This is an ambitious project, but still accessible for beginners. This particular project uses the LM1036 chip as audio control (volume, balance, bass and trebble) and uses a pair Visaton FR 10 4 OHM full-range drivers. These drivers have a good sound quality, but unfortunately they 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 distributed gain per channel of 22.21dB (12.89V/V). However, when the balance control is taken to one of its extremes, the channel has an effective gain of 23.79dB (15.47V/V). The predicted frequency response is 60-20000Hz (-10dB).

List of components:
C1 – 4.7mF electrolytic capacitor (25V);
C2/14/23 - 10nF polyester capacitor (63V);
C3/4 - 100mF electrolytic capacitor (25V);
C5/6/20/29 – 100nF polyester capacitor (63V);
C7-10 – 220nF polyester capacitor (63V);
C11 – 47µF electrolytic capacitor (25V);
C12/21 – 10µF electrolytic capacitor (25V);
C13/22 – 330nF polyester capacitor (63V);
C15/24 - 470nF polyester capacitor (63V);
C16/25 – 2.2µF electrolytic capacitor (6.3V);
C17/26 – 33nF polyester capacitor (63V);
C18/27 – 470µF electrolytic capacitor (25V);
C19/28 – 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 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);
R2/4/6/8 – 47K potenciometer (10% tol., 1/8W);
R3/5/7/9 – 47K carbon resistor (5% tol., 1/8W);
R10/17 – 1K carbon resistor (5% tol., 1/8W);
R11/18 – 2.7K carbon resistor (5% tol., 1/8W);
R12/19 – 390Ohm carbon resistor (5% tol., 1W);
R13/20 – 47Ohm carbon resistor (5% tol., 1W);
R14/21 – 220Ohm carbon resistor (5% tol., 1W);
R15/22 – 2.2Ohm carbon resistor (5% tol., 1/8W);
R16/23 – 1Ohm carbon resistor (5% tol., 1/8W);
S – SPST switch.

Electrical parameters:
- Vd min = 9.80V
- Vd max = 15.72V
- Id (Vd = 13.5V) = 887.5mA
- P (Vd = 13.5V) = 11,98W

Amplification characteristics (each channel):
- Input impedance: 967.7Ohm
- Gain (pot R4 centered): 22.10dB (12.75V/V)
- Gain (pot R4 all to left or all to right): 23.69dB (15.29V/V)
- Output power (Z FTE = 4Ohm): 4.7W

Audio characteristics:
- Frequency response: 60-20000Hz (-10dB)
- 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
- -3dB frequency (F3): 59.984hz

Translations:
- Agudos - Treble;
- 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 131mm.

 

Circuit diagram is now available in PDF format. Soon I will make available the PCB and the box project.

 

Hi Cum,
It is in a foreign language. Spanish?

 

Looks more like Portuguese than Spanish... And Cumesoftware is on record as posting from Portugal.

Is "esquerdo" left and "dereito" right? Or the other way around?

 

Hi Cum,
It is in a foreign language. Spanish?

Looks more like Portuguese than Spanish... And Cumesoftware is on record as posting from Portugal.
...

It is Portuguese, indeed.

...
Is "esquerdo" left and "dereito" right? Or the other way around?

"esquerdo" means left and "direito" means right. Sorry about my old habit of writing my projects in Portuguese, but I'm in the hope that my Portuguese audience pays attention (and, it also makes sense that I save my own projects in my native language). I'll post some translations for you.

 

The symbols are standard and it takes a little thinking, but I'm sure most will figure out the circuit. At least the numerals don't change between languages, it's still base 10.

 

The symbols are standard and it takes a little thinking, but I'm sure most will figure out the circuit. At least the numerals don't change between languages, it's still base 10.

Portuguese have 5 fingers on each hand, just like every human. No wonder it is base 10. But the numerals could be base 16 and you wouldn't even notice it!

About the symbols: the diagram uses European symbols, which are different from the ones used in USA.

 

Americans have only 4 fingers on each hand. Their 5th fingers were shot off because of their obsession with guns.
Many Canadians lost their 5th fingers to hungry Polar Bears.
Brits are missing their middle fingers.
People who are "down Under" are missing their middle toes.

 

Nonsense. I've only shot off three of my toes, none of my fingers. And that was with a foreign made firearm!

 

Americans have only 4 fingers on each hand. Their 5th fingers were shot off because of their obsession with guns.
...

It seems that Americans have to stick with the octal base. No wonder why octal was invented!

 

The PCB layout is finally available for download. I had to upload the circuit diagram again, since I uploaded the wrong version. The circuit should be supplied with 13.5VDC and not with 12VDC.

 

I'm very interested in how you drew that schematic, where is Visio to be found? Thanks.

 

I seen various versions of visio for sale at ebay.

I don't know if the newer versions have the technical stencils.

 

I'm very interested in how you drew that schematic, where is Visio to be found? Thanks.

If you haven't bought it yet, don't but it. I will give you three reasons why you should not:
- It is expensive, and you are funding Micro$oft, that non-profit organization that we all know (I committed that mistake multiple times, but I won't buy even one broken CD from M$ in the future);
- There are more appropriate, free alternatives, like FreePCB;
- You probably need to learn how to handle Visio, so it is better to start learning with the alternative instead.

I used Visio because I didn't felt comfortable using other tools. It was very hard to do that PCB, believe me. It is the last I'm doing that way. Meanwhile, I'm looking for free and fully functional PCB tracers.

By the way, I uploaded the PCB again. It had to be cut to fit in the enclosure.

 

The prints for the panels are available in PDF format. The first print is for the back of the left box, the second is for the front of the right box and the last one is for the back of the previous.

 

I know that I'm always promising that it will be the last time I will upload the PCB. After checking the lack of safety of the pots, I had to redraw the PCB, hopefully for the last time. I added some extra space for the bracket so if will fix the pots even better.

 

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).

 

Will the stickers help the tiny speakers produce some bass sounds??

 

Will the stickers help the tiny speakers produce some bass sounds??

No. For that we have the enclosures.

However, they sure will help users in the act of not suing me!

 

Hi

I think the "Quatour" is more like what I need, thanks. A bit of tone control etc. will do the job very nicely. I will buy decent speakers to match.

I see the project requires 13.5V, will this be an issue if I supply 12V? I can use 2X12V Gelled Cells and regulate the voltage but would prefer not to.


Cheers
Andrew