LFD AUDIO: Q/A with Dr. Bews. The correct operation of the LE Phonostage

Correct operation of the LFD Phonostage LE

The prime function of the LFD Phonostage LE is the amplification and equalisation of the electrical output from Moving Magnet and High Output Moving coil cartridges. To use the phonostage, just simply plug in the input, output and mains cables into the rear sockets, as described in figure 1. It is advisable to position the phonostage remotely from other mains powered equipment to reduce the possibility of induced hum, minimum recommended distance apart 0.5m.

Interconnect cable runs up to 2m-3m can be tolerate, however it is recommended that these Interconnects be as short as possible to reduce the sound degradation present within some cables.

Input loading

The LFD Phonostage LE has a fixed standard input impedance of approximately 47kohm, which suits the majority of Moving magnet and High Output Moving Coil cartridges available. Although altering the load impedance seen by a cartridge changes the sound quality to some extent, the quality of the resistor employed is far more important. Subjective evaluation has established that the added complexity caused by switching in differing resistor values to define the input impedance, produces an unacceptable level of signal degradation, which therefore dictates that a fixed input impedance is the only option offered.

Gain Change

The gain of the Phonostage is factory set for High Output Moving coil cartridges. However, if a Moving Magnet cartridge is used, the gain can be decreased for each channel, by de-soldering a link across the pins on the Printed Circuit Board close to the 8 pin IC.

Running-in Period

The LFD Phonostage LE does required a short running-in period after purchase, around 7-14 days use is sufficient. After this period, the phonostage will sound more focused and posses a less fuzzy sound compared to a brand new Amplifier. Also, all LFD phonostages should be left permanently switched on, so as to keep them at their optimum working conditions.

Dr Richard Bews

ME but smaller

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