5

Typical Performance Curves

FIGURE 1. THD +N (%) vs FREQUENCY LOAD = 8

Ω

FIGURE 2. AMPLIFIER FREQUENCY RESPONSE

10W - LOAD = 8

Ω

FIGURE 3. AMPLIFIER TRANSFER CHARACTERISTIC WITH

VARIOUS SETTINGS OF SOFT CLIPPING

RESISTOR

FIGURE 4. OSCILLOSCOPE DISPLAY OF AMPLIFIER

OUTPUT WITH SOFT CLIPPING CIRCUIT

ENABLED

Soft Clipping

Figures 3, 4 and 5 show the effects of the soft clipping

circuitry within the amplifier. Figure 3 shows the transfer

characteristic of the amplifier for various values of the soft

clipping programming resistor. An important aspect of soft

clipping is the apparent increase in sound level. As soft

clipping is reached, the upper and lower envelop of the

sinewave is gradually reduced. This “soft” rounding reduces

the higher harmonics that would result if hard clipping as

shown in Figure 5 was enabled. Soft clipping also results in

an amplifier with a more pleasing sound. Figure 4 shows the

rounding of the output with soft clipping, while Figure 5

shows the ampler output without soft clipping.

FIGURE 5. OSCILLOSCOPE DISPLAY OF AMPLIFIER

OUTPUT WITH SOFT CLIPPING CIRCUIT

DISABLED

1

0.1

0.01

0.001

0.0005

10

100

1k

10k

30k

FREQUENCY (Hz)

400W

20W

10

100

1k

10k

80k

FREQUENCY (Hz)

1.000

0.0

-1.000

-2.000

-3.000

-4.000

-5.000

-6.000

LOAD = 4

Ω

LOAD = 8

Ω

0.0

13.0

26.0

39

52

65

78

90

0.0

0.6 0.12 0.18 2.4

3.0

3.6

4.2

4.8

5.2

6.0

1012

760

528

338

190

84

21

0.0

LOAD = 8

Ω

AMPLIFIER OUTPUT vs INPUT

R = 20K

R = 10K

R=

∞

1ms/DIV

DSA 602A DIGITIZING SIGNAL ANALYZER

1ms/DIV

DSA 602A DIGITIZING SIGNAL ANALYZER

HCA600ACREF