China Grand Tour 2009
TJ Full Music Tube Factory
Report By Steven R. Rochlin
Now it is time to
make the glass for the vacuum tube. Here is an operator that starts out with a
very long piece and cuts it down to the appropriate length. After cutting the
tube they heat it up to make it easier to separate it.
As it is time to build the lowermost section of
the tube, flames heat up glass and the forming begins. TJ Full Music's new
6SL7 and 6SN7 'coke' or 'shoulder' shaped tube bottom section is what
you see here coming to life so it is time to heat it up to make the glass more
pliable, then they make sure by hand they are symmetrical.
This is how they build the mesh on for the 6SN7 and 6SL7.
Once the long bits are in place it is time to heat it all up to seal the
assembly. Below is the finalized product.
Back to the small signal tubes, while i was watching the tubes dancing around within the machines and the glow of the tubes changing my mind kept thinking the Kraftwerk song
"The Man-Machine" would be the perfect soundtrack. Does this make me the creative type or just one sick
This is the vacuum stage of a small signal tube
(12a-series, etc). What you are seeing above is that the tube's grids and pin
structures are all in place, yet at what is the normal top of the tube is a
open glass 'drink straw' where it allows this machine to being the vacuum
stage process. i truly made the company employees very nervous as there is
a lot of
very high voltage within this machine yet i was insistent at getting close-up
photos so you can see this operation in good resolution as it happens fast.
Besides, it is not the voltage, it is the amperage that would kill me. i've
literally tasted 20 Amperes a few times in my life. Anywho, at first it is a blue glow due to carbon dioxide, and then as it properly seals as a vacuum the blue glow disappears.
Once the vacuum operation is complete they need
to remove the 'drink straw' glass structure, thus sealing in the vacuum and
the tube assembly is complete. Now comes testing and quality control.
This is the first test of the finalized tube where it goes through a few stages from shorting to microphonic problems as the operator will tap the tube with a small wood
mallet. Obvious problems are sorted out here and bad tubes culled out
Once it passes the first round of tests, this testing station checks the electrical parameters of the tube.
And now please allow me to be the first to let
you in on a special world premiere of TJ Full Music's upcoming KT88 output tube.
This new tube will use a very special carbon plate, something which has never
been done for the KT88! So remember you saw it and heard about it here first on Enjoy
Alas, could not visit the other factory site as had to catch a train and plane to my next destination of the China 2009 tour. Fortunately, a gentleman and audiophile I just met named Craig went to the other factory and e-mailed me the below photos.
Click here for the main China
2009 tour page.