Electrical Safety of AliExpress equipment

Can anyone speak to the electrical safety of the JLH1969 amplifier or any popular options that are available from AliExpress? I am always concerned with low-cost electronics like this after I read about a few cheap 3D printers catching fire. Granted, an amplifier isn't shooting out melted plastic. I am sure the many of the reports are isolated incidents, but the idea of a house fire has kept me away from them.

 

I'd like to see a reviewer handle that in a review.

Pros: Good price, realistic timbre, solid instrument separation
Cons: Treble extension could be better, small volume knob, catches fire

 

The grounding scheme isn't ideal by today's standards, but a lot of my vintage equipment is grounded the same way and I've never had any problems.

These amps run really hot though, mine runs hot enough to put brown spots on a white piece of paper if set a top for several hours.

 

The ground lug on the power socket on the jlh69 I got from aliexpress was floating when I got it. That’s somewhere between annoying and unacceptable depending on your druthers. It was an easy diy job to solder it to chassis ground but that didn’t fix the super annoying buzz I get when using this amp in a biamped system. It’d probable be fine running full range. I think my minidsp unit is causing the buzz, not the jlh69.

 

I actually just read your post on this in another thread and will attach it similarly if I purchase one. I'm not disturbed by the Class A heat production, but things like this are what give me pause. I'm not sure I'd have looked inside if I bought one without researching first, so I guess that needs to become a habit rather than just satisfying curiosity.​

 

Just checked the LPS I got from AliExpress for my MCTH and the ground prong isn't tied to the chassis. Should I connect it to the chassis? Haven't opened it up yet to see if it's connected to anything.

 

"Float like a butterfly, sting like a bee ..."


There's some solder on it, so maybe they were gonna but forgot, or it was repurposed from another product.

So I assume "chassis ground" is any one of the bolts going through the chassis.

Here in Taiwan, the "third prong" is highly optional and more often than not non-existent on domestic electronics. Most older homes only have 2-prong sockets and you end up having to break off the ground prong or using an adapter. Houses aren't burning down left/right/center, at least not from electrical fires caused by poor grounding. They're usually caused by space heaters in the winter and natural gas leaks.

 

In many older homes in the US, especially in areas of significant historical value, two prong sockets are the standard. While I'm (admittedly) probably on the border of irrational fear of house fires, I think it's probably better to proactively repair equipment that doesn't meet a recognized modern standard. You should definitely read the post by @philipmorgan at http://www.superbestaudiofriends.or...ess-ebay-jl-hood-1969-class-a-amp.4308/page-4 since I have absolutely no idea what I am talking about.

Then again, if your home doesn't have that third prong, it might not make any difference.

 

Before I read your post, googled a bit, made some continuity measurements, found a wire with an eye connector in my toolbox, and did exactly the same thing as @philipmorgan. It didn't blow up when I connected it back up to the MCTH, so I think all's good.

 

When the wiring inside is properly done up to power transformer there should be no fire hazard.
Then again not sure how safe the Chinese transformers are.
Plus it can still burn down with all the grounds and wires properly placed.
The ground is double safety, sure, but it sometimes also causes problems in performance. Hum, ground loops.

 

The old Singlepower Squarewave could be summed up almost exactly like that.

 

When I showed an electrician how I intended doing this on an industrial LPS adapted for the MCTH, he shrugged and said something to the effect of "if it makes you feel better". It's probably good practice if the pin is available, but yeah, like you say...