Questions and Answers

Radio Record, 8 April 1938, Page 65

Questions and Answers

‘"H)NTHUSIAST" (Nelson): We are very glad to hear that your efforts with the "Junior Allwaver" are being crowned With such success. If you are obtaining a new H.T. supply it might be worth while getting the 120-volt size and using only 90 on the 1G5G. Do not use any more than 90 on this valve, even with a correspondingly higher bias it will not improve the output other than increasing the milliwattage, and what output there is at present is sufficient. Of course, you could obtain a 90-volt unit and gain the extra volts for the R.F. valve from an added dry B battery which would last a long time due to its low drain. Your question regarding the "bouster" is rather indefinite as you ask whether the suggested arrangement would be better than the original, which you have not described. However, the suggested arrangement looks as though it would operate satisfactorily and it is at least worth a trial. We will be pleased to receive your list of stations received as soon as you have it complete. ‘o M." (Palmerston North): Your ° questions though brief would require several pages of this issue to answer. For economy the five-pin penfode valves in the output stage would be better than the four-pin — triades. Elsewhere four-pin types will do very well, Use pentodes such as 1A4, 1B4, et«.. in R.F. stage, ete. bees The circuits are many and various in their operation, and the choice of a

particular one depends on other fac tors than the available speaker and eliminator. It would pay you to look through back numbers of the "Radio Times" and make a choice from the many circuits shown there. We cannot design circuits for readers for special requirements, and Only send postal replies when the fee of 1/- accompanies