Step right up here folks and watch how Shuguang makes a 300B triode output tube! The factory can make 60 regular or 30 of the Treasure Series per day. Only four employees have top level skills to make the Treasure Series tubes.
Inspecting the assembly.
Attaching outer carbon-coated plate element.
One both plates are installed, they carefully solder the plate pieces together.
As for small signal tubes and how they get their sey nipple top, if you remember yesterday's factory tour you'll recall that a 'drink straw' glass tube that is used to aid in forming the vacuum. Well, here is how they removing the top 'drink straw' of a small signal tube.
At the top of these tubes is aluminum and barium. Have you ever wondered how they get that silver-colored top on the inside of the glass?
So they heat just the top of the tube through extremely high voltage 400 degrees Celsius electric/magnetic field and this causes the top silver coating to form on the tube's glass surface. Did i mention this is extremely high voltage and i had to get very close to capture this photograph? They asked me to be very careful getting the above photos due to the obvious danger involved. Below is the after and before product.
If the tube goes bad, this silver coating turns white as seen above.
Box of gold pin tubes.
So where does Shuguang get their gold and silver plated wire. They make it themselves! As you can see above, the right spool is silver colored and as it goes through a brief process where gold evenly forms on the wire and it is gathered on the left spool.
Gold-plated wire anyone? The wire is made of molybdenum and then it goes through a process where a 10µm coating is formed on the wire. The factory uses 20 grams of gold per day to make this wire (a troy ounce of gold is 32.15 grams). Two grams of gold makes approximately 1000 meters of wire. So why gold or silver coated wire you ask? For heat dissipation mainly and of course to reduce corrosion and ensure uniformity.
The gold wire is wrapped around copper posts to make the grid.
Here they are shaping a silver plated wire grid and one operator makes 3000 of these per day.
Coating of the cathode.
Hair-thin Tungsten wire coated with aluminum oxide is being prepared for a very special coating process.
After this coating the wire is heated to 1700 Celsius, the aluminum oxide becomes hard like ceramic.
Many tubes go through an eight hour burn in process on the racks. This room had at least, well... i lost count yet must be 1000+ tubes going at a time on many rows of racks (only one of the many are pictured here).
Shuguang is a very large facility and it almost boggles the mind how many tubes that can manufacture each day. Was impressed how efficient and fast everyone was able to get their task completed as tubes went through each step of the manufacturing process. This is one of those once-in-a-lifetime tours that i'll always happily remember when i use Shuguang tubes in my equipment.