I installed a quad match set of the new production Mullard tubes, and this little Cayin really lit her up! The Mullards are a very good sounding tube in this particular amp. the stock tubes were just a bit on the thin or bright side, the Mullards really added that warmth my speakers sound best with.
I settled for the tholin pt 10 or higher readily available within the eec without taxes and free inexpensive shipping. I gave waiting for drop to ship 220 volt cayin products. I asked for the 220 volt for years from drop without any productive reponse.
110 volt a g a i n for the 5th or sixth time. Nonetheless I still believe in miracles. Some day the 220/240 volt will be shipped. Some day, some day, some day. Never stop believing.
So just a 30 day return window and no actual warranty. Why would anyone purchase a $800 amp knowing after thirty days it could become a worthless brick?
EvshrugThis is a wonderful little amp, I have had mine for a couple of months. I also had the MT12 EL84 amp Drop is also selling, never had any issues. I have other Cayin gear, again never any issues. They are a high quality manufacturer of stereo gear.
Aka_maverickSadly, the only direct replacement for a 5BK7 tube is another 5BK7. Pretty much any other option would require modification of the amplifier, especially with regards to the heater voltage. The 5BK7 tube uses a 4.7v heater, while most potential alternatives use 6.3v or 12.6v heaters.
Best bet if one were to buy this is to immediately start scouring the tube sales storefronts for matched and balanced 5BK7/5BK7A, and buy enough for the expected lifespan of the amp. Good luck there. In theory, most of the 5BK7A tubes should give something around 5000 hours minimum (~2 years of usage 8 hours a day) before they start losing their mojo. Plan accordingly.