I compared rings on both cups and it doesn't seem like it's broken. Maybe the ring is not holding the grill tight enough. I'm definitely going to ask Hifiman and see what they have to say about it.   I just tried mineral oil and it definetly got better. Too bad it's so difficult to...

I would really apreciate if someone could comment on this. I've come to the conclusion this doesn't affect the sound but it still bothers me.   I also have a problem with the screw that allows the cup to turn in the horizontal plane, it's too tight. There's quite a lot of strain on the head...

The right grill seems to be a bit loose for me. When I tap gently on the blue part of the cup I hear a ringing sound. The left side is just dull with no ringing at all when I tap it.   Has anyone experienced this, or even have a solution? I tried putting small bits of plastic under the ring...

I found a pair of RCA 5963 for a decent price. After reading a bit it seems like they should be a suitable replacment for the 12AU7. Searched the thread and I couldn't find any comments on them. Will they work?

Thanks for the answers. I'm going to buy some quality solder instead. Any recommendations on what to get and where?

Quote: But the strange thing is that my 60/40 solder works fine under the exact same conditions so I dont think temperature and size is a problem. Just to be sure I cranked up the temperature to 450°C and heated excessivly long and the result is still the same.  

Quote: Bojie, bought it on ebay, quite cheap.   Using a chisel tip at 360°C (680°F).

I bought some eutectic solder ( 63/37) to use for my first smd project. I tried it out on some cables and through hole components and I'm not pleased with the results. The joints are not shiny at all, especially compared to my 60/40 solder. I suppose this is not good to use? Would it be...