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Audio Magic Blue Dot - foo?

Dowser

Dowser

Learning to bodge again..
Hi All

Picked up one of these very cheaply recently - anyone have any experience of them? Fair bit of info on the net, looks foo-like at first glance :)

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52766651974_2557adba8a_k.jpg


Plugs into mains socket and a spare RCA - only earth of RCA connected to Blue Dot. Something was bouncing around inside this one, so wanted to open it before plugging it in. Haha - as well as the 4 case (cheap plastic box) screws, they also glued the damned cover on - always a good sign :D

Hack-sawed the back two corners and prized open with a screw driver. Thing bouncing around was a bit of crystal that had come away from the copper ground plane that the RCA earth was connected to - it's covered with glued on crystal.

Active side is more of a concern - supposed to suppress RFI/EMF - this thing has not gone through any sort of safety certification process I think?! I think you can still buy one of these for $850! Hopefully put together a little better than this :)

52766812910_79983f9bb7_k.jpg

52766651954_03afa9869d_k.jpg

Any electronic engineers want to guess what this is doing? Clearly doesn't give a shit whether powered by 120 or 240 volts, LOL :)
52766888078_b072f2dc66_k.jpg


So, am I going to be reckless enough to plug this into my system? You bet I am - stay tuned :D

Richard
 
I wasn’t sure but the last time I saw something like this the cat had puked up. Crystals you say
 
Precision made device...

So, that's a 25k resistor across the mains, all held in with blobs of hot glue. Looks bloody dangerous.

Go on, what's the chip marking. Obviously there a couple of diodes as a rectifier, a smoothing cap and a zener (maybe), dc to the chip.
 
Dowser said:
Hi All

Picked up one of these very cheaply recently - anyone have any experience of them? Fair bit of info on the net, looks foo-like at first glance :)

52765861602_59a0f3ea10_k.jpg

52766651974_2557adba8a_k.jpg


Plugs into mains socket and a spare RCA - only earth of RCA connected to Blue Dot. Something was bouncing around inside this one, so wanted to open it before plugging it in. Haha - as well as the 4 case (cheap plastic box) screws, they also glued the damned cover on - always a good sign :D

Hack-sawed the back two corners and prized open with a screw driver. Thing bouncing around was a bit of crystal that had come away from the copper ground plane that the RCA earth was connected to - it's covered with glued on crystal.

Active side is more of a concern - supposed to suppress RFI/EMF - this thing has not gone through any sort of safety certification process I think?! I think you can still buy one of these for $850! Hopefully put together a little better than this :)

52766812910_79983f9bb7_k.jpg

52766651954_03afa9869d_k.jpg

Any electronic engineers want to guess what this is doing? Clearly doesn't give a shit whether powered by 120 or 240 volts, LOL :)
52766888078_b072f2dc66_k.jpg


So, am I going to be reckless enough to plug this into my system? You bet I am - stay tuned :D

Richard
Click to expand...

A lesson in how not to build something properly...:eek:
 
Dowser said:
... So, am I going to be reckless enough to plug this into my system? You bet I am - stay tuned :D
Click to expand...
All I can say is eek! In my book it's unforgivably crude at any price.

I recognize how that power supply to the IC and LED works (whatever the IC actually does). I learned how to bodge that sort of transformer-less low-power mains power supply when I was a neophyte electronics hobbyist at age 14. I look back at that time and I am horrified at the risks I took with the mains supply before I knew better.

Is that really mains earth connected to the copper sheet and then directly to one side of the RCA plug? If so I would not connect it to any audio system I valued.
 
A brave departure from the lavishly over-engineered uselessness one usually sees in this arena.

PS As others have said I suspect much of it is a PSU for the bright blue LED.
 
John Phillips said:
Is that really mains earth connected to the copper sheet and then directly to one side of the RCA plug? If so I would not connect it to any audio system I valued.
Click to expand...

To my eyes it looks like the RCA plug is connected to the screen of the white mains cable and that’s about it. Without knowing whether this screen is connected at the mains plug it is hard to know if it is even an earth. The rest of it looks to be out of circuit aside from powering an LED.
 
I missed the led on the right, hidden under the delicate blob of hot glue ...so the chip doesn't make it flash? I'm disappointed, I'd want my money back.
 
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