Service Section

New Zealand Listener, Volume 31, Issue 796, 22 October 1954, Page 15

Service Section

Readers with special problems in the care and maintenance of radio receiving sets are invited to send inquiries to the Editor of "The Listener."

Names and addresses are required. Wherever possible, replies will be given, either in "The Listener" or by letter. ~

PATRICK DAVEY (New Plymouth) intends to buy a radio chassis (five or six-valve broadcast), 12-inch speaker and Garrand three-speed automatic change record player, and to make his own radiogram. He asks if the above components are suitable for first-class reproduction, if they are the most economical, and if there are any special points to be watched while assembling them in a simple cabinet. A radiogram built up with the com-: ponents described should provide quite good quality reproduction at a reasonable cost. The following points may be helpful: (1) The speaker transformer must be correctly matched to the output stage of the receiver. (2) Ensure that the receiver is capable of providing sufficient volume when used with the pick-up selected. Crystal pick-ups have a fairly high output, and will generally work satisfactorily with a five or sixvalve broadcast set. This may be an important consideration if long-playing records are to be used. (3) The receiver should have adequate ventilation. It should be mentioned that to obtain the best quality of reproduction it is necessary to employ audio ‘amplifiers designed specifically for sound reproduction systems. These amplifiers, of which there are several makes on the market, are as a rule more expensive than the five or six-valve broadcast receivers which the correspondent proposes to use. * Es * J.M.K. (Wallacetown) is having difficulty in isolating stations. "I have been trying to pick. up a programme from 4YC, but have been unable to isolate it from interference on either side of the wave-band. Now I have turned over to 3YZ at Greymouth, and the Strauss opera is coming over perfectly." A receiver in good condition should be sufficiently selective to prevent interference between stations, providing they .are not too close in frequency. In Southland, 4YC, quite unavoidably, will suffer from fading, especially at night. When it facies, the correspondent may be hearing an Australian station opetating on the same frequency as 4YC. ;