Skip to main content

DIY Portable FM Radio (Part 3) 3 Volt Amplifier

One things in mind when build a simple amplifier is by using an IC. It is very reliable and don't bother in too much complicated circuit like discrete transistor amplifier. It is not wrong, but not right either when you are planning for small 3 volt battery powered amplifier for this radio project. This IC amplifier could not working properly with this 3 volt battery.


I am using IC TBA820 amplifier. It shown in the datasheet that this minimum power requirement is 3 volt. In reality, it could not working properly and tends to distorted all the way. Sad I should remove all the circuit completely from my radio board.

I do browsing the internet and find this 3 volt circuit amplifier using only 3 transistor. It is quite simple and I can't wait to make this amplifier.

I never thought assembly this discrete amplifier is so much fun compares to the IC.

On hand I have this tiny capacitor for audio. I got this Nippon Chemicon Audio for cheap and it is looks amazing.

It is look good on this radio board.

Next step is using another board for top cover this radio. I put power switch, LED tuning indicator and the phones jack for speaker out.



I also put the 1 meter antenna at the corner side of the board.

I can tell this radio is looks stunning. This is become a bare-bone radio and I love it.



The radio reception quality is good and the sound loud enough also the clarity is acceptable. This is a very fun project.

Progress update
This battery powered radio is an evaluation project only. Although the result is considerably good, thus using battery to this kind radio circuit cannot run the radio frequency stable. It means every voltage drop in battery performance will cause the tuning reception to shift. It is become worse when the battery run bellow 80%. This is because the tuner and IC FM modulator drain so much wattage while operated, not yet counting the amp itself. So I will make an update for more simple DIY radio than this one. My planing is using small wall adapter and it should run the radio very stable yet sound good as well. Stay tune:)

Disclaimer: Any statement and photos in this article are not allowed to copy or publish without written permission from the writer. Any injury or loss from following tips in this article is not under writer responsibility.

Comments

Popular posts from this blog

OPA1622 Vs. OPA627 High Performance Op-amps Comparison

This op-amps comparison topic is actually boring, but at the same time, many of us still curious about what others think about it. The reason is simply because of the op-amps variation are hundreds and they are depends by the implementation. The op-amps are considerably cheap and an interchangeable electronic components but they are not built for the same function. So in this discussion, I will focus on the modern Vs. vintage high performance op-amps in the simple non-inverting pre-amplifier gain stage.

Vintage Multibit R2R DAC Tier List

At the very beginning of this year, I committed to explore the best multi-bit R2R DAC. This is simply because I have plenty of the resources (from broken old unit CD player of course) and ability to build them up. If you think this kind a recycle from old un-used unit to become something useful, than I should stated myself giving contribute for greener world:) After all DAC that I built in this year, I think it is better for me to list them up again in one single page like this. Then I will rank them up in a simple tier list. The reason for this, so you all know what my opinion about of those vintage multibit R2R DAC especially in the sound quality.

PCM56 R2R Non Oversampling DAC Built

From early this year, I am start to playing a lot with the multibit DAC. They are from Sony CDP TDA1541A here , Nakamichi DAC-101 dual TDA1541S1 here , Clarion DRX-9255EXL PCM1702 here  and Clarion HX-D1 PCM1704 here . What I said playing with them is actually more suitable words because none of them are built by myself. I only study and exploring those unit then make some upgrade especially on the power supply components, signal capacitors upgrade, and bypassing the unused internal circuit for more clearer yet natural sound quality. This upgrade make a lot improvement compare to the first time I listen from it and I can really enjoy what the designer from each manufacture deliver the sound they would like to perform in those units. Those said units are categorized as a parts of hi-end audio system and I really now familiar with the sound signature from each of them. But to be honest, I am not satisfy yet with this condition. Because none of them is built by myself from ground up. ...