Laboratory Jottings

Radio Record, Volume IV, Issue 5, 15 August 1930, Page 27

Laboratory Jottings

Audak Pick-up.

MESSRS. Bond and Bond, Auckland, have supplied us with an Audak pickup of the type used for the home,’ which has proved to be a first-clasg article from all points of view. © Our tests were taken from the angles of 1. Signal response or the "loudness." 2. Frequency response or the "range," 8. Quality or pureness of the output, 4, Effect on records. Comparisons were made with a standard pickup by arranging’both so that they could be played on the same record simultaneously. By a switch’ the output of either could be fed into the amplifier and so a comparison made. In the first place the Audak showed that under the same conditions as a standard instrument it was capable of giving a greater signal output; in other words, it was considerably louder. Tests on several grades of -needles showed this characteristic to persist. . The range covered, with equal intensity over a large portion, was from below 40 cycles to over 9000... The signal strength even at the extremes. was considerable and the instrument continued to respond after the standard had ceased. With a coverage such as this it is not surprising that the quality of the pickup is outstanding. There is colour and brilliance that is quite unusual. Notes at both extremes of the scale are distinct, crisp and clear. -A complete absence of slurring, jar or "tinniness" imparts splendid quality to this instrument. _ Although a properly adjusted pickup is not hard on records, these instruments are usually not infallible and slightly incorrect adjustment is liable to damage records. There are two problems-the weight of the pickup must be such that the head will remain in the grooves of deep notes, and the lightness must be such the records will not be torn. This means a compromise and the Audak has struck the happy medium. With the pickup adjusted as earefully as possible a record was played and the needle (fine) examined under a microscope. The residual dust was then compared with the usual de posit on the needles of pickups and proved to be less than usual. It tracks over notes below 50 cycles smoothly and that is not an easy feat. Fibre needles, provided their shanks are trimmed to fit the needle aperture, work well with this instrument. We found, using the Loftin White amplifier, that they would give comfortable strength on most records and-.a ree serve on some of the louder ones. By using these needles the records can be indefinitely preserved. A separate volume control is employed. It can be detached from the pickup and used between the aerial and, the set as a control for the radio receiver,