[Amps] 60 filament noise

[StephenTetorka@cs.com]

Simple question: regarding my "audio having hummmm" and my 204A is being Heising modulated with an 839...presuming this hum is AC..and this AC is associated with the tube(s) filaments...

How is the 60 cycles being conveyed?

By 'AC modulation' of the tube ion flow to that plate?
By actual physical vibration of filament wires from the 60 cycle 11 volts?
other?

Thanks guys.

Rookie Steve
WA2TAK

"R. Measures" <r at somis.org> wrote:

>
>On Feb 6, 2006, at 10:18 AM, StephenTetorka at cs.com wrote:
>
>> Hi Rich:
>>
>> Please excuse me for not providing more detail.
>>
>> I made a 1929 Hartley using a 204A Heising modulated with an 849.
>>
>> Both tubes are filament heated with 11 VAC @ 5 amps wiht center tap on
>> 204 for keying..or plate on during AM...ct on the 849 for 'modulation
>> control'....
>>
>> In one QSO, I was told there was a little hummmmm on the
>> signal..otherwise good.
>
>DC is okay for heater-type tubes, but for filament types, it is
>problematic.
>>
>> I'd like to have just 'good.'...hihi
>>
>> R,
>> Steve
>> WA2TAK
>>
>>
>>
>>
>> "R. Measures" <r at somis.org> wrote:
>>
>>>
>>> On Feb 6, 2006, at 7:36 AM, StephenTetorka at cs.com wrote:
>>>
>>>> Hi all:
>>>>
>>>> Might it be possible to apply a high-pass filter to eliminate the 60
>>>> Hertz ac
>>>> power supply noise from getting into my filaments?
>>>>
>>>> Also..it is my understand that using a DC filament voltage works just
>>>> as well
>>>> as the AC...correct?
>>>
>>> For heater-type cathodes or filament-type cathodes?
>>>>
>>>> Regards,
>>>> Steve
>>>> WA2TAK
>>>> _______________________________________________
>>>> Amps mailing list
>>>> Amps at contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/amps
>>>>
>>>>
>>>
>>> Richard L. Measures, AG6K, 805.386.3734.  www.somis.org
>>>
>>>
>>
>>
>
>Richard L. Measures, AG6K, 805.386.3734.  www.somis.org
>