Chinese knock-off headphone amps

Has anyone had experience with Chinese made copies/knock offs of headphone amplifiers, specifically the A2's and Krell KSA5's seen on eBay? They seem well made with quality parts. Would I be throwing my money away by purchasing one?
These rampant illegal Chinese POS units are not “knock-offs”. They are illegal, crummy / crap-build, lame counterfeit fakes that are NOT made with the same quality parts as OEMs.

The colloquial term “knock-off” is often used erroneously interchangeably with “counterfeit”, but their legal meanings and practical experiences are very different,

“Knock-off” products are those that copy the build and imitate the physical appearance of OEM licenced brand products, but which do not copy the brand name or logo of the trademark.

These Chinese counterfeit fakes are illegal fakes with grossly inferior/ crap quality build, that can only lamely tries to duplicate its legit subject OEM unit in EXTERNAL appearance. Inside, you get exactly what you paid for - only pure shite performance….  cheap garbage in = only more garbage out …full stop.

I'll sell you an early Schitt Lyr that's been used for a total of about 2 hours and is in perfect condition if you want a head amp. I loved it but it drove my wife crazy. I'll thrown in the AKG 702's ( I think that's the model) and a headphone holder that mounts on a shelf. I keep forgetting I own it. It sounds very nice but not worth my marriage.

Graham slee makes some very good headphone amps, you should check them out. I have a Graham slee novo and I’m very happy with it. It has a daisy chained output so that you do not lose an rca output on your preamp. This is great if you run a tape deck or mini disc recorder etc...I have run many a headphone through the novo and it performs great.
Simple rule to adhere to. If it is on ebay or amazon figure 90% is counterfeit knockoff china garbage. Even toilet paper from amazon is fake. Age old rule of thumb you get what you pay for and if it seems to good to be true it is. This is not only my opinion I know many people who work in customs that have confirmed this. I no longer by anything from amazon I go direct don’t care if it cost me shipping.