Im Nachlass des Wolfgang Hasselbach sind ganz besondere "Stücke" enthalten -  unter anderen Broschüren über (zum Beispiel) Cabasse aus Frankreich - so auch diese QUAD Produktübersicht aus dem August 1959.

BRAUN aus Frankfurt hatte ja bei Mister Walker die Fabrikations-Lizenzen für 500 Paare der BRAUN LE1 Elektrostaten erworben (und damit Schiffbruch erlitten). Mr. Walker war gegen deutsches Geld nicht abgeneigt, wollte aber weiter kein Wissen rausrücken, schon gar nicht an die Deutschen. Herr Hasselbach war mit seinen Problemen im Gepäck mehrfach dort in England, holte sich aber fast jedes Mal galant und höflich eine indirekte Abfuhr. Mr. Walker hätte vom Alter her sein Vater sein können. So war das damals 15 Jahre nach dem 2. Weltkrieg.
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The QUAD II power amplifier contains no controls and may therefore be mounted inside the cabinet, leaving only the control unit panel (and that of the radio tuner if fitted) visible on the outside. Stability, and hence performance are entirely independent of signal or load conditions and the amplifier is therefore suitable for use with any loudspeaker arrangement. The performance specification is fully maintained with random replacements from normal valve stocks without the need for matching or alignment of any kind, and the output stage uses the now traditional QUAD cathode coupled arrangement combining low distortion with an efficiency which is reflected in the compact size of the equipment. The amplifier is suitable for use in all climatic conditions.
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The QUAD 22 control unit is designed to operate with two QUAD II power amplifiers - but it may be used with one only for monaural operation if required. Selection of stereo or monaural is by push buttons, as also are the choice of programme and record equalisation characteristic.

The other front panel controls are all equally straigt-forward in operation and yet comprehensive in ???? providing all that is necessary in an amplifier for the closest approach to the original sound so that enjoyment of the music is not impeded by problems of manipulation.

The curves illustrated opposite show the slopes of response provided by the bass and treble controls, and the manner in which the filter may be adjusted to provide the widest possible frequency range consistent with minimum distortion in each programme source. In the cancel position there is a useful reference standard for comparison with the settings of the bass, treble and filter controls found by aural assessment, and the balance control provides for adjustment of balance between stereo channels.

The gramophone input may be accurately matched to any pickup by choice of the correct plug-in adaptor unit, indicated on a chart supplied with the amplifier, while another chart shows the push button combinations required to provide correct equalisation for different makes of record, old and new.

FREQUENCY RESPONSE
Cancel position:
Radio and Tape inputs: 20-20,000 c/s ±0.5dB.
Microphone: 20-20,000 c/s ±2 dB.
Gramophone Maintained over 20-20,000 c/s withini 1dB
Bass and treble controls: ±1.5 dB of published curves.
Filter frequencies: 5 Kc/s, 7 Kc/s, 10 Kc/s.
Filter slope: See curves.

INPUT SENSITIVITY (at 1 Kc/s for 1.4V rms output)
Radio: 70 mV rms. Load impedance 100,000 ohms.
Tape: 70 mV rms. Load impedance 100,000 ohms.
Microphone: 1.5 mV rms. Load impedance 100,000 ohms.
Pickup: Depending upon adaptor unit.
Basic sensitivity prior to compensation 400 mV rms.

DISTORTION (1.4 Vrms output): All controls level: Any input: 0.02%. Least favourable arrangement of controls: /ess than 0.1%.
NOISE
Total hum and noise: Better than -70 dB.
Noise: -80 dB or where applicable, the equivalent noise of the pickup load impedance at the input.

OUTPUT
Control unit to power amplifier: 1.4 V rms.
Tape outputs: Peak signal approx. 0.25 V rms.
Maximum loading 500,000 ohms and 200 pF.

INTERCHANNEL SPECIFICATION
Cross talk: Better than 40dB 20-20,000 c/s.
Gain stability: With any volume setting and tone controls level: Less than 1dB between channels. With any volume setting and tone controls varied: Less than 2dB between channels.
Balance control: Provides up to 9dB unbalance either way.

POWER SUPPLY
The unit takes its power from the main amplifier as follows :
220V - 4mA. Plus current taken by tuner units.
VALVES
2 x EF86 (Z.729 or 6267). 2 x ECC83 (I2AX7).

MECHANICAL
Front panel: Die cast, stove finished silver fawn.
Knobs: Matt brown. -Chassis: Steel: Cadmium plated. - Cover: Steel: Stoved steel grey.
The complete unit is electrically and mechanically suitable for use in all climatic conditions.
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The Quad II Control Unit is the monaural counterpart of the Quad 22 and is very similar in all the main features except, of course, for those associated exclusively with stereo.

In the QUAD FM Tuner careful control of the bandwidth throughout the receiver makes it possible to obtain low distortion and high noise rejection while the limitation of frequency response is that imposed by the transmitter rather than the receiver assuming correspondingly good amplifiers and loudspeakers.

THE QUAD ELECTROSTATIC LOUDSPEAKER is a design of modest size intended for the highest grade of music listening under domestic conditions. It is suitable in rooms from 1,000 to 5,000 cubic feet, and is capable of providing distortionless reproduction under such conditions up to a volume level similar to that experienced in the concert hall.

It is designed with every emphasis towards the natural, non-fatiguing and unobtrusive quality desirable for serious listening to music of all types. There is no doubt that the very unobtrusiveness of the speaker will seem an anticlimax to many people because of the complete absence of "spectacular Hi-Fi." For the rest, there will be a degree of naturalness which has given rise to such expressions as "Freshness," "Relaxed," "Transparent," "Window on the Orchestra."

The loudspeaker is supplied complete with built-in networks for operation direct from a low impedance amplifier source and incorporates its own polarising supply ready for connection to AC mains.

The loudspeaker is intended to be used with a standard QUAD II amplifier. Other amplifiers may be used provided they are designed or adapted to meet the specific parameters given on this page. Failure to meet this requirement will result in inferior performance or unreliability.

The loudspeaker is free standing and does not require the use of a corner position. Position is, in fact, not critical, except that this speaker should not be operated closer than 2 feet from any wall or large surface parallel to the plane of the loudspeaker. Both front and back radiation should be as unrestricted as possible.

Good musical balance will be obtained when the listener is seated in the area covered by an angle of nearly 90° symmetrical to the front of the loudspeaker.

TEMPERATURE, HUMIDITY
The loudspeaker will withstand a temperature of up to 45° C. and is thus unaffected by normal domestic temperature. The loudspeaker will operate indefinitely with Relative Humidities of up to 90% and will safely withstand reasonable periods of up to 100% RH. If, however, temperature and humidity conditions are sufficiently severe and prolonged that moisture is able to precipitate inside the loudspeaker, then damage is likely to result. This may preclude the use of the loudspeaker under certain tropical conditions. The loudspeaker is completely sealed in plastic film and is immune from the effects of dust.

SPECIFICATION
MAXIMUM OUTPUT
6' on axis In free space 93 dB referred to .0002 dynes/cm2 in frequency range 50c/s - 10Kc/s.
l00dB referred to .0002 dynes/cm2 in range 70c/s - 7Kc/s.
Total Integrated radiation equivalent to 95 phons in enclosures up to 5,000 cubic feet with average reverberation.

BANDWIDTH
45c/s - 18Kc/s. Rate of attenuation asymptotic to 18 dB/8ve.

DISPERSION
Approximately 70° Horizontal, 15° Vertical.

IMPEDANCE
30-15 Ohm in range 40c/s - 8Kc/s falling above 8Kc/s (see power amplifier requirements).

AC POWER CONSUMPTION
Negligible. ( = vernachlässigbar)
AC VOLTAGE RANGE
100-120, 200-250 volts 50-60 c/s.
DIMENSIONS
See drawing.
WEIGHT
Net 39 lbs. (17.7 Kilos approx.)

(Preise im Herbst 1959 in England) :
PRICES (Applicable to United Kingdom only)
QUAD II POWER AMPLIFIER 22.-
QUAD II CONTROL UNIT 19.-
QUAD 22 CONTROL UNIT 25.-
QUAD F.M. TUNER 21.-
QUAD ELECTROSTATIC LOUDSPEAKER 52.-

(alle Preise in Pound Sterling) + tax

The ACOUSTICAL MANUFACTURING COMPANY LTD.
HUNTINGDON, HUNTS.
Telephone: HUNTINGDON 361
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