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IK0VNQ > OLDSET 24.07.09 08:39l 35 Lines 1250 Bytes #999 (999) @ WW
BID : O7JIK2XDE021
Read: GUEST
Subj: Re^2: G4UEQ > hum bucking
Path: IZ3LSV<IK2XDE
Sent: 090724/0738z @:IK2XDE.ILOM.ITA.EU [Italy] obcm1.07b3 LT:999
From: IK0VNQ @ IK2XDE.ILOM.ITA.EU (Filippo)
To: OLDSET @ WW
X-Info: Sent with login password
From: G4UEQ@GB7SYP.#19.GBR.EU
To : OLDSET@WW
>Hi Warren and all,
>
>I remember when I started in the radio and television repair workshops as
>an apprentice some of my elders mentioning that on the old radios the
>valve heater line went o/c when the speaker was disconnected, so I knew
>that the heater wiring went round the speaker and I assumed the speaker
>winding needed the 6.3v, or whatever of the heater line.
>
>73,s de Terry,
>G4UEQ.
.............................................................
Hi Terry, Warren and all,
clear enough what was the trick to eliminate hum from the speakers in old
radios, I didn't know it before! In old times I had to replace an output
transformer from a radio built soon after WWII but I remember that the
secondary winding went straight to the speaker coil, no other line was
connected to it. If there was any hum in those radios, it was too low to
be heard at a normal volume level. The speakers in those radio didn't have
permanent magnet yet.
Thanks for the topic gents! I learnt something.....new!
73 del Filippo
IK0VNQ @ IK2XDE
>>> GREETINGS FROM THE ROMAN CASTLES, LAND OF WINES <<<
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