Battery powered tube radios.

[jr_tech]

WA2ISE...
Interesting Garod with the 117Z3 rectifier instead of the usual selenium! I recall seeing a portable set that used a 117L7/M7 to provide DC power and also as an audio "booster amp" when operated on line power. Anybody recall such a circuit or remember the model?
jr

[Telecolor 3007]

Can you still find 45 V and 90 V batteryes and accumulators?

[Jeffhs]

Originally Posted by Telecolor 3007

Can you still find 45 V and 90 V batteryes and accumulators?

You will have a difficult time finding them, as these batteries have been out of production for decades. The 90-volt B+ (plate voltage) supply, however, can be obtained by snapping ten (five for 45 volts) 9-volt transistor batteries together, and the filaments can be powered by heavy-duty 1.5-volt alkaline flashlight batteries. The C (grid) supply, if required, can be one or two 1.5-volt heavy-duty alkaline cells.

I'm not sure what you mean by "accumulators", but if you are referring to battery eliminators, I'm sure a suitable one can be constructed from plans in old electronics magazines (Popular Electronics, et al.) and amateur radio magazines such as QST. Note, however, that the battery(ies) used for the B+ supply will last a long time, since the tubes in battery radios don't draw much plate current. Expect to replace the filament batteries more often, as the filaments in these tubes draw much more current than the plates; however, the actual life of the filament battery(ies) will depend on how much the radio is used. Many AC/DC/battery radios had a small flag on the tuning dial or elsewhere on the cabinet, mechanically linked to the power switch, that would indicate whether or not the radio was turned on. This flag supposedly prevented (or at least minimized) situations in which the radio was accidentally left on at very low volume all night, resulting, of course, to the owner's surprise, in very weak or even dead batteries when the radio was switched on the following morning.

[jr_tech]

Originally Posted by Telecolor 3007

Can you still find 45 V and 90 V batteryes and accumulators?

At least 45V and the very popular 67.5V sizes still are available new:

http://batterycountry.com/ShopSite/specialty-cell.html

(not affiliated)

But they are quite expensive, so I mostly use 9V batteries in series, as required. In this little Emerson, I crudely stuffed about 72 Volts of 9V batteries inside an older cardboard sleeve.



One poster here "Batterymaker" puts together nice authentic-looking reproductions.


jr

[dieseljeep]

Originally Posted by jr_tech

WA2ISE...
Interesting Garod with the 117Z3 rectifier instead of the usual selenium! I recall seeing a portable set that used a 117L7/M7 to provide DC power and also as an audio "booster amp" when operated on line power. Anybody recall such a circuit or remember the model?
jr

The Emerson model FU424 was one of several sets of that design. Riders vol. 13.