Constructor Series CS1 to CS9, PL301

Since the 1960s, KEF had made the component parts of the most popular systems available in kit form for those who chose to build their own cabinets. The KEFKIT series was replaced by the Constructor Series of six kits – most of which were equivalent to Reference or C-Series products of the time.
 
Constructor Series Model CS1 (1981-90)
The CS1 was a bookshelf two-way system based on the Reference Model 101
 
Constructor Series Model CS1A (1981-90)
The CS1A was a bookshelf two-way system based on the BBC LS3/5A.
 
Constructor Series Model CS3 (1981-90)
The CS3 was a bookshelf/stand-mount two-way system based on the Reference Series Model 103.2.
 
Constructor Series Model CS5 (1981-90)
The CS7 was a floor-standing two-way system based on the Carlton II.
 
Constructor Series Model CS7 (1981-90)
The CS7 was a floor-standing three-way system based on the Cantata, but with the new T33 tweeter.
 
Constructor Series Model CS9 (1981-90)
The CS9 was a floor-standing three-way system based on the Reference Series Model 105.2.
 
PL301 (1985-90)
The PL301 was a constructor model featured in Elektor Electronics magazine.
 

Specification: Model CS1
System Type: Two-way bookshelf/stand-mount
Enclosure type: Closed box
Dimensions: 315 x 200 x 180mm (12.4 x 7.9 x 7.1 inches)
Nominal impedance: 8 ohms
Programme rating: 50W
Frequency response: 85Hz to 30kHz +/-3.0dB at 2m on design axis
Sensitivity: 81dB at 1m for pink noise input of 1W (anechoic conditions)
Maximum output: 98dB on programme peaks under typical listening conditions
Drive units: B110 bass unit (SP1057), T27 tweeter (SP1032)
Crossover: SP2014
 
Specification: Model CS1A
System Type: Two-way bookshelf/stand-mount
Enclosure type: Closed box
Dimensions: 315 x 200 x 180mm (12.4 x 7.9 x 7.1 inches)
Nominal impedance: 8 ohms
Programme rating: 50W
Frequency response: 85Hz to 30kHz +/-3.0dB at 2m on design axis
Sensitivity: 81dB at 1m for pink noise input of 1W (anechoic conditions)
Maximum output: 98dB on programme peaks under typical listening conditions
Drive units: B110 bass unit (SP1003), T27 tweeter (SP1032)
Crossover: SP2015
 
Specification: Model CS3
System Type: Two-way bookshelf/stand-mount
Enclosure type: Closed box
Dimensions: 520 x 280 x 210mm (20.5 x 11 x 8.25 inches)
Nominal impedance: 8 ohms
Programme rating: 75W
Frequency response: 55Hz to 20kHz +/-3.0dB at 2m on design axis
Sensitivity: 86dB at 1m for pink noise input of 1W (anechoic conditions)
Maximum output: 105dB on programme peaks under typical listening conditions
Drive units: B200 bass unit (SP1075), T33 tweeter (SP1074)
Crossover: SP2016
 
Specification: Model CS5
System Type: Two-way floor-standing
Enclosure type: Reflex/ABR
Dimensions: 700 x 280 x 310mm (27.5 x 11 x 12.2 inches)
Nominal impedance: 8 ohms
Programme rating: 100W
Frequency response: 45Hz to 20kHz +/-3.0dB at 2m on design axis
Sensitivity: 86dB at 1m for pink noise input of 1W (anechoic conditions)
Maximum output: 105dB on programme peaks under typical listening conditions
Drive units: B200 bass unit (SP1075), BD139 passive radiator (SP1082), T33 tweeter (SP1074)
Crossover: SP2016
 
Specification: Model CS7
System Type: Two-way bookshelf/stand-mount
Enclosure type: Closed box
Dimensions: 815 x 340 x 380mm (32 x 13.4 x 15 inches)
Nominal impedance: 8 ohms
Programme rating: 150W
Frequency response: 35Hz to 20kHz +/-3.0dB at 2m on design axis
Sensitivity: 87dB at 1m for pink noise input of 1W (anechoic conditions)
Maximum output: 106dB on programme peaks under typical listening conditions
Drive units: B139 bass unit (SP1044), B110 midrange unit (SP1057), T33 tweeter (SP1074)
Crossover: SP2017 and 2018
 
Specification: Model CS9
System Type: Three-way floor-standing
Enclosure type: Closed box
Dimensions: 732 x 402 x 361mm (28.8 x 15.8 x 14.2 inches)
Nominal impedance: 8 ohms
Programme rating: 200W
Frequency response: 38Hz to 20kHz +/-3.0dB at 2m on design axis
Sensitivity: 86dB at 1m for pink noise input of 1W (anechoic conditions)
Maximum output: 109dB on programme peaks under typical listening conditions
Drive units: B300 bass unit (SP1071), B110 midrange unit (SP1057), T52 tweeter (SP1072)
Crossover: SP2034 and 2035
 
Specification: PL301
System Type: Three-way floor-standing
Drive units: B300 bass unit (SP1071), B110 midrange unit (SP1057), T52 tweeter (SP1072)
Crossover: SP2066 and 2067