Showing posts with label car. Show all posts
Showing posts with label car. Show all posts
Tuesday, November 4, 2014
22Watt Car Subwoofer Amplifier
22W into 4 Ohm power amplifier, Variable Low Pass Frequency: 70 – 150Hz. This unit is intended to be connected to an existing car stereo amplifier, adding the often required extra "punch" to the music by driving a subwoofer. As very low frequencies are omnidirectional, a single amplifier is necessary to drive this dedicated loudspeaker. The power amplifier used is a good and cheap BTL (Bridge Tied Load) 13 pin IC made by Philips (now NXP Semiconductors) requiring a very low parts count and capable of delivering about 22W into a 4 Ohm load at the standard car battery voltage of 14.4V.
22 Watt Car Subwoofer Amplifier Circuit Diagram:
P1_____________10K Log Potentiometer
P2_____________22K Dual gang Linear Potentiometer
R1,R4___________1K 1/4W Resistors
R2,R3,R5,R6____10K 1/4W Resistors
R7,R8_________100K 1/4W Resistors
R9,R10,R13_____47K 1/4W Resistors
R11,R12________15K 1/4W Resistors
R14,R15,R17____47K 1/4W Resistors
R16_____________6K8 1/4W Resistor
R18_____________1K5 1/4W Resistor
C1,C2,C3,C6_____4µ7 25V Electrolytic Capacitors
C4,C5__________68nF 63V Polyester Capacitors
C7_____________33nF 63V Polyester Capacitor
C8,C9_________220µF 25V Electrolytic Capacitors
C10___________470nF 63V Polyester Capacitor
C11___________100nF 63V Polyester Capacitor
C12__________2200µF 25V Electrolytic Capacitor
D1______________LED any color and type
Q1,Q2_________BC547 45V 100mA NPN Transistors
IC1___________TL072 Dual BIFET Op-Amp
IC2_________TDA1516BQ 24W BTL Car Radio Power Amplifier IC
SW1____________DPDT toggle or slide Switch
SW2____________SPST toggle or slide Switch capable of withstanding a current of at least 3A
J1,J2__________RCA audio input sockets
SPKR___________4 Ohm Woofer or two 8 Ohm Woofers wired in parallel
The stereo signals coming from the line outputs of the car radio amplifier are mixed at the input and, after the Level Control, the signal enters the buffer IC1A and can be phase reversed by means of SW1. This control can be useful to allow the subwoofer to be in phase with the loudspeakers of the existing car radio. Then, a 12dB/octave variable frequency Low Pass filter built around IC1B, Q1 and related components follows, allowing to adjust precisely the low pass frequency from 70 to 150Hz. Q2, R17 and C9 form a simple dc voltage stabilizer for the input and filter circuitry, useful to avoid positive rail interaction from the power amplifier to low level sections.
Notes:
- IC2 must be mounted on a suitable finned heatsink
- Due to the long time constant set by R17 and C9 in the dc voltage stabilizer, the whole amplifier will become fully operative about 15 - 30 sec. after switch-on.
Output power (1KHz sinewave):
22W RMS into 4 Ohms at 14.4V supply
Sensitivity:
250mV input for full output
Frequency response:
20Hz to 70Hz -3dB with the cursor of P2 fully rotated towards R12
20Hz to 150Hz -3dB with the cursor of P2 fully rotated towards R11
Total harmonic distortion:
17W RMS: 0.5% 22W RMS: 10%
Friday, August 29, 2014
Car subwoofer filter
Circuit description:
Here is the circuit diagram of a simple subwoofer filter that can be operated from a 12V DC supply. Such a circuit is very useful in automobile subwoofer applications. The circuit is nothing but a low pass filter whose pass frequency can be adjusted between 60 to 160 Hz. The circuit is designed around the TL072 dual BIFET opamp IC. Out of the two opamps inside the chip, IC1A is wired as a buffer. The left and right audio inputs after mixing is fed to the input of the IC1A using the DPDT switch S1. Switch S1 is the phase control switch which can be used to make the subwoofer in phase with other speakers. When S1 is in position 2, 180 degree phase shift will be induced.POT R7 can be used for controlling the level. IC1B forms the low pass filter whose pass frequency can be controlled by adjusting the dual gang POT R13.
Circuit Features:
- The circuit can be powered from 12V DC.
- IC1 must be mounted on a holder.
- S1 is a DPDT switch.
- R13 should be a dual gang linear POT.
- C5 and C6 must be polyester capacitors.
- POT R13 can be used for adjusting the pass frequency.
- POT R7 can be used for adjusting the level.
Circuit diagram:
 |
| Car subwoofer filter |
Monday, August 25, 2014
TDA7384 4 x 22W car power amplifier
TDA7384 - 4 x 22W car power amplifier
I didn’t find much information about this chip on the internet so I decided to built it and try on my own. As datasheets of TDA7384 says it is low distortion, low output noise, low external component count. Also has Stand-By function and Mute function. It has several protections like from output short circuit to GND or to Vs, capable to handle very inductive loads, thermal limiter, load dump voltage. TDA7384 is an AB power amplifier cased in flexiwatt25 (eagle library is included in project archive) package wich is designed for high end car radio applications. It allows rail to rail output voltage swing with no need of boot-strap capacitors.
| Schematics TDA7384 |
I have followed the schematic in datasheed when building circuit. In datasheet you may also find PCB layout but it is two layered and didn’t fit to may box I’ve chosen. So I have made single sided PCB 50X100mm.
| PCB TDA7384 amplifier |
As I put pins on PCB for ST-BY and Mute but I not using them, I connected these pins to VCC like it is shown in PCB view. According to datasheet St-By and Mute turns off amplifier if signal in input is lower than 3.5V. So it is recommended to connect these pins to Vcc if not used.
Maximum power dissipation of chip is 80W(Tcase=70ºC), so it can handle 4 channels working at power of 20W each. But of course chip in a box doesn’t have good ventilation so I’ve put a radiator to ensure that amplifier effectively dissipates heats. I didn’t try to load amplifier to maximum to se if it doesn’t heat up to much. But at normal sound level it stays warm what is normal.
| On box amplifier |
Dont forget to put thermal paste between chip and radiator to ensure lower thermal resistance. And here we go – brand new power amplifier ready to go:
| Already to use |
source: [link]
Thursday, August 21, 2014
Simple CD Player Adapter For Car
Whenever Im in the car listening to my favourite CD, it always happens; my batteries go dead. To solve that problem, I built this extremely simple regulator schema. It steps down the 12V from the lighter socket to 9V which is used by the CD player. Different CD players (I have a Sony Discman) may require different voltages, so just use the correct regulator. All the 78xx series regulators have the same pin out, so the schema is universal.
Part Total Qty. Description
C1 1 1000uF 25V Electrolytic Capacitor
C2 1 10uF 25V Electrolytic Capacitor
C3 1 1uF 15V Elextrolytic Capacitor
C4 1 0.1uF 15V Electrolytic Capacitor
U1 1 7809 Or Other Regulator (See "Notes") See Notes
MISC 1 Cigarette Lighter Plug, Plug For CD Player (See "Notes"), Heat Sink For U1, Wire, Case.
Notes
- The voltage your CD player needs will determine which regulator you use. For 9V, use the 7809. For 6V, use the 7806. For the unlikely 5V use the 7805. Remember that whatever regulator you use, you will need to heat sink it. The metal case or metal cover on the case makes a great heat sink.
- I built the schema in a small case with the long wire to the cigarette lighter plug coming out one end, then another, slightly shorter wire going out the other end to the CD player.
- Triple check your wiring. You would hate to ruin an expensive CD player because you reversed one of the connections or hooked the regulator up backwards.
Subscribe to:
Posts (Atom)
