CXA1946BQ/BR
4. Tone control
The configuration of the tone control circuit is shown in Fig. 4. CTCLCX2 and CTCHCX are connected
externally, and the tone control frequency characteristics can be changed by changing these constants.
The relationships between CTCLCX2/CTCHCX and the frequency characteristics are as follows:
1/fL = 2πCTCLCX2 (R3//R4)
1/fH = 2πCTCHCXR5
The maximum bass boost and cut can be made smaller than in the Application Circuit by connecting an
external resistance to the TCLCX1 pin in series, or else connecting an external resistance to CTCLCX2 in
parallel. (See Fig. 5.) Furthermore, the maximum treble boost and cut can be made smaller than in the
Application Circuit by connecting an external resistance to CTCHCX in series. (See Fig. 6.) However, when
these methods are used, variations in the absolute value of the CXA1946B internal resistance (±20% max.)
and in the external resistance will cause variations in the tone control characteristics. Set these constants
after studying all considerations carefully. Note that when the method illustrated in the Application Circuit is
used, variations in the internal resistance of the CXA1946B have no effect on the tone control
characteristics.
The input impedance is 19kΩ (typ.) for TIN1 and TIN2.
The output impedance for TCO1 and TCO2 is low impedance (roughly 0Ω). The tone step width and gain
are not affected by the load impedance.
CTCLCX2
0.39µ
TCLCX1
TCLCX2
12k
TINX
TCOX
R4
8k
input impedance
14.1k
CUT
14.1k
14.1k
BASS
19kΩ
ON
12k
OFF
R3
8k
ON
OFF
BOOST
10k
10k
CUT
10k
ON
OFF
fL
fH
R5
5k
10k
ON
14.1k
Tone control frequency
characteristics
OFF
TREBLE
BOOST
TCHCX
CTCHCX
0.0027µ
Fig. 4. Tone Control
– 19 –
SONY [ SONY CORPORATION ]
