Just received my yaqin tube buffer after waiting almost 8 weeks for it and having to pay an extra unexpected £14 Vat import and handling fee from china, I hooked it up to find that it doesn’t work properly. I am really annoyed now especially after waiting all this time and paying the extra costs.

When connected to my CD into the input and the output then goes to my amp it just gives a lot of feedback through the speakers ( a loud humming and the music can just about be heard underneath it, then if is is switched off, just the same. I emailed the seller on ebay and he said just check the connections and email me back if not I will send you more tubes, however I have tried it with the tubes removed also and it sounds exactly the same, so I think it is not the tubes at fault. I have even tried just for curiosity connecting my CD player to the output and the signal to the amp from the input, this does let the music through with no humming but it does degrade the sound quite a bit and it doesn’t make any difference really if the unit is switched on or off. Has anyone had similar experiences with the unit?

I am in talks now with the seller trying to get the yaqin 6J1 Tube Buffer issue sorted out, but if you haven’t bought one or are considering buying one of these from china it may be useful for you to know about this. I initially paid £60 for my unit.

That's too bad. I think that probably some solder joint is broken or a bad resistor in the ground line or it is not grounding at all...
BTW, have you tried other pairs of interconnects?

Chinese tubes are a huge gamble, expecially when buying through the mail. Hope you get your issue sorted.