[Boatanchors] Tube filaments

[Carl]

This came around in the just prior to the introduction of mass produced AC 
radios of 1926-27. Earlier AC sets did not use a tube rectifier.

The reason was to prevent anyone inadvertently using a receiving tube in a 
rectifier socket. The 227, 245 and 280 both shared a 4 pin base for example.

When running 6V storage battery power and a vibrator the 280/80 could be 
left in place. Some farm radios could be run on 110VAC, 6 and 32VDC.

Carl
KM1H


----- Original Message ----- 
From: "David Knepper" <collinsradio at comcast.net>
To: <boatanchors at qth.net>
Sent: Thursday, December 03, 2009 12:33 PM
Subject: [Boatanchors] Tube filaments


> Does anyone know why RCA, etc. chose 5 volts for their rectifier tubes and
> 6.3 volts for their receiving tubes?
>
> Just curious.
>
> Thank you
>
> David Knepper, W3ST/W3CRA
> Publisher of the Collins Journal
> Secretary of the Collins Radio Association
> www.collinsra.com
> Join today
>
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