[Boatanchors] 120 - 240vac and output

[Gary Schafer]

Think about this for a minute and you should be able to figure it out 
yourself. The only thing that changes in the amp whether it is run on 
120 or 240 is the primary configuration of the transformer. The rest of 
the amp knows nothing of the difference. Filament voltage is the same 
and plate voltage is the same.

With a however here, The plate voltage may be a little better regulated 
(may not drop quite as much) because of a little less voltage drop on 
the house wiring on 240 volts. The filament voltage in the amp as well 
will not drop quite as much when the amp is transmitting because of the 
slightly less primary line voltage drop. With good 120 volt wiring the 
difference will be small. If you have an extra long run of #14 for your 
120 volt circuit then you could see a marked difference in voltage drop 
on the amp under load. The filament voltage would only drop lower on the 
120 volt circuit.

73
Gary  K4FMX


Ray Friess wrote:
> It will not give the amp more power input or output.   The main reason 
> for 220 over 115 is that
> the amp draws less current.   Do the math ....   P =  I times E.     The 
> higher the line voltage,
> the lower the current to generate the same power...
>     The lower drawn current is claimed to make the tubes last longer ... 
> but I have heard from some
> that it makes no difference on tube life.   A tube is designed to draw X 
> amount of current at a
> certain power level...   A tube has an unknown life span at a certain 
> voltage and current limit, and
> I dont know that using a lower voltage or current is going to lengthen 
> that life appreciably...
> As I've said, I've seen arguments on both sides as well as heard many 
> personal experiences given..
>     I have two 30L-1 linears and an SB 200 ...  all are wired for 115 
> (or 120 if you will) ...
> mostly for convenience because there was already 115 in the room I 
> turned into a shack...   Just
> regular house wiring...
> Ray  wa7itz
> 
> George KB2Z wrote:
> 
>> Thanks for all the insightful replies. I was asking because when 
>> learning electronics one of the first things taught was "theres no 
>> free lunch". I have been casually thinking of another amp and one 
>> thing I often see is "1000W with amp wired for 120. Should do 1200W if 
>> changed to 240". At home I never saw that but did not want to debate 
>> it. I guess my 120 comes from a nuclear plant.
>> Again thanks, 73 George KB2Z
>>
>>
>> At 06:53 AM 11/24/04 -0500, you wrote:
>>
>>> Can someone in the know clear up the question of whether 240vac will 
>>> give an amplifier a power boost over a 120vac line?  This is assuming 
>>> that the 120vac is healthy and can handle the input amperage required 
>>> by the amplifier, (no dimming or blinking) without blowing any house 
>>> fuses or breakers.
>>> Thanks in advance, George KB2Z
>>>
>>>
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> 
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>