Origin Live - Discovery 2 - Phono stage

When vinyl is played up to 90% of the total voltage amplification takes place in the phono stage. This makes the phono stage a most critical component in the audio chain. Most integrated amplifiers and preamplifiers are unable to offer truly high-grade vinyl playback because they are built from an understandably small proportion of a total component budget.

Similarly, an integrated amplifier or preamplifier nearly always shares its internal power supplies with a number of analogue, digital and other control systems. It is not hard to see therefore how the tiny signal from a low output moving coil cartridge, which is 20,000 times smaller than a typical digital signal, can be seriously corrupted.

These reasons are what makes investing in a dedicated high-grade phono stage one of the most effective system upgrades.

Purpose

The Origin Live Discovery 2 phono stage is designed to vastly improve on integrated preamplifier limitations by virtue of innovative circuit design, the use of high-grade audio components and a significantly over specified external power supply. It amplifies the output from most moving magnet and moving coil cartridges and couples exceptionally well with coil impedances as low as 4 ohms.

Unlike many other phono stages, the Discovery 2 connects the cartridge directly to the amplification circuitry. There is no initial DC blocking or filtering in the electrical path to degrade the audio signal before it undergoes enormous amplification close to 100dB at 20Hz.

Sound Quality

The improvements that the Discover 2 brings to a system are spectacular. An immediate observation is vastly improved speed and timing. This is an important aspect which brings listeners much closer to the original performance. Other factors are increased transparency, greater dynamics and improved levels of detail.

A highly neutral tonal balance also means there is excellent imaging capability which leads to the presentation of a 3-dimensional sound stage – so appreciated by those who understand what makes music come alive.

Technical Aspects

The Discovery 2 is a high-performance stand-alone phono preamplifier, meticulously designed and packed with innovative thinking. It exhibits unrivalled sonic qualities with low noise amplification.

Design Philosophy

The phono stage is based on work carried out by Origin Live’s long-established collaboration with highly experienced electronics design engineer Simon Clark backed by years of auditions and listening tests. It is built around a zero-feedback passive equalisation RIAA filter and ultrahigh quality amplifier sections.

Each channel is treated separately and the use of high-quality components allows the performance of the circuit to shine through. For faithful reproduction of the original recording the RIAA curve is followed as closely as possible making it flat to the RIAA standard by less than +/- 0.5dB.

Direct Path

Many external high-grade phono stages, even well-known ones, use a single ended DC power supply for simplicity and cost savings. These designs, almost without exception, need to block DC from the cartridge or else it would be destroyed. This fundamental design choice requires a capacitor to be placed in line with the cartridge and then right away, before any amplification takes place, the tiny analogue signal is degraded significantly. This degradation once amplified by up to 4000 times cannot be extracted from the original audio source.

This is why a direct path from the coil to the amplifier circuit is so important and explains in part the highly transparent sound quality of the Discovery 2.

Passive RIAA

Many phono stage designs incorporate an RIAA filter as part of a feedback loop. It makes sense to do this as the primary purpose of the phono stage is to amplify the cartridge signal whilst applying the RIAA filter. The problem with this design choice however is that the amplifiers gain becomes frequency dependant and therefore subtle but audible changes are introduced that spread dynamically across the audio spectrum in real time. The net result is a tendency for such designs to add colouration to the audio signal that reduce its ultimate clarity.

The Origin Live Discovery 2 phono stage keeps the RIAA filter squarely in the passive domain where it naturally corrects the recorded frequency response away from any frequency based, loop feedback side effects.

Power Supply

Much attention has gone into the power supply design which is critical to faithfully amplify ultralow level signals. It features several layers of filtration and regulation designed to isolate and create a pure electrical source for signal amplification.

The AC mains is first EMC filtered to remove up to 70dB of unwanted electromagnetic and high frequency interference from being passed through to the power supply.

Spike and transient suppression techniques are also used to minimise unwanted noise appearing in the audible frequency spectrum.

The DC supply fed between the PSU module and the phono stage is balanced and therefore exhibits excellent common mode noise rejection.

The filtered DC is then regulated to ensure that regardless of voltage changes to the AC mains supply the amplifier circuitry is run at a completely steady DC voltage.