[1000mp] Linear Amplifier Recommendations for Use with FT1000 Mark V

[Tom Rauch]

> ran the lines myself from the service panel to the operating desk. 
> With a 220 line you have many more options for amps and they'll run
> more efficiently. --

TIt iss very true you have a wider choice of amplifiers, but an 
amplifier neither runs cooler nor better internally because of a 
switch from 120 to 240. That is a common rumor, but untrue. 

A switch from 120 to 240 can improve power line related problems, 
and often is worthwhile because you can use a wider variety of full-
power amps.  

The reason the amplifier neither runs cooler nor better inside is 
easily understood. Virtually all dual-voltage amplifiers have two 
primary windings. When it is wired for 120, each primary has 
**exactly** the same current as when the PA is wired to operate at 
240. Since the windings are the same windings, and since they 
have the same current, the loss in the transformer is exactly the 
same.

However, at 120 current into the amp doubles while voltage is half 
(the two windings in the amp are in parallel instead of series). That 
means any power line voltage drop is four times larger as a 
percentage of available voltage.There can be a noticeable difference 
in voltage drop between the amplifier and breaker box, and breaker 
box and the power pole transformer. If you have small wiring or 
somewhat long wires, the voltage regulation can noticeably improve.

Personally, I'd never change anything at the kilowatt output level or 
less unless I had a house with older wiring. At 1000 watts or more 
output, especially on CW, a change is often necessary.


73, Tom W8JI
W8JI@contesting.com