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Quad 33

Stereo Control Amplifier (1978)

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Quad 33


The Quad 33 selects and controls the radio tuners, gramophone pickup and tape recorder connected to it and feeds the loudspeakers via the power amplifier, providing for stereo, mono on either or both channels, from all inputs, plus monitoring and track selection facilities for tape.

Quad units may be used either free standing or mounted in a cabinet with plenty of scope for individual preference in layout.

The standard Quad system of mounting is used, requiring only a rectangular cut-out for which a template is provided.

The controls are comprehensive but simple and are logically grouped to facilitate selection and control of the programme.

The filter is essential with modern good quality speakers and helpful at any time.

It removes surface noise, tracing distortion and similar shortcomings in the upper frequency range of the recording or broadcast, and the two control filter system achieves this to a very fine degree without intruding unnecessarily into the harmonic range so essential for realistic reproduction.


Frequency response: 30Hz to 20kHz

Total harmonic distortion: 0.02%

Input sensitivity: 2mV (MM), 100mV (ceramic), 100mV (line)

Signal to noise ratio: 70dB (MM), 85dB (line)

Output: 100mV (line), 0.5V (Pre out)

Dimensions: 260 x 92 x 165mm

Weight: 3kg


instruction/owners manual   English - Quadmann

issue 2 service supplement   English - Quadmann

flyer   English -

issue 6 schematic   English - Jacques51

service data   English - Yeon-Woo Jeong

Related Catalogues

The First 50 Years


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Reviewed Feb 21st, 2015 by desertdog

Still in use today, best tone controls ever.

Reviewed Oct 26th, 2013 by davjoma

Had mine since new in 1977. Coupled with 303 amplifier driving Spendor BC1s. A classic mid-range system. Sounded excellent back then and still does today. i've had the pre-amp serviced twice by Quad to rectify some minor faults. Otherwise perfect.



re: 33

Have recently inherited a Quad 33. Although there is output from both channels, the stereo has been compromised, with instruments (and vocalists) from familiar tracks being, quite simply 'airbrushed' . Would appreciate suggestions as to how to put this right.

QUAD 33 interconects

Recently bought a new Plasma HDTV which only has optical audio outputs. All my older TVs had RCA audio output jacks which I could easily connect to the QUAD 33/303 preamplifier which drives my QUAD ESL-57 2 channel speakers. Do you know of a way to take the optical audio outputs of the Plasma HDTV and turn it into RCA outs ?
Wade Bunz

re: QUAD 33 interconects

toslink to analog conversion

Google the subject. Looks like there are devices out there.

This website is not affiliated with or sponsored by Quad. To purchase 33 spares or accessories, please contact the company via their website or visit an authorised retailer.