The 840A is a Douglas Self Design, designed in the UK by him and his UK team based near London Bridge, then built in China.
It does what an amplifier needs to do.
But we have clearly established that we have different needs. You can't or wont hear differences as your intellect tells you they are illusions.
And so what Douglas Self designed it, you could just have easily said Fred Bloggs had designed it, it means nothing apart from that like Ken Ishiwata he has bullshited himself more than his products.
It is built in China, do you know what that means, well I do because I know the Chinese mind and the Chinese ethic, why, because I am adopted Chinese. Chinese tradition means only members of your family are important and any one above you is to be publically kow-tow-ed to and any body below you has to kow-tow to you in public - it is all about "face". But behind *everyones* backs you rip off and make money any way you can, and the conflict this creates is astonishing which is why Chinese history is so violent. The pressures just build up until they explode. Confucian (Con-Fu-Shi) philosophy was created to try and control it, and the most successfull at it has been the Communist Party of the Peoples Republic of China. Everyone in the west sees Mao as a Hitler, but he understood China, and the way China functions today is the best compromise for continuing to function without going off on one of its historic bouts of mad self destruction. I am not saying Mao was a great man, but in many thing he deserves more credit than he gets.
I suppose I should explain why I am adopted. In China if you want to learn something traditional it will always be a secret that is only taught to family members, and not daughters (though this has now changed and the female voice will be the salvation of China). Daughters do not belong to your family, they belong to the future family of their husband. My Tai-Chi Master Tian Yin Jia who lived in Shanghai, appointed me as a Tu-di, roughly translated as son/disciple. My responsibility was to show him the respect of a father and his part of the deal is to give me the real goods.
So how does this apply to Chinese manufactured goods. Well the number one priority is to cut corners and costs in order to compete better for price and make profit. The only thing that is important is perceived value, not actual excellence, and the west has been feeded on it greedily like a drug. But what you get is cheap product that is on the edge of function as it is cut to the bone and may cost half the price of a European product but will have less than half the life.
Now just a little promotion and product shilling as an example. I have amplifiers 30 years old still functioning perfectly without even the bullshit of needing cap changes, you see how many of these Chinese amplifiers are still functioning in 30 years, we are now addicted to the throw away society.
Now the Japanese are and were different, for them "face" means excellence and respect for company (which becomes part of self) so for their home market products they are truly excellent, but for foreign devils they couldn't care less, we are here just to sell the crap to.
Ask any Chinese living in China if he wants to buy Chinese product, he has to unless he is rich. If he is rich he wants western product as he know what the Chinese production is like because he is part of it. This was never the case with the Japanese they were proud of excellence and their products for their own people showed this.