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Friday, January 24, 2020

How to make a 1.1 ported speaker box with 20 Watt amplifier


In this post, I have shown how to build a ported or vented 1.1 speaker box which
has one 4 ohm tweeter, one 4 inches 4-ohm woofer with DIY 20-watt amplifier with
bass/woofer & volume control.

Video

You can check the video for the construction

Theory

The main component of the speaker box is its amplifier. The amplifier is built using
the IC TDA2005 which gives an output around 20 watts. The power to the amplifier
is supplied using the transformer & regulated using the IC LM338. The
amplifier is designed in such a way that it can also accept input from an external
amplifier. The amplifier also has the option of controlling the bass or volume using
the two potentiometers.
Now coming to the speaker box, the speaker box is built using the MDF sheets.

Features of the amplifier

  • Vented or Ported Speaker
  • Volume & Bass Control
  • Can accept input from an external amplifier

Things & Components you need

  • 1 * TDA2005
  • 1 * LM338
  • 6 * 1N4007
  • 1 * 4 Ohm Speaker
  • 1 * 4 Inch 4 Ohm Woofer
  • 1 * Electrolytic Capacitor 2200uF/25V, 10uF/25V, 4.7uF/25V, 0.22uF/25v, 1000uF/25V, 2.2uF/25V
  • 3 * Electrolytic Capacitor - 100uF/50v
  • 5 * Ceramic Capacitor - 0.1uF
  • 2 * Ceramic Capacitor - 0.22uF
  • 1 * Metal Film Capacitor - 0.47nF
  • 1 * 5k Trimmer
  • 1 * 10k & 47k Normal Pot or Logarithmic Pot
  • 2 * 1k Ohm, 10 Ohm, 1.5 Ohm
  • 1 * 120 Ohm, 680 Ohm
  • 1 * Switch
  • 1 * 220v to 15-0 1 Amp transformer or 220v to 12-0 1 Amp transformer
  • Connectors like RCA, MDF Sheets & tools

Affiliate Links

Banggood
Amazon India
Amazon USA & UK
AliExpress

Making

You can create the circuit on a perf board or order a professional PCB board by
downloading the Gerber file shared at the bottom of the page. I recommend using
a professional board so you can avoid unwanted noise in the output. The Gerber file
shared was created using KiCad software which is one of the recommended CAD
software by the fabricator that I am using. The fabricator that I am using is
JLCPCB.com you can check them by Clicking Here, they provide very good quality
PCB board for a very cheap price. After you receive the board assemble the board
as shown in the video.
Once the board is assembled connect all the connectors which are necessary like
RCA Jacks, switch.
Once all the assembly is done, the first thing you need to adjust is the input
voltage. The input voltage should be around 12.5 to 14.5v. To adjust the voltage
connect two wires to the Vtp (voltage test point) on the amplifier board &
then connect the wires to the multimeter & adjust the voltage using the
trimmer RV1.

Circuit Diagram




Circuit Diagram used for fabrication




How to connect this speaker to an external amplifier

While connecting to an external amplifier make sure your speaker is not connected
to the power. The power required by the speaker is provided by the amplifier so we
do not need the speaker to be connected to the power. Now coming to the
connection, connect the output of the amplifier to the RCA Jack which says Amp
In/T Out (Amplifier In/Tweeter Out) & Amp In/SW Out (Amplifier
In/SubWoofer Out). Make sure the output of the amplifier is not too much the
speaker & woofer your using. Always check the output watts of your amplifier
before connecting it to the speaker.

How to connect this speaker to an external speaker

Connect the external speaker to the RCA Jack which says Amp In/T Out (Amplifier
In/Tweeter Out) & Amp In/SW Out (Amplifier In/SubWoofer Out)

Speaker & Amplifier Board Connection

This section of the article is only if you're using the PCB board design I shared
Potentiometer Connection
The 47K pot is for Woofer/Bass control & 10K is for volume control.




Speaker Connection
Many woofers are polarized so make sure while connecting you connect it to the
right polarity




RCA Connection
This is to connect to an external amplifier or to connect an external speaker.




Transformer Connection




Audio In Connection




Speaker Box Dimensions

Please note I am only sharing the external dimensions, so please make the joint,
connectors & speakers adjustment according to your requirement.
Front, Back, Top & Bottom
Width - 14cm, Length - 22cm & Thickness - 0.8cm
Sides
Width - 22cm, Length - 22cm & Thickness - 0.8cm

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