Repurposing CRT TV speakers

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Fluffyboii

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Hi, I taken apart an very large Sony CRT TV today to harvest the materials. The speakers look like they are made by Sony and they seem to have somewhat good quality. Original circuit uses 2X TDA7482. But it is integrated to whole TV motherboard. So can someone recommend me a speaker amplifier circuit from this parts. It got base and tweaters so I am not sure how to drive it. I want to use the old parts as much as possible. Thin speakers are 16 Ohms. IDK the subwoofer specs.
 
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I am also planning to make a 3D printed case for them to get a good looking end product. I think these speakers should be much better than my cheap pc speakers. Also I am going to harvest the Flyback transformer. Is there anything else I can harvest that will prove usefull from this.
 

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TV speakers aren't usually much good, but could be driven by any small amplifier, the tweeter is simply connected to the main drive unit via a capacitor (simple high pass filter). I would expect any reasonably decent PC speaker to be better quality.

However, from the picture it has a sub-woofer, which means you need three amplifiers, not two, plus an active low-pass filter to feed the sub amplifier.
 
The tweeters are directly parallel connected to the thin long speakers. Honestly I am using a 1+1 cheap USB speakers. These would be much better. Also I am extremely bored and I want to do something with these. I can take more photos of the motherboard if you desire.
 
I suggest you look on ebay or Aliexpress for a TPA3116 based amp module.
Examples -

Stereo:

Digital Audio Power Amplifier Module TPA3116D2 2 * 50W Dual Channel Stereo | eBay

Adopt high quality TPA3116D2 power amplifier chip. Amplifier chip: TPA3116D2. Output power: 50W+50W dual channel. 1 x Digital Audio Power Amplifier Module. Output power 15W+15W, dual channels stereo.
www.ebay.co.uk

2.1 Channel

HOT 5.0 Power Amplifier Module Board 2.1 Channel Digital Audio 100W+2*50W 759910802463 | eBay

Find many great new & used options and get the best deals for HOT 5.0 Power Amplifier Module Board 2.1 Channel Digital Audio 100W+2*50W at the best online prices at eBay! Free delivery for many products.
www.ebay.co.uk

They are not bad for the price, perfectly good for PC speakers - the same device type as I use in my home built PC speakers.. The ratings are typically rather exaggerated (especially if only on 12V), but still perfectly usable.

Aim for ones with visible inductors and decent size capacitors like those above; some have rather under-rated components.
 
This looks like a good and easy way. But I would like to build the circuit myself since the TV already has most of the required components on the board.
 
Actually I checked and it is cheaper to buy a second hand 2+1 system than one of those boards :/
 
Use the application notes in the data sheet for the TDA7482 and mark the printed circuit board where to saw-off and extract the whole original circuit with all the pertinent components. Then add a supply, inputs and connect the speakers.
 
The sample circuit board doesn't have any values listed, I can't decide them All of the simple and cheap amplifier circuits lack subwoofer output. Is there a way to add it by using another amplifier with low pass filter in its input. Also how people build stereo amps with one mono amplifier IC. I really don't want to buy a premade amp board since it destroys the purpose of using old materials and costs more than a 2+1 speaker set.
 
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A stereo amp, or two independent amps, are often used to drive a single speaker. By inverting the of the two inputs, the outputs will be out of phase. This effectively doubles the voltage that is sent to the speaker.
 

Even crappier then, presumably the 'tweeters' are just crude piezo discs?.

If you post the model number it would help, a 'similar' Sony model is the KV28LS35, service manual here:

Elektrotanya for electronics experts

Electronics forum for electronics experts to repair defective appliance.
elektrotanya.com

That model uses a TDA7497, which has three amplifiers in it, left, right and sub. The TDA7482 you have is just a single channel non-bridged amplifier - so it must have two for left and right, plus a third (or something better) for the sub.

You should be able to download the service manual for your set from the same site.

All that makes the sound quality 'reasonable' in the set is the sub-woofer, the other speakers are crap, as you can tell by their size and shape - the following years 'improved' model (the KV28LS36) was exactly the same as the 35, except they left the sub-woofer out (known as 'cost improved' in the trade), and as you would expect the sound quality was pretty useless.
 
It also has LM1876 with a huge heatsink on board. I was wrong to say tweeters are parallel connected. There seems to be something in heatshring between them and the long speakers. Probably a high pass filter as you said. I will ask my friend about the model number of the tv.
 
Fluffyboii said:
It also has LM1876 with a huge heatsink on board.
Click to expand...

The LM1876 is a stereo amplifier, so it's probably bridged to increase the power for the sub-woofer, bass needs much more power than high frequencies.

Fluffyboii said:
I was wrong to say tweeters are parallel connected. There seems to be something in heatshring between them and the long speakers. Probably a high pass filter as you said. I will ask my friend about the model number of the tv.
Click to expand...

Most likely just a simple capacitor, the crudest high-pass filter you can get.
 
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