I have a unique perspective since I repair Chinese amps along with the more garden variety vintage and new stuff. Some of the Chinese amps are pretty horrible and should be avoided at all costs.
Here's a fake NCC capacitor. The logo text is just gibberish.
This is not how you'd want to see a wire attached. This particular amp made about half the power it claimed to.
Here are some blown caps on a Chinese 845 amp that hadn't been used very much according to its owner.
This amp also had some fake caps. These are also fake NCC caps, but with different text inside the logo. What you have to understand about these parts is that there's no name and no liability behind what's on there. If you look for the name brand printed on these caps, it's defunct already!
And some wire nuts for good measure!
I did one round of repairs on that amp and replaced every single electrolytic cap in the amp. I also discovered that the balancing resistors they used across each cap in the high voltage supply would overheat and fail, and when they failed they would become a dead short and take out the rest of that power supply node (resistors usually fail to infinite resistance, but I think these were encased in metal). I also warned the customer that I thought the filament rectifier diodes would overheat if he ran the amp for more than 5-6 hours, and after he left it on overnight I got to do another round of repairs to add beefier rectifier diodes.
(Boards I had made to fix the rectifier issue) After all this work, this amp has been running reliably for a few years now, but the repair costs were more than he paid for the amp.
I had a pair of Shuguang 845 amps come across my bench and one power transformer had a short from the high voltage winding to the 120V mains winding. I contacted Shuguang and the domestic distributor at the time about purchasing a replacement power transformer and never even received a response!
I had to have a new pair of power transformers made for these amps and they had to be bigger to meet the specifications of the amp, so they wouldn't fit under the transformer shrouds. This was a very costly repair for the customer and his amps were out of commission for three months while I waited for the power transformers to arrive.
Having brought all this up, I have seen Cayin/Yaqin amps in here that measured pretty well, weren't insanely difficult to work on, and would likely give pretty long service life. I have no idea what parts availability is like for any of this stuff, and that alone would have me recommending a used Rogue, VAC, or something Dynaco based where there's a wealth of knowledge and reproduction parts available.
I have also been inside a few Line Magnetics amplifiers and saw absolutely nothing in terms of the parts they were using that looked anything other than 100% genuine and carefully chosen.
