Quote:
Originally Posted by dave walsh
4 AMPS for heaters, post 49*, seems a lot by later standards.........
Dave W
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Dave,
for clarity I will list the actual heater currents for the valves the R1155 contains. If 4 amps "sounds a lot" - its a good bit less than the 4.7A that is the "official total" when all the valves are fitted. Here's how that breaks down:
Receiver section:
V3 RF amplifier VR100 Ih=0.3A
V4 Mixer/Local oscillator VR99 Ih=0.3A
V5 1st IF amplifier VR100 Ih=0.3A
V6 2nd IF amplifier VR100 Ih=0.3A
V7 Detector/AGC/audio VR101 Ih=0.65A
V8 Audio output VR101 Ih=0.65A
V10 Tuning indicator VI103 Ih=0.3A
Total heater current receiver: 2.8A
DF section:
V1 DF Switching VR99A Ih=0.3A
V2 DF Switching VR99A Ih=0.3A
V9 Visual meter switch VR102 Ih=1.3A
Total heater current DF: 1.9A
So.....the "4A heater current" is in fact incorrect - its 2.8A if the DF valves are removed, and 4.7A if they are fitted. Someone wanting to just use it in comms mode, could get away perfectly well with a 3A LT power source.
The valve compliment in the receive section is about average for a WWII receiver. The DF section is unusual and adds nearly another 2A- which is probably why most users of the set have routinely discarded those valves. Its only with the push for authenticity in recent decades that people have started to grapple with the full system.
Richard