breakthroughs:
1. Low jitter USB interface module or Ethernet module
2. Ultra-Simple pure Class-A analog Path
3. D/A Volume Control
4. Ultra-Linear low-noise Output Stage
5. Fully Balanced Analog Path
6. Selectable digital filters
1.1.1. Low jitter Asynchronous USB interface module:
This asynchronous USB module is the same device that we use in our popular
Off-Ramp 5 USB converter. The USB interface enables bit-perfect playback from
Mac and PC, supporting sample-rates up to 24/192.
1.1.2. Ultra-Simple Analog Path:
The analog path consists of an I/V stage (ultra-low noise op-amp) driving a single
output transistor through a coupling cap. All stages are run Class-A, so it gets a
bit warm. There are no resistors at all in the analog signal paths, except for very
small necessary damping resistors on the output. Resistors add noise, so they
are best avoided.
