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Forum Index : Microcontroller and PC projects : Cute little 2.1 amp for your PC...
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9059 |
I got one of these from AliExpress during the Christmas holidays, and I am very impressed with it! Link to amplifier... This one has both a standard 3.5mm analog audio input socket, and also Bluetooth 5 wireless audio. Considering it's absurdly cheap US$12 price, it works VERY well indeed. With a 13.8v DC supply, it blows the room apart, with very nice control of both the sub volume AND the crossover frequency - a feature most 2.1 amps DON'T have, especially at this price point. Comes as a sort-of knock-down kit, requiring some simple assembly, but you get all the bits including the knobs and even a DC-to-terminal adaptor thing for power supply and even a cheap screwdriver! All this comes packed inside a nice cardboard box. Audio is via 3.5mm plug or wireless BT5 connection, but NOT BOTH - one or the other. Excellent insulated terminals for the speaker connections, and very cute panels with labelling etc on it. Very impressive for twelve bucks!  Windoze sees it as a "Stereo headphones", with an ID of WUZHI, which matches the name of the amp itself, so finding it and connecting to it was dead easy - not always the case with cheap BT stuff out of China. I don't know how much faith I would put in the 50W+50W+100W rating, but it sure has plenty of grunt for a set of modest PC speakers or perhaps for your gaming rig.  Smoke makes things work. When the smoke gets out, it stops! |
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Mixtel90 Guru  Joined: 05/10/2019 Location: United KingdomPosts: 5712 |
I think that this will ust about fit in that little Hammond 1593 case that I've been using. Might need a dremel to take the pcb supports off the top half. :) It's a rather nice looking little amp. Might have a radiated interference problem as it stands though. It'll be bridged class D but the speaker outputs appear to be unfiltered. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 1777 |
" It'll be bridged class D but the speaker outputs appear to be unfiltered." If so connect the speakers with microphone cable. Shielded twisted pair. |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5712 |
... and instantly the hi-fi aficionados will throw up their hands in horror! :) I see they also do a "hi-fi" version of the amp that includes output filters. Well, they refer to it in the ad, but there don't seem to be any. Edited 2023-01-09 22:07 by Mixtel90 Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9059 |
Brilliant idea.   I never bothered to measure it's EFI, but perhaps I should try to dig out my EFI probe thing. Bah. Who cares.  Smoke makes things work. When the smoke gets out, it stops! |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5712 |
Who cares? Every radio amateur within a 50 mile radius. :) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 5898 |
You will if it interferes with one of your wireless links. Jim VK7JH MMedit  MMBasic Help |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9059 |
OK, OK. I'll see if I can find my EMI probe thing and test it. Smoke makes things work. When the smoke gets out, it stops! |
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hitsware2 Guru Joined: 03/08/2019 Location: United StatesPosts: 705 |
Stick with class AB so as to have no concerns my site |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5712 |
Even better, stick to class A. You'll have a nice room heater thrown in. :) (My little headphone amp uses a paralleled ECC82 followed by a source follower class A MOSFET for the output stage on each channel. It's lovely in winter.) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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Bill.b Senior Member  Joined: 25/06/2011 Location: AustraliaPosts: 225 |
This model appears to have output filtering. Amp  Bill Edited 2023-01-12 20:19 by Bill.b In the interests of the environment, this post has been constructed entirely from recycled electrons. |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9059 |
Nice find, Bill. Thanks. EDIT: Further searching revealed this amp with filters for NZ$25, so I think I will just get one of those as that one has the filters on-board also. Same company, same features, same knob layout etc, just with the additional output filtering. Edited 2023-01-14 14:15 by Grogster Smoke makes things work. When the smoke gets out, it stops! |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5712 |
That's a beast! Cheap too. :) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9059 |
The $12 one I have here now, kicks ass, BUT it HAS revealed some issues with the BT connection. Once connected to some long-ish speaker leads, although it sounds fine, the BT keeps getting SERIOUSLY corrupted, and the audio sounds like it it underwater most of the time.  Connecting via a hardline 3.5mm lead totally fixes this problem, so perhaps we do indeed have an EMI radiation problem - the speaker leads acting as transmitting antennas to some extent, which then swamp the BT connection. I have not yet found my EMI test probes, but that is what I am thinking. But with the new version with built-in filtering, I am hoping that perhaps the BT connection will work better. If not, I can still use the hardline AUX input. Smoke makes things work. When the smoke gets out, it stops! |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5712 |
I bet it's radiating like mad. A flourescent tube or a neon might light near the speaker leads. :) Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9059 |
LOL!!!!  Perhaps I will see if I can find a neon. Might be easier then finding my EMI probes at this point. Smoke makes things work. When the smoke gets out, it stops! |
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| phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 1777 |
You could always knock up a filter on some strip-board. If it won't fit inside just attach it to the terminals. |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5712 |
Too easy, Phil. :) Ferrite beads & little caps are all that's needed to get rid of AM band RFI according to the data sheet. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| hitsware2 Guru Joined: 03/08/2019 Location: United StatesPosts: 705 |
The switching going on in a P.C. itself degrades audio enough , without adding switching in the amplifier . my site |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 5712 |
Not a problem in many cases. It was already degraded when you got it. First at the mixing desk then it went progressively downhill... I have a little Class D (although the chip manufacturer calls it something else) amp here that I've been using for several years. Built from one of the Chinese modules. With a pretty meaty power supply and some local caps on it it sounds pretty good into some B&W DM4 speakers. Well, it does to me anyway and that's what matters. :) It's being hopelessly under-run so there's masses of headroom available, which might help. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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