Laboratory Jottings

Radio Record, Volume IV, Issue 21, 5 December 1930, Page 11

Laboratory Jottings

Marconiphone Pickup HOSE who want a pickup that is medium in price, light on records and yet which reproduces well will be interested in the new Marconiphone instrument, for which A.W.A. are the’ New Zealand wholesalers. This instrument has the bent tone-arm, the principle of which was described in these columns some months back, By utilising this shape the track angle error ig reduced to 3 degrees, with the consequence that there is a minimum of wear. While on test it was found that the friction between record and needle was much less than the standard, and without any trouble it tracked over grooves representing a note of 42 cycles a second. This is unusual. Furthermore the head, which is swivelled on the tone-arm, is light and the tone-arm counterbalanced Further evidence that the instrument is constructed to wear records at a minimum rate is provided by the movement of the needle in the armature, which is far greater than normal, . The voltage output (14 volts R.M.S.) is high, with the result that streng signals can be had with an averaze set of, say, two valves. Its output is about equal to that of high-grade instruments. The tone is good, and giving empha- | sis to the bass notes is excellent for amplifiers that tend to clip this end of the scale. One measured bass reproduction tdéok us down to 40 cycles, there being practically equal amplification between here and 4000 cycles. After this there is a decline until at about 5000 there is, a sharp cut off. Thus the instrument tends to emphasise the bass without unduly thinning down the treble, and gcratch cannot come through to any extent. There is an absence of peaks, and amplification is equal between the points mentioned.