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Old 20th Dec 2004, 6:35 am   #2
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Default Re: Battery eliminators

I assume portable means battery receivers? If so the HT would propably be somewhere between 90-120 and LT at 1.5v. These voltages (originally) supplied by two seperate batteries apeared instanstaneously when the set was switched on. The filament voltage always appears immeditaly on the vast majority of of battery receivers I've seen - and propably also true for 6.3V. filaments in paralallel.

Battery eliminators from the fifties used early solid state diodes even in sets such as the Akkord which came with its own transformer for 90 and 1.5V had a switch at the back of the set and gives HT immeditaly.

Not sure exactly but I believe the "Warming up" time of the regular Dx xx type 1.5 battery valve is literaly a couple of seconds. I don't see any reall benefit for gradual HT, I do have a couple of circuits using a EL33 (could be considered a sacrilige for this valve) and another a EL81 for use as a battery elminator if you would like to try them out.

Apart from over running the filament of I don't believe that any damage can occur from immediate HT and LT in portable sets - even if there is the battery valves are so cheap and pleantiful.


Last edited by valvecollector; 28th Dec 2004 at 9:37 pm.
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