Audio Engineering

170 Chapter 7

LP records are produced, in conformity with the Recording Industry Association of
America (RIAA) recording standards. The preamplifi er will then be required to have a
gain/frequency characteristic of the form shown in Figure 7.3(b) , with the deemphasis
time constants of 3180, 318, and 75 μ s, as indicated in the fi gure.

The output levels produced by such PU cartridges will be of the order of 0.8–2 mV/cm/s
of groove modulation velocity, giving typical mean outputs in the range of 3–10 mV at
1 kHz.

7.3.3 Moving Coil Pick-Up Cartridges

These low-impedance, low-output PU cartridges have been manufactured and used
without particular comment for very many years. They have come into considerable
prominence in the past decade because of their superior transient characteristics and
dynamic range as the choice of those audiophiles who seek the ultimate in sound quality,
even though their tracking characteristics are often less good than is normal for MM and
variable reluctance types.

50 100 200 300 500 1 K

Frequency

2K 3K 5K 10K

(Replay)

(b)

(75μs)

(318μs)

(3180μs)

Output (dB)

 20

 17

 3

 3

 17

 20

(a)

0

(Record)

2121.5 Hz

21.21 kHz

500.5 Hz

50.05 Hz

1 kHz

30 20 KHz

Figure 7.3 : The RIAA record/replay characteristics used for 33/45 rpm vinyl discs.