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HAC model K. 1 Valve Receiver




The HAC model K 1 Valve Receiver. The valve is an 1T4 (DF91) and dates from the late 1940's. The instruction sheet has been cleaned up by me and where required component numbers and values added.
Also included in the instructions is a 2 valve amplifier kit which was availiable from HAC. The pictures below show a chassis made for me by Nigel Claricoats which also has a hole cut out for an octal valve holder. Hence different models of the HAC receivers can be built.


HAC model K Chassis

Instruction sheet and Circuit. Page 1 Instruction sheet and Amplifier Circuit. Page 2



The following pictures outline the construction of a model K. The receiver was built firstly to connect to a transistor amplifier and lastly modified for headphone use.
The set has proved lively after dark. And there is no problem picking up Europe/Africa and the Americas (in Kent).
When using the receiver as a tuner for an amplifier the headphones were replaced by a 4k ohm resistor and a 0.1uf capacitor connected to the anode of the 1T4 valve. There are also two pictures of the chassis fitted with a jack socket and driving headphones from S G Brown Type F and a pair of Ericsson of Batley Yorkshire.Both types have 4k ohm coils fitted (ie 2 x 2k).
It has been found possible to receive stations with an HT voltage of less than 35 volts.
See also the HAC DX page for another model K built by John (G4JGG)    HAC DX.



Chassis mechanical Layout Chassis Rear
Under Chassis
Model K with S G Brown Headphones Model K with Ericsson Headphones

HAC Tuning Scale Replica
HAC. Paper Tuning Scale Replica


HAC replica Chassis. This drawing was produced by Tim Cristian who ran Isoplethics, a company in Norfolk specialising in reviving long out of production components and Coils,RF Chokes etc.
Unfortunately Tim became ill late in 2006 with Pancreatic cancer and was forced to close his firm down after many years of serving the amature. Sadly Tim died in April 2007.This chassis drawing was done for me by Tim who also supplied the chassis shown above.
Elsewhere on the site is another chassis drawn by Tim for a design by Practical Wireless in the 1960's.
HAC Experimental Chassis Drawing






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Last updated 17.11.2008


2003-2008 © Maurice Woodhead