Very few Hi-Fi components are as instantly recognisable as the QUAD 33 and 303, and for that we make no apologies!

Still one of the most popular models in the history of one of the world’s most poignant Hi-Fi brands, the QUAD 33 and 303 are benchmarks in almost every angle of desirable audio equipment – performance, reliability, industrial design, value and musical romance.

Overview

By revisiting the QUAD 33 and 303 components, QUAD demonstrates its authenticity, pedigree and excellence as a juggernaut of the British hi-fi world - past and present.

In listing the names involved in the development of this stunning iteration of an icon, you’ll find a calculation of close to 200 years of engineering experience and 100+ years of QUAD-exclusive design and service.

Function

The outstanding performance of the QUAD 303 is still celebrated to this day, and is largely due to the unique output circuit developed by QUAD.

In reissuing the QUAD 303 power amplifier concept, exactly like the matching 33 preamplifer, QUAD’s incomparably experienced service team was matched with the equally adept engineering team to reinvoke the design, romance and performance in a thoroughly modern iteration of a hi-fi legend.

As with the new QUAD 33, every aspect of design and performance has been analysed and re-engineered way beyond simply modernising components and refreshing of specifications.

Circuitry

However, much like the original, the new QUAD 303 maintains its faithfulness to the original by employing the famous QUAD ‘symmetrical triples’. Employed to provide a completely symmetrical output stage, greatly reducing distortion and rendering the resting current independent of output transistor temperature.

This development enables the designers to reduce distortion to emphatically low levels without sacrificing stability and to maintain this excellence under all dynamic conditions.

To put this in perspective, the lowest theoretical distortion present on the very source material will still be some hundred times greater than that the QUAD 303!

Functionality

Such a level is, of course, completely inaudible no matter how refined the test.

The use of ‘triples’ permits simple and effective control of the output current and since the voltage is also controlled, the output transistors are completely protected and must always operate within their ratings with the obvious advantages of greatly improved reliability under all conditions, without the use of elaborate and expensive circuitry.

Details

Always respected for its conservative but consistent power-output, the classic QUAD 303 was officially rated at 45W @ 8 ohms. A modest but honest output, the 303’s venerability is in the finesse of the performance, not just the raw power. The new model is thoroughly the same.

However, with some tweaking and enhancements, the 303 is loaded with a little extra power – offering 50W @ 8 ohms (70W @ 4 ohms) with a maximum current delivery of 10A into difficult loads. The original 303 was known to have issues with lower impedance loads, the new 303 has no such trouble. Perfectly suited to the more demanding requirements of the modern audiophile, it ensures any speakers – even including QUAD’s electrostatic designs – can be driven with ease. Connectivity options comprise single-ended RCA and balanced XLR inputs, a 12V trigger input and high-quality speaker binding posts. Simple, solid and thoroughly authentic, inside and out. The power output for 'bridged mode' (for use as a mono-block power amplifier) reaches 140W @ 8 ohms or 170W @ 4 ohms (bridged mono).

Description

The industrial design of the new QUAD 303 is instantly recognisable and is ‘true QUAD’. The anodised chassis CNC-routed heat sinks on either side offer enduring quality which the tank housing also provides a rugged structure that resists interference from external vibrations.