LA6NCA - 12A6, SI5351 CW Transmitter

I have designed a new transmitter for 80 meter CW.
The oscillator consists of a modern SI5351 and output stage
consists of a tube 12A6.

I just had my first QSO with this nice little transmitter.

It is used here with my R390A receiver.

The whole project started when I got 223 pieces of tube 12A6.
What should I use them for?

Different makes of the same tube.

I want to design a transmitter with both old and new technology.
Modern oscillator and old amplifier.

Here I have started assembling the components.
The Coil is mounted on 3D printed holders.

I wind up the coil on an old capacitor.

I have designed my own capacitor.
It is copper tape glued to Teflon.
This gives a capacitor with a very high Q.
It can also withstand very high voltage.

To the left we see the oscillator fully assembled.
We also see the coil with the 3D printed holders.
And we see the capacitor fully assembled.

Here we see all the small components needed to build a transmitter.

My SI5351 and ATmega328 (ProMini) circuit board mounted in a 3D printed box.
The box looks like an old-fashioned crystal.

SI5351 mounted on the transmitter.
The yellow connector on the right is the Arduino USB programming port.

I am writing software for the SI5351 oscillator.
The small circuit board I have plugged into the oscillator is the USB interface.

The complete transmitter.
We see the oscillator with up / down switch.
The oscillator here also a signal from the key relay.
This starts the oscillator and keeps it running 0.5 sec after key down.
Between the oscillator and 12A6 we have a voltage amplifier circuit with coils and capacitors.
On the far right we see the voltage meter to measure the output signal.