PA1 all-in-one phono amp, headphone amp, pre-amp

Features:

● Reference class preamplifier.

● 8W Class A balanced headphone amplifier with slightly warmtone.

● No large loop feedback phono amplifier with tube like sound.

● Self-holding relay resistor array for lossless volume control.

● Self-holding relay controls phono amplifier impedance and gaincontrol.

● Delayed power on and instant power off for better protection.

● 2 XLR and 1 RCA line input, 1PHONO   input.   1 XLR and 1 RCA line output.

● 50W built-in linear power supply, optional 240W external powersupply.

● CNC machined solid aluminum case.

The preamplifier is the soul of an audio system;it can not only control the signal level but also plays an important role inthe audio system and is the "only way" for us to pursue the perfectsound quality. Important details in music play back such as timbre, vibe,transparency, musicality, and micro-dynamics can only be fully displayedthrough an excellent preamplifier. A good preamplifier will also make it easierto match the sound source, cables, and power amplifiers, thereby optimizing theperformance of a sound system to another level.

There has always been a reference gradepreamp in Yulong's sound audition system. After more than ten years ofcomparison with various classic preamps, and countless times of polishing andupgrades, its sound performance was proven excellent in most playbackcombinations from entry level to high-end. We further enhancedthis architecture with the latest software controls, and aftermany days and nights working on sound adjustments and optimizations, we presentyou the Yulong PA1, an outstanding all-in-one phono amplifier, headphoneamplifier, and preamplifier.

Its phono stage is the culmination of ourexperience in vinyl playback in recent years. It uses transistors to achieve aneffect like a step-up transformer plus a tube phono stage. The moving coil (MC)amplification utilizes a two-stage amplification without large loop negativefeedback. The input is a constant current source differential amplification withlow-noise twin transistors, and the signal is then fed to an operationalamplifier that has an electron tube like sound character, followed with a passiveRIAA attenuation network and output by thetransparent-sounding OPA627BP.

This design structure has extremely wideworking ranges with input impedance and capacitance, thereby is ideal withvarious phono cartridges with different characteristics. The non-large-loopfeedback design results in extremely transparent and   micro-dynamic sound.

The practical software programmedself-holding relay matrix provides MC/MM modes and has 3 presets of gain andimpedance. In addition, there are internal jumpers reserved to change the gainand impedance to match special cartridges.

Lossless volume control has always been adifficult problem in preamplifiers. PA1 utilizes a software controlledself-holding relay matrix for this function. (Self-holding relays are differentfrom conventional relays. It only requires a level triggering pulse to maintaincontinuous operation so there is no current in the electromagnetic coilaffecting the signal after switching). The signal only passes through a64-level volume controller composed of 6 high-precision resistors. There areinput and output buffers making ideal input and output impedances, furtherimproving system adaptability and sound performance.

The headphone/pre amplifier is powered by a fullydiscrete voltage stabilizing power supply and a precise reference voltagefeatures a constant current source. The output transient current can reach anastonishing 15 amps, enabling excellent dynamic performance. The optionalexternal power supply has 240W rating, providing plenty of power and furtherimproves the sound.

PA1 uses the same structure as DA1. The chassis is madeof a whole piece of solid aluminum by CNC. Not only does it have better shockabsorption effect, but can also make full use of the case for heat dissipation,ensuring the PA1 works in cool condition.

Technical Specification