Hi to all,

Why most of the old radio sets are built with oversized resistors at every places where power resistors is not really required ?
Like 5 or 10 watts.

Even in AGC line which doesn't not carry much current, i sometime see a 2Megs/5 watts !!
1/4 watt would be enough.

Grid bias resistors are also way oversized.

Is it because small resistors were difficult to produce in the 30's ?

Hi

Modern resistors are much smaller for the same wattage. Here is a comparison:

http://www.philcorepairbench.com/resistcompare.htm

Norm

:Hi to all,
:
:Why most of the old radio sets are built with oversized resistors at every places where power resistors is not really required ?
:Like 5 or 10 watts.
:
:Even in AGC line which doesn't not carry much current, i sometime see a 2Megs/5 watts !!
:1/4 watt would be enough.
:
:Grid bias resistors are also way oversized.
:
:Is it because small resistors were difficult to produce in the 30's ?
:
:
:

I've never noticed that "most" old radios use way-overrated resistors. Radio manufacturing in the 1930s was a cutthroat business and radio manufacturing engineers went to great lengths to ensure that the recurring cost (i.e., component cost + touch labor) was as low as possible in order to have competitively-priced sets and to maximize profits. Generally, this meant using the cheapest part that would do the job, and higher-power resistors as a rule were more expensive than lower-power ones.

It's possible that what you are seeing is the result of repairs done over the past several decades since the sets were made, where the repair techs might not have had the original power-rated resistors so they subbed higher-power ones. This is generally OK to do and the small additional cost could be passed along to the customer.