(Details shown apply to the default selection)
RIAA equalisation is a form of pre-emphasis on recording and de-emphasis on playback. A recording is made with the low frequencies reduced and the high frequencies boosted, and on playback the opposite occurs. The net result is a flat frequency response, but withattenuation of high frequency noise such as hiss and clicks that arise from the recording medium. Reducing the low frequencies also limits the excursions the cutter needs to make when cutting a groove. Groove width is thus reduced, allowing more grooves to fit into a given surface area, permitting longer recording times. This also reduces physical stresses on the stylus which might otherwise cause distortion or groove damage during playback.
A potential drawback of the system is that rumble from the playback turntable's drive mechanism is amplified by the low frequency boost that occurs on playback. Players must therefore be designed to limit rumble, more so than if RIAA equalization did not occur.
RIAA equalization is not a simple low-pass filter. It defines transition points in three places: 75 µs, 318 µs and 3180 µs, which correspond to 2122 Hz, 500 Hz and 50 Hz (rounded values). Implementing this characteristic is not especially difficult, but is more involved than a simple amplifier. In the past, almost all hi-fi preamplifiers, integrated amplifiers, and receivers had a built-in phono preamplifier with the RIAA characteristic, but it is often omitted in modern designs, due to the gradual obsolescence of vinyl records. Add-on phono preamplifiers with the RIAA equalization curve are available; these adapt a magnetic phono cartridge to an unbalanced −10 dB consumer line-level RCA input. Some modern turntables feature built-in preamplification to the RIAA standard. Special preamplifiers are also available for the various equalization curves used on pre-1954 records.
Be the first to Write a Review for this item!
Customers who bought this item also bought:
Pro-ject Phono Box DS£229.00 £175.00
Pro-ject Tube Box S MM and MC Phono Stage£309.00
Home > Hi Fi > Phono Stages & Phono Boards > Project Phono Stages