The circuits used to drive headphones are often added to a product without careful consideration of the difficult loads presented by high-quality headphones. The most common circuit is an opamp driver followed by a 30-Ohm series resistor. The series resistor provides short-circuit and overload protection while isolating the opamp from the inductance and capacitance of the headphones. The series resistor protects the opamp while keeping it stable. In contrast, today's state-of-the-art headphone amplifiers eliminate the series resistor, and use a high current driver.Read more

We are all too familiar with the criticisms of digital audio. We have heard digital audio described as harsh, brittle, lifeless, tense, cold, and non-musical. Perhaps each of us can add our own adjectives to this list. We are surrounded by poor-quality digital systems. Our consumer-grade CD players, DVD players, HDTV sets, and portable media players are usually equipped with the least expensive digital converters available. We all know that these devices are lacking the “perfect sound forever” that was attributed to the CD in 1982.Read more

Variable-pitch features add versatility to CD players.  Unfortunately, these features usually create jitter problems.  Benchmark’s UltraLock™ jitter-attenuation system provides a unique solution that is fully compatible with variable-pitch transports.
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Absolutely … if:
1. Jitter is adequately attenuated
2. The interface supports 24-bit audio
3. The interface is “frequency agile” so that it can respond to sample-rate change requests originating from the computer
4. The interface supports high sample-ratesRead more

The output attenuators of the DAC1 and the DAC1 USB optimize the signal to noise ratio (SNR) of the interface for maximum performance. They also determine the volume control position at normal listening levels. The output attenuators are factory preset to -20 dB. This setting is required for many active speakers and power amplifiers but may not be optimal for your specific equipment. Please note that the attenuators do not affect the levels at the RCA outputs, which are designed for consumer-level signals.Read more

As a manufacturer of external digital-to-analog converters, Benchmark initiated a survey of DVD transports to determine which to recommend to their customers. The research was focused on bit-transparency – the ability to deliver the audio data on the disc to the digital output, bit-for-bit. Our research was performed with an Audio Precision SYS-2722 test station – a state-of-the-art analyzer for testing audio electronics.Read more