Sure, DIY amps usually don't have UL or equivalent approval. However, if you sell an amp without such approval, it may not be legal.
If I would sell one of my amps, I'd disconnect the mains wires from the IEC inlet, remove the IEC inlet from the chassis and tell the buyer that this must be done by someone who knows what he/she is doing and can provide safety approval.
If I would sell one of my amps, I'd disconnect the mains wires from the IEC inlet, remove the IEC inlet from the chassis and tell the buyer that this must be done by someone who knows what he/she is doing and can provide safety approval.
Zooming in on the photos above it looks like the PE connection to the chassis is done with with a fork lug, not a ring lug. I'd suggest to change that to prevent the lug from falling off. Also, a spring washer may be a good idea to prevent the screw from coming loose.
That sounds like speculation, though. I haven't been able to find any hard legal requirements (for the US) that NRTL certification must apply to electrical products for the home. It should also be noted that strictly speaking, bodies like UL don't grant approval.
Not having certification could result in insurance liabilities, and retailers are highly likely to reject uncertificated products, so it seems more a matter of commercial good sense to ensure that a mass-produced item is properly covered. Additionally, if export to or import into the US is involved, there's another reason for wanting potential obstacles removed.
These issues are more or less normal/accepted in these devices. Apparently stuff can also be imported and no more official testing but “self regulation” by the manufacturer. DIY is another matter.
Even very expensive tube devices sometimes have 3 prong IEC inlets with PE not connected and Audio GND connected to chassis. Then there are also owners that don’t have the time/money/motivation to have PE wall sockets in their home to connect their 5000 Euro device with PE equipped IEC inlet to. Safety is not on the priority list.
It is no surprise having hum and grounding correctly are both returning subjects. When solving issues one will often hear that it was designed by (insert famous name here) and it was made by (insert important name here) and costs mucho $£¥ as an explanation for the perceived quality (of a device that has issues right at that moment).
Even very expensive tube devices sometimes have 3 prong IEC inlets with PE not connected and Audio GND connected to chassis. Then there are also owners that don’t have the time/money/motivation to have PE wall sockets in their home to connect their 5000 Euro device with PE equipped IEC inlet to. Safety is not on the priority list.
It is no surprise having hum and grounding correctly are both returning subjects. When solving issues one will often hear that it was designed by (insert famous name here) and it was made by (insert important name here) and costs mucho $£¥ as an explanation for the perceived quality (of a device that has issues right at that moment).
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I am not familiar with the situation in the US or other non-European countries, but I would be surprised if it were fundamentally different. European countries require certification for all relevant products that are put into circulation. Good luck with selling a DIY amp.
P.S.: the regulations are not limited to "mass produced" devices.
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I'm not trying to sell one, or urging anyone else to. Nor did I attempt to speak for Europe. That's clear enough in my comment, which specifically mentioned the United States. I did however try to find what US requirements are, and was unable to find any definite statement that Federal or state laws require UL type certification.
And it may be a mistake to just assume that because something's done one way in Europe, it's done an equivalent way in the US or Japan. Plugs, outlets, and wiring are handled quite differently here than where I'm from.
As another example in addition to the Japanese residential setup I mentioned earlier, the overhead power lines found in Japanese neighbourhoods are generally insulated. I understand that in the United States, they are generally not. That's two rather different ways of doing things. Who's right? Who's safe?
Electrical matters outside the home are not changeable by its users. It is the home environment where safety for consumers is of interest.
Regardless of national pride and perceived superiority safety by means of internationally agreed upon regulations/standards like PE is of anyones interest.
A very good example is the 3 prong IEC inlet. Safe, sturdy and accepted literally everywhere.
Regardless of national pride and perceived superiority safety by means of internationally agreed upon regulations/standards like PE is of anyones interest.
A very good example is the 3 prong IEC inlet. Safe, sturdy and accepted literally everywhere.
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Ouch. I wasn't under the impression that anyone was pushing that angle. Definitely not me. The questions in my last comment were rhetorical, so you may have misinterpreted my intent.
May be of interest
Grounding Basics: What are the Differences Between PE and FG?
Ground rules: earth, chassis, and signal ground
Edit to add:
I'm not an expert, but in the absence of a schematic and assuming that the amplifier is built without electrical errors, it coud be a good choice. IMO
No one can say whether it interferes with SQ, though.
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