Geoffrey S. Mendelson wrote:
wrote:
what exactly are "12 volt 6146B's" ?
6146B have 6.3V heater. What tube are you using exactly?
There were several variants with different heater voltages. I once
bought a bunch of them cheaply at a hamfest. If you were building
your own rig and could set the heater voltage, they were well worth
the price.
In a commerical radio, e.g. the 820, they were of absolutely no
use.
Geoff.
The tubes in Question are a pair of 6883B's. According to all my data
they are identical to the 6146B except for a nominally 12.6 volt
heater rating, and a tiny increase in interelectrode capacity (about
1%). They were often used in high power (~60 watt) HF "bush" radio
telephones in NZ until recently, both in SSB and AM modes.
So they are relatively common here.
I pulled the covers off the final to check after your posting.
Since the 820S actually runs the 6146B heaters in series from 12.6 volts
there should be absolutely NO reason why they couldn't do the job with a
simple heater rewire from series to parallel.
They are physically identical to a 6146B externally.
Hope this clarifies the situation.
Regards Cliff Wright ZL1BDA