Project: "Unus" multimedia active speakers

This project is simpler than the "Quattuor" project. It doesn't use the LM1036 chip as audio control: it uses a simple volume control instead. As "Quattuor", it uses a pair of Visaton FR 10 4 OHM drivers. Unfortunately, those drivers are not magnetically shielded, so cautions must be taken when using them near a CRT monitor, TV or any other device containing a CRT.

The amplifier is able to deliver about 4W each channel, and has a gain per channel of 22.39dB (13.17V/V). The predicted frequency response is 60-20000Hz (-10dB).

List of components:
C1 – 4.7mF electrolytic capacitor (25V);
C2/4 – 100µF electrolytic capacitor (25V);
C3/5/10/15 – 100nF polyester capacitor (63V);
C6/11 – 2.2µF electrolytic capacitor (6.3V);
C7/12 – 33nF polyester capacitor (63V);
C8/13 – 470µF electrolytic capacitor (25V);
C9/14 – 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);
IC1/2 – TDA2003 audio power amplifier (with 10ºC/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 – 4.7K double gang potenciometer (10% tol., 1/8W);
R3/9 – 1.8K carbon resistor (5% tol., 1/8W);
R4/10 – 270Ohm carbon resistor (5% tol., 1/8W);
R5/11 – 47Ohm carbon resistor (5% tol., 1W);
R6/12 – 220Ohm carbon resistor (5% tol., 1W);
R7/13 – 2.2Ohm carbon resistor (5% tol., 1/8W);
R15/21 – 1Ohm carbon resistor (5% tol., 1/8W);
S – SPST switch.

Electrical parameters:
- Vd min = 8.80V
- Vd max = 15.72V
- Id (Vd = 13.5V) = 842.5mA
- P (Vd = 13.5V) = 11,37W

Amplification characteristics (each channel):
- Input impedance: 1.437-4.7KOhm
- Gain: 22.391dB (13.17V/V)
- Output power (Z FTE = 4Ohm): 4.7W

Audio characteristics:
- Frequency response: 60-20000Hz
- Sound pressure (SPL): 92.70dB (each channel)

Recommended enclosure specifications:
- Type: Ported (4th order Chebychev alignment)
- Volume: 6,319L
- Recommended duct: Monacor BR-30HP (length: 56mm)
- Resonant frequency (Fb): 68.494Hz (-10dB)
- -3dB frequency (F3): 59.984hz

Translations:
- Alimentação 13,5V CC - 13.5VDC supply;
- Canal direito - Right channel;
- Canal esquerdo - Left channel;
- Entrada de áudio estéreo - Stereo audio input;
- EDM - Short for left, right, ground (LRG);
- Positivo - Positive (V+);
- Secção - Section;
- Secções - Sections.

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 83mm.

These stickers are to be placed on the back of each box. "L" is for the left box (the passive) and "R" is for the right box (the active).

TDA2003 Datasheet

So where did you get your chippie?

Bill_Marsden said:

...
So where did you get your chippie?

Click to expand...

I just bought the chips from my local store.

Yeah,it seems good.

gosgirl said:

Yeah,it seems good.

Click to expand...

Thanks for your feedback, gosgirl. You might be interested in the "Quattuor" project as well.

In the attached file you can see the front and back views for both the left and right speakers. Just like the boxes for the Quattuor, the edges on the front face are meant to be beveled with a 10mm radius round bevel.