[Milsurplus] What's With 2,000 Volt, 50-Watt Xmtrs??

[Bruce Gentry]

Peter Gottlieb wrote:
> In what way is the sound different when using higher voltage?  In transmitter 
> usage, is there any measurable difference in the output signal between the two 
> types?
>
>
> On 11/18/2010 6:49 AM, Bruce Gentry wrote:
>   
>> I  make a guess the early oxide and thoriated tungsten filaments  could
>> not handle higher current densities.  Older AM broadcast transmitters
>> used about 5000 V. for a 5 KW. and  18,000 for a 50 KW.  I have a couple
>> Western Electric audio amps that use push-pull  211s  and 845s with
>> about 1000 V. on the plates. The 211s give 15 watts and the 845s about
>> 65 watts.  I strongly prefer the sound of audio amps using high plate
>> voltages at modest current over lower voltages at high current.
>> ______________________________________________________________
>>
>>     
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> I don't know of any measurable and practical difference in the performance of transmitters except the high plate voltage circuit seems more tolerant to a poorly matched antenna. In audio, the difference can be striking to many listeners. The articulation, realism, and clarity is far better. Music sounds very warm, alive, and clear. For communications transmitters, especially large homebrew AM rigs, there is some benifit as well. Triode modulators at high voltage tend to sound much clearer.  There is a very real competition among transmitter builders to achieve a rich,full sound. One friend's deep  voice is easier to understand because it won't be raspy, and my higher voice comes through bright and clear without being strident. You can more easily recognize voices rather than simply hearing and understanding the message, which makes a net more pleasent when the bands are good. All of these effects are influenced by the hearing and personality of the listener.    
      Bruce Gentry,   KA2IVY