Linlai E 6sn7 tubes

I'm not having issues with any other tubes. Just the Linlais.

Tomorrow I will measure the pin diameters and compare. Then take the preamp apart and check for solder joint cracks.

Then I may force the tubes in without the lid attached and support the PCB from the back side and see if the pins seat all the way.

Then I will await the extenders. Or have a bourbon first.😌

@bugredmachine with your level of determination and persistence, you'll get it figured out. The bourbon idea sounds pretty darn good about now 🍾

I think the 5852 tube messed up that circuit, which happened right before the Linlai's showed up. I had another 6X5 do the same tonight so I think when everything warms up the damaged component is flaking out. Perhaps the Linlai's irritate that component from the jump. Not sure if they draw more power than vintage 6SN7's.

the 30 minutes of beautiful music, with no hiss BTW, using Treasures and Full Music 6SN7's was wonderful. Right up to the rectifier going crazy like the 5852 did. I'm waiting for DOn to make some suggestions and I'll open it up tomorrow and poke around. Maybe I cracked a solder joint pushing the tubes in and out.

@bugredmachine I am not any EE, but do have mostly bespoke built Valve equipment, yours is a good call on a defect possibly to be discovered in the circuit. Whatever might prove to be the cause, as it is seemingly able to cause two Tubes to offer a similar level of interference on either channel, if a fault is found,  it will potentially be a similar condition found on both channels. 

Hopefully the E 6SN7 will present as described by others if a circuit fault is found and corrected.

On a different thought pattern, I have a Valve Phonostage, that has been Tube Rolled and has Vintage Mullard E88CC Tubes in use.

I learnt in the recent past, that a socket adaptor can be used to allow for the use of a 6SN7 Tube. I am now thinking a socket adaptor coupled to a offset adaptor as in use by others with oversized Tubes will be a small outlay to enable a extension of the use of the Tube Trialing beyond the Power Amp' and include the Valve Phon' in the trials. The owned selection of 6SN7's inclusive of the 'to be purchased' Linlai 'E', are perfect as Donors. The method to use adaptors will enable the use of KR VT 231 and the Linlai 'E' to be swapped for their positions in the Power Amp and Phon' to see if a configuration is improved over another, I am not able with owned Items able to have both devices coupled with the same Brand Tubes.

Is there more to extract from the already very much enjoyed Power Amp and   Phon', Hmmmm?

Received my replacement pair from China and FINALLY, they are almost completely hiss-free. Magnitudes better than the other 2 pairs I have tried.

While I was getting 8 inches of hiss on all my other tubes, these are about 20 inches, evenly so left and right, and not heard from my seating position. Yippee.

And pretty friggin' good too. Tremendous body to all instruments. Saxes jump right out at you. Have them paired with the Shunguangs right now but I prefer the Full Music and will try those tomorrow in the second seat.