Hi,
Firstly I want to be clear that I am a complete novice with circuitry and electronics. I do have a healthy respect for electricity, and safety is always on my mind.
I had a mad idea to free up my Bose bluetooth speaker I've been using with my home pc so I can take the Bose back downstairs where it should live. I have some old Dell pc speakers but they're no longer working so I mused about how to replace them. I came across some old Hi-Fi speakers that would work well in my office, but being passive they'll need an amp.
The mad idea: I had an old Panasonic LCD TV ready for scrapping, and I thought "Why not take the amp and power supply out and make it into a speaker amp?"
That started me off, so I've now cannibalised the TV, and taken the boards out. I have the TV's service manual downloaded which tells me what the parts are.
So the issues I need to consider:
I'll need to create a line input, but the more I think about this the more I realise my knowledge limitations.
The TV volume would obviously be controlled by remote. I have also taken out the IR receiver, so could this circuit be used with a volume control?
Housing the amp. Is a wooden box suitable?
I'm not after anything high quality - that could be worked on once I have more experience, just something to listen to music whilst on the pc. I don't want to spend loads of money buying kits, I just want to learn how to do this and gain some satisfaction knowing I built it myself, with help obviously!
Apologies for the long initial post, and any pointers or advice to "Get out before you do major harm to yourself and your family" will be gratefully received.
Firstly I want to be clear that I am a complete novice with circuitry and electronics. I do have a healthy respect for electricity, and safety is always on my mind.
I had a mad idea to free up my Bose bluetooth speaker I've been using with my home pc so I can take the Bose back downstairs where it should live. I have some old Dell pc speakers but they're no longer working so I mused about how to replace them. I came across some old Hi-Fi speakers that would work well in my office, but being passive they'll need an amp.
The mad idea: I had an old Panasonic LCD TV ready for scrapping, and I thought "Why not take the amp and power supply out and make it into a speaker amp?"
That started me off, so I've now cannibalised the TV, and taken the boards out. I have the TV's service manual downloaded which tells me what the parts are.
So the issues I need to consider:
I'll need to create a line input, but the more I think about this the more I realise my knowledge limitations.
The TV volume would obviously be controlled by remote. I have also taken out the IR receiver, so could this circuit be used with a volume control?
Housing the amp. Is a wooden box suitable?
I'm not after anything high quality - that could be worked on once I have more experience, just something to listen to music whilst on the pc. I don't want to spend loads of money buying kits, I just want to learn how to do this and gain some satisfaction knowing I built it myself, with help obviously!
Apologies for the long initial post, and any pointers or advice to "Get out before you do major harm to yourself and your family" will be gratefully received.
Buy another PC speaker, or a 3116 kit.
Making the TV into a PC speaker is too much effort.
You can use the speakers off the TV, but the power consumption in the circuit will be too much, and unstable.
Go to a flea market, buy old speakers and amps, give them a clean up, check them out.
If you can afford it, buy a home theater, rig it wherever and use it.
$40 and up for new.
Making the TV into a PC speaker is too much effort.
You can use the speakers off the TV, but the power consumption in the circuit will be too much, and unstable.
Go to a flea market, buy old speakers and amps, give them a clean up, check them out.
If you can afford it, buy a home theater, rig it wherever and use it.
$40 and up for new.
Your idea is not very promising in any aspect, plus very dangerous because of the switching power supply.
A finished 3116 mini amp is about 20 pounds, they use a laptop power supply you sure have flying around. In most of these, there is a small chip, NE5532 on a socket. These are usually fake and deteriorate the sound. Try to get a real one, the sound should be perfect then.
Look for one like in the link. Prices for the same part are 20-80 or even more.
https://m.media-amazon.com/images/I/51mbL7I3XlL._AC_SX425_.jpg
https://m.media-amazon.com/images/I/41n5JJf89iL._AC_SX425_.jpg
DollaTek Mini Dual TPA3116 Digital Power Amplifier HiFi Stereo Audio Amp 2.0 Channel 100Wx2 DIY with NE5532 Pre-level OP Amp: Amazon.co.uk: Electronics & Photo
PS they are sold under different names, the PCB inside is important
A finished 3116 mini amp is about 20 pounds, they use a laptop power supply you sure have flying around. In most of these, there is a small chip, NE5532 on a socket. These are usually fake and deteriorate the sound. Try to get a real one, the sound should be perfect then.
Look for one like in the link. Prices for the same part are 20-80 or even more.
https://m.media-amazon.com/images/I/51mbL7I3XlL._AC_SX425_.jpg
https://m.media-amazon.com/images/I/41n5JJf89iL._AC_SX425_.jpg
DollaTek Mini Dual TPA3116 Digital Power Amplifier HiFi Stereo Audio Amp 2.0 Channel 100Wx2 DIY with NE5532 Pre-level OP Amp: Amazon.co.uk: Electronics & Photo
PS they are sold under different names, the PCB inside is important
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CRT TVs are a better bet. The speakers are larger, and I suspect could sound reasonably good if thrown into a woodlike box stuffed with damping. Amps are usually conventional linear chip-amps and through-hole components on single-sided boards.
I still occasionally see CRT TVs left at the side of the road. Rear-projection TVs should have even better speakers.
On the other hand... there are zillions of iPod docks that have been unfairly discarded, since they nearly all have 3.5 mm input jacks that'll work with any analog line (or headphone) level source. I found an "iStereo" with superficially nice-looking drivers (dome tweeters!) in a wood-derived box next to a dumpster.
On the other hand... for under $10 delivered there are various nice stereo class-D amps as complete boards ready to use. The T-amps may be using fake Tripath chips by now (TA2020, TA2024), or there's some using Yamaha (YDA138, YDA148), plus a confusing number of other chip families.
I still occasionally see CRT TVs left at the side of the road. Rear-projection TVs should have even better speakers.
On the other hand... there are zillions of iPod docks that have been unfairly discarded, since they nearly all have 3.5 mm input jacks that'll work with any analog line (or headphone) level source. I found an "iStereo" with superficially nice-looking drivers (dome tweeters!) in a wood-derived box next to a dumpster.
On the other hand... for under $10 delivered there are various nice stereo class-D amps as complete boards ready to use. The T-amps may be using fake Tripath chips by now (TA2020, TA2024), or there's some using Yamaha (YDA138, YDA148), plus a confusing number of other chip families.
I built a pair of mMar-Ken6 boxes from Frugal-Phile (run by Dave/Planet10 here). They're intended for the metal cone Mark Audio Alpair 6, but if you take the centre spacer out of the port, it'll work well with the paper cone Alpair 6P, which is what I have.
As for the amps, I would build something around an LM3886 or LM1875 as they're very easy to use. There's also a plethora of Class D amps out there. You don't need much power for near field listening. 10 W would be plenty. I ran my speakers with a 5 W tube amp for a while (because I had it) and that worked great.
You might be able to reuse the boards from the TV, but unless it's a super modular TV, it would likely be much more hassle than it's worth.
Tom
As for the amps, I would build something around an LM3886 or LM1875 as they're very easy to use. There's also a plethora of Class D amps out there. You don't need much power for near field listening. 10 W would be plenty. I ran my speakers with a 5 W tube amp for a while (because I had it) and that worked great.
You might be able to reuse the boards from the TV, but unless it's a super modular TV, it would likely be much more hassle than it's worth.
Tom
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Thanks all.
As I should have suspected my plan was a bit daft. I’ve now binned that idea.
I recently came across an old pair of active pc speakers in a dark corner of a cupboard. They work fine apart from noisy control knobs which should be an easy fix. Unfortunately the speaker enclosures which used to grey are now yellowed. One option is to clean them up, but I really want to boost the sound quality if I can, by transferring everything over to some old passive hi-fi speakers which were decent quality in their day, and will look much nicer on the shelf above the pc.
Please feel free to point out the flaws in the following plan:
Moving the power supply and all circuitry across to the speaker cabinets is straightforward enough. I guess I need to check that the hifi speakers impedance is ok to connect up to the contacts in the circuitry. I’m making the assumption that the amp and the speakers themselves are compatible.
Anything else I should consider?
As I should have suspected my plan was a bit daft. I’ve now binned that idea.
I recently came across an old pair of active pc speakers in a dark corner of a cupboard. They work fine apart from noisy control knobs which should be an easy fix. Unfortunately the speaker enclosures which used to grey are now yellowed. One option is to clean them up, but I really want to boost the sound quality if I can, by transferring everything over to some old passive hi-fi speakers which were decent quality in their day, and will look much nicer on the shelf above the pc.
Please feel free to point out the flaws in the following plan:
Moving the power supply and all circuitry across to the speaker cabinets is straightforward enough. I guess I need to check that the hifi speakers impedance is ok to connect up to the contacts in the circuitry. I’m making the assumption that the amp and the speakers themselves are compatible.
Anything else I should consider?
Attachments
Put a bigger transformer, those tend to be flimsy, and a new power cap.
Also, switch on primary side, or direct. Some have switch on secondary, LED goes off, you think it is off but the transformer is still getting mains power.
Spray the pots, should be enough. And solder reflow on all switches and pots.
Or you could keep this in a small box, save the trouble of modifying a speaker.
Enjoy the music, should sound better than from tiny speakers.
Also, switch on primary side, or direct. Some have switch on secondary, LED goes off, you think it is off but the transformer is still getting mains power.
Spray the pots, should be enough. And solder reflow on all switches and pots.
Or you could keep this in a small box, save the trouble of modifying a speaker.
Enjoy the music, should sound better than from tiny speakers.
Or buy an old amp, or TDA7297/TPA3116 kits, use those to drive your speakers, use the output from the PC.
Those work too...
Those work too...
Actually give them a listen, the cabinets are big enough for a nice sound.
Transformer is 12V x 1.3 A, about 14 Watts, decent enough.
If you don't like the sound, then do as above.
Transformer is 12V x 1.3 A, about 14 Watts, decent enough.
If you don't like the sound, then do as above.
1 Quid 50 in flea market, works well.
Needed a bath, was all.
I use a 3.5 to 2 RCA, from PC.
20 Watts/ch / 8R, Matsushita chip amps inside, all other components top quality .
Needed a bath, was all.
I use a 3.5 to 2 RCA, from PC.
20 Watts/ch / 8R, Matsushita chip amps inside, all other components top quality .
Attachments
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You could just paint them. The scratchy pot is easily cleaned with a contact cleaner such as Deoxit. Deoxit FaderLube is your friend as well.
Tom
Tom