The Quatour project
Here is a project of mine that I've posted on the All About Circuits website forum. But why not post it here anyway.
Thia project is nothing fancy. It is meant to be a medium fidelity multimedia speaker system, a "cheapo". The amplifier is able to deliver 4W each channel, and has a distributed gain per channel of 22.22dB (12.91V/V). However, when the balance control is taken to one of its extremes, the channel has an effective gain of 23.80dB (15.50V/V). The predicted frequency response is 68-15000Hz. The speakers are the worst part. They are not magnetically shielded, and they require a box that makes them sound boomy, resulting in non-detailed bass. On Quatour II, there and more problems will be solved. If you intend to build this project, DON'T USE IT NEAR ANY CRT MONITORS. The enclosure may not big enough to "cover up" some exposed magnetic field. MDF doesn't shield magnetic fields.
List of components:
C1 – 4.7mF electrolytic capacitor (25V);
C2/12/21 - 10nF polyester capacitor (63V);
C3/4/18/27 – 100nF polyester capacitor (63V);
C5-8 – 220nF polyester capacitor (63V);
C9 – 47µF electrolytic capacitor (25V);
C10/19 – 10µF electrolytic capacitor (25V);
C11/20 – 330nF polyester capacitor (63V);
C13/22 - 470nF polyester capacitor (63V);
C14/23 – 2.2µF electrolytic capacitor (6.3V);
C15/24 – 150nF polyester capacitor (63V);
C5-8 – 220nF polyester capacitor (63V);
C16/25 – 470µF electrolytic capacitor (25V);
C17/26 – 1mF electrolytic capacitor (25V);
D1 – 1N5400 rectifier diode;
D2 - Red LED (GaAsP/GaP)
FTE1/2 – Full-range speaker Visaton FR 10 4 OHM;
HS1/2 - 10ºC/W passive heatsink (for TO-220);
IC1 – LM1036 audio control;
IC2/3 – TDA2003 audio power amplifier (with 9.1ºC/W heatsink);
J1 - 5.5mm x 2.1mm DC socket;
J2 - 3.5mm TRS socket (stereo phone socket);
J3/4- RCA socket;
JW - 26AWG stranded wire;
R1 – 680Ohm carbon resistor (5% tol., 1/2W);
R2/4/6/8 – 47K potenciometer (10% tol., 1/8W);
R3/5/7/9 – 47K carbon resistor (5% tol., 1/8W);
R10/15 – 1,2K carbon resistor (5% tol., 1/8W);
R11/16 – 100Ohm carbon resistor (5% tol., 1/2W);
R12/17 – 56Ohm wirewound resistor (5% tol., 3W);
R13/18 – 4.7Ohm carbon resistor (5% tol., 1/4W);
R14/19 – 1Ohm carbon resistor (5% tol., 1/8W);
S – SPST switch.
Electrical parameters:
- Vd min = 9.80V
- Vd max = 15.72V
- Id (Vd = 13.5V) = 1,349A
- P (Vd = 13.5V) = 18,21W
Amplification characteristics (each channel):
- Gain (pot R4 centered): 22,22dB (12,91V/V)
- Gain (pot R4 all to left or all to right): 23,80dB (15,50V/V)
- Output power (Z FTE = 4Ohm): 4W
Audio characteristics:
- Frequency response: 68-15000Hz
Translations:
- Agudos - Trebble;
- Alimentação 13,5V CC - 13.5VDC supply;
- Balanço - Balance;
- Canal direito - Right channel;
- Canal esquerdo - Left channel;
- Entrada de áudio estéreo - Stereo audio input;
- EDM - Short for left, right, ground (LRG);
- Graves - Bass;
- Positivo - Positive (V+);
- Secção - Section;
- Secções - Sections;
- Volume - Volume (no translation here).
Important: When printing the PCB and the panel prints, print them in real size. This is a requirement, even if you print in A4. Some printers will reduce to fit. This procedure should work for both A4 and Ansi A (8.5" x 11") formats. The PCB should measure 120mm x 118mm.
I will post the enclosure plans as soon as I finish them.
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