[R-390] Resistors, noise, etc.

[Kenneth G. Gordon]

Roy Morgan wrote:

<Among other things...>

> It's the opinion of experienced radio users that very very few of us live in
> places where the received noise level is low enough so that the noise
> generated in a receiver is of much matter at all.  On HF, that is.  Above 30
> mc it's a different matter.

Actually, there are TIMES, even on 160 meters, when the external 
noise level IS low enough to hear receiver noise. However, external 
noise levels ARE getting worse. Back in the late 1960s, I found that 
receiver noise was definitely an important factor at 14 Mhz and above.

> As I understand it, carbon composition resistors are favored by the high fi
> builders for low noise and for other differences they hear in the sound.  And
> they also report that some other resistors are better for noise.

A recent article in ER magazine by Ray Osterwald on the restoration 
and enhancement of the SX-101A covered resistor noise in quite good 
detail. HE says that carbon comp resistors are the noisiest, and has 
data to prove it.

He also discussed capacitors in the same article. This is one of 4 or 5 
articles on the SX-101, and is well worth the read for the information it 
contains which apply to our R-390s.

Ken Gordon W7EKB