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'IM' long-playing thorn needles and BCN needle sharpener.
The gramophone enthusiast of long standing with a large library of valuable records will generally be found to show a strong partiality for fibre needles. Experience shows that the technical objections to the use of these needles are out weighted more often than not by their practical advantages. This is unquestionably the case where the needle point reaction of the pick-up is high, for the fibre needle acts as an effective buffer and prevents damage to the wall of the groove. Surface noise and mechanical noise from the pick-up are also much less with fibre than with steel needles.
The 'IM' long-playing needles produced by Alfred Imhof, Ltd., 112-116, New Oxford Street, London, WC1 are made from the thorns of the South African prickly pear plant and are hard enough to withstand the wear of eight consecutive records (the usual number in automatic record-changing units) after which they can be repainted an used for at least 50 playings.
Our tests confirmed the claims for low surface and mechanical noise, and also showed that the reduction in output at the high frequencies by comparison with steel needles was much less than usual. Taking the output from a 'permanent' steel needle as standard a uniform reduction of level of 6 dB was recorded with the 'IM' needle up to 3 kHz. At 6 kHz the output voltage was down a further 2 dB, at 7 kHz 6 dB, and at 8 kHz 11 dB. After playing two sides of a 12 in record no measurable falling off in output could be detected up to 3 kHz, and the wear produced a reduction of 2 dB at 5 kHz and 3 dB at 8 kHz. There is a visible flat on the point after eight playings, but this is easily removed by the sharpening tool.
The needles are attractively packed and a box of ten costs 2/-.
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