[Boatanchors] 120 - 240vac and output

[Vic Rosenthal]

Gary Schafer wrote:

> 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. 

But keep in mind that the reduction in plate voltage due to primary voltage drop 
will be FOUR TIMES greater on 120V than 240V.  The primary voltage drop will be 
twice as great, since the current is double (given the same wire size, etc.). 
Since the transformer will need to multiply the voltage 2X more, the drop will 
be 4X what it was.  If you have a 120V circuit using no. 8 wire going directly 
to the service entrance, the effect will be much smaller; but most 120v circuits 
are not like this.

This explains why people say they get 1200 watts with 240 V and only 1000 watts 
on 120, for example.

-- 
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco