Monday, 14 May 2018

Upcyling / Recycling an Old Stereo Amplifier

Upcyling / Recycling an Old Stereo Amplifier - Chapter 1 - Intro


I am not overly interested in electronics I find it fiddly and not very satisfying. However, to me throwing a large complicated piece of electronic equipment in the bin is a literally a crime. . .  or it soon will be. E Waste in Ghana



For someone with low skills such as myself the percentage of what can be upcycled / reused is fairly low. But it saves some waste at least. It may also save you some money, by re-using the case, power supply and connectors you are perhaps saving £50 / $100 on a DIY build. . . . . . I hope to complete this project for about £20 / $40. Bear in mind you can buy a cheaper amplifier for £30! But where is the fun / satisfaction in that I ask. . . . .

Watch Chapter 1 You Tube Video on Upcycling an Amplifier. 

I should point out that my first attempt at this build went horribly wrong. I did not understand the power supply and some of the other wiring. I fried all of my new circuits! So more rubbish for the scrap heap! So you know where you stand perhaps use a modern switching power supply. . . but then our goal to prevent waste is very much reduced. I am only really reusing the case, and a few connectors. Hardly worth the effort. 

Upcyling / Recycling an Old Stereo Amplifier - Chapter 1- What You Need


A minimum kit list of attempting this project is:


  • Voltmeter / Multi-meter
  • Soldering Iron
  • Screw Driver 
  • Wire
  • Replacement Circuit Board with Suitable Voltage


Upcyling / Recycling an Old Stereo Amplifier - Chapter 1 - Whats Inside?


The below amplifier is an old friend I bought this when I was 18 (over 20 yeas ago) and it has been used for countless parties, outdoor raves (linked with friends amplifiers), run on generators, used as a seat at bus stops. . . . . hence dent in lid! But alas it no longer works, and having checked the side I found the circuit board had a large crack running through it, and some of the leg have been torn from one of the large Class A Amplifiers.

WARNING: On the back of you amplifier there will likely be a message saying "Danger of Death" or "Risk of Electric Shock". This is there because there are bits inside that will kill you if you touch them. So if you do take the lid off you amplifier, that is what might happen. I am just explaining what I did. Only copy me if YOU choose to do so. 




So next I took off the lid, and had a look inside and found the following (click to enlarge):


You will note the large brown circuit board that cover most of the inside of this amplifier. I have no idea how to repair this, so will be replacing this with a small circuit board purchased from eBay. The boards look like this:


There are lots to choose from I will deal with which one later in this post. I am using the TPA3116. As I have some past experience with this board.

Upcyling / Recycling an Old Stereo Amplifier - Chapter 1 - Which Bits to Keep

So after removing all of the bits you do not need you will end up with this (click to enlarge):



I have removed the large heat sink because I am using a Class D Amplifier so  I will not need the large heat sink, if you are choosing a Class A or Class AB amplifier then it would be a bonus to reuse your heat sink. 

A good quality power supply will cost quite a lot, so the one you have is worth keeping. The power supply might be AC rather then DC current, check this with a multi meter. If it is Look out for the bridge rectifiers and keep those too so you can make DC current for new amplifier board! 

This power supply gives out multiple voltages, which is very handy. I suspect most amplifiers will have this arrangements as they will need to power low voltage lighting and higher voltage amplifier chips. The voltages from this supply are "non" standard. They are not 12, 24, 36 etc. they are 17, 27 43 etc. thye go up to 93V so risk of a shock there if I am not careful!

Also the RCA inputs and Output Terminals and any other input / out put parts might be worth keeping. There were also some large capacitors, which may come in handy for decoupling.  


Upcyling / Recycling an Old Stereo Amplifier - Chapter 1 - Watch a Video Summary




I have tried to summaries findings in Chapter 2. . . although for a full description of what went wrong perhaps head over to DIY Audio






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