All about electronic valves and hi-fi
Wiring job is done. The fixed bias supply delivers from +50V to -300V. It has more voltage capability as am planning to use this same supply for future builds (e.g. 845 SE). The filament supply set to minimise power dissipation on the filament regulators for the 300B. All working fine, so am happy with this board. Filament noise is 0.3mV.
Slowly making progress during the lockdown period. Over the past few weeks I managed to achieve quite more than I was expecting. The fixed bias and 300B filament supply board (board 1) needs to be wired. On the other hand, the driver filament supply plus the HT supply board is completed (board 2):
I tested the HT supply and can deliver over 430V. It has more voltage capacity, however the filtering capacitors are 450VDC. The DHT filament supplies can do 8V to 15V to accommodate different filament requirements (including some level of filament bias). It works beautifully!
Surely you’re as tired as I’m with COVID-19. One of the best things I can do to distract my mind is to keep myself away from social media. Every stone you turn, there is COVID or a statement about it. I won’t moan as I have a job for now and a healthy family. Some members of my family were infected but nothing major. I can only say is that the world has change. And so my day to day life looking after the young family whilst working is a real challenge. Starting my fifth week of lockdown, I have to distract somehow my mind at times, otherwise will go mad.
After some further efforts, I managed to complete the power supply. And it works, which is always rewarding when you get it right first time:
Here are some picture of my slow progress on this flexible power supply. I started with the layout of the parts before any marks were made on the top plates:
Once I was happy with the layout, I submitted myself to the mercy of the most dreadful job on earth which is metalwork!
