Wednesday, March 30, 2016

Tone Control + Subwoofer Filter

PT2350 is a tone control subwoofer cross-over low pass filter chip utilizing CMOS Technology. It features a tone control range of + 10dB (50Hz, 4 KHz) and subwoofer low pass filter of the second order Sallen Key Design. The roll-off point can be adjusted by changing the value of the external capacitor. Pin assignments and application circuits are optimized for easy PCB Layout and cost saving advantages.

tone control subwoofer


CMOS Technology

2-Channel Input
3-Channel Output (Including 1 stereo Output and Subwoofer Output)
Low Total Harmonic Distortion (THD<0.01%, Subwoofer THD<0.2%)
High S/N Ratio (S/N Ratio <-87dB, A-weighting)
Least External Components
Adjustment of Frequency response by changing the value of the external component
Single Power Supply: 3 to 8.5 Volts
Available in 20 pins, DIP or SO Package

PARTS
Resistors
2------ R1,R2-------------- --------- 10k / 1% / metal film
Capacitors
2------ C9,C10------------- -------- 4.7nF / 63V / polyester / raster R. 5mm
3------ C1,C7,C8-------- ----------- 47nF / 63V / polyester / raster R. 5mm
1------ C16---------------- --------- 100nF / 63V / polyester / raster R. 5mm
1------ C13----------------- -------- 220nF / 63V / polyester / raster R. 5mm
2------ C3,C4------------- --------- 2.2uF / 50V / polyester / raster R. 5mm
5------ C5,C6,C11,C14,C15--- 3.3uF / 100V / electrolytic / vertical / raster R. 5mm
1------ C12-------------------------- 10uF / 35V / 105C / electrolytic / vertical / raster R. 5mm
1------ C17----------------- --------- 100uF / 16V / 105C / electrolytic / vertical / raster R. 5mm
1------ C2---------------------------- 470uF / 35V / electrolytic / vertical / raster R. 5mm
Integrated Circuits
1------ U1---------------------------- 78L08 / +8V voltage regulator / TO-92
1-------U2---------------------------- PT2350 / stereo tone control, subwoofer low pass filter IC / DIP20
Diodes
1------ D1---------------------------- 1N4153
Miscellaneous
1------ J1----------------------------- 2 pole wire connector (terminal block) to pcb / raster r. 5 mm / hight 9.7 mm
1------ P1----------------- ----------- 10k log stereo potentiometer / 6 mm saft
2------ P2,P3------------------------ 100k lin stereo potentiometer / 6 mm saft
5------ J2 to J5---------------------- RCA female to PCB, straight, Hosiden any colour

NOTICE ABOUT J2 to J18 . if you make one stereo input device you need 5 pcs of RCA female as listed in parts list
If you make 2 x 6 input device, you need total quantity of 15 pcs RCA female and also 2 x 6 changeover switch.
Code of J2 to J18 RCA female to PCB, straight, Hosiden, any colour
SW1 2 x 6 changeover High quality DIP rotary switch to PCB 2 x 6, Alcos witch DRS 2-6, 3.2mm saft

Frequency response of tone control unit is flat between 20 Hz … 20 kHz when treble and bass pots are in middle.
Overall gain is approx. 6 dB when treble and bass pots are in middle.
Treble and bass tone control range is approx. 10 dB (50Hz / 4 kHz) with given component values.
Subwoofer cut off frequency can be adjusted by bass potentiometer… with component values as listed above it is as follows : bass pot in minimum (left) -3dB point, 240 Hz / -12dB 450 Hz, bass pot (middle) -3dB point 100 Hz /-12dB 200 Hz, bass pot maximum (right) -3dB point 60 Hz / -12dB 120 Hz.
Distortion was < 0.1 % when input level was < 0.3V rms.
There is no balance adjustment potentiometer in this application, if you need balance, you must add it separately in this device.

Electronic Circuit is a good site for hobbyist also who would like to try DIY because it shared good circuits. If you have a personalized circuit requirement you may feel free to request it through the comment box or contact me.


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