[R-390] Re: Line filter issues?

[AdamAnt316@aol.com]

Here's yet another update on this set of experiments. With the dimmer switch 
either all the way up or all the way down, and as many other 
interference-producing appliances as I could locate around the house turned off, I still appear 
to be getting line noise. For the most part, it has been quieter than it had 
been recently, but nowhere near as quiet as it was a few days ago before the 
buzzing began (examples of older recordings vs. recordings I've made since the 
buzzing began available upon request). I did some more recording of the sound 
levels coming from my radio on the 900KC oldies station (WSNH), and also 
monitored how much base noise I was getting under the music levels using the line 
level meter (mainly using the dots on the lower scale, not the VU portion). For 
the most part, with the line meter control set to 0 and the line gain control 
set to 4, the base noise level was 25, and the music averaged around 75 
(quieter portions sounded noisier, while portions with peaks near 100 were not as 
noisy). I did get some bursts of band-swamping interference levels similar to 
what I had been receiving previously, one of which lasted a few minutes, while 
most lasted a second or two (none of which could be attributed to the dimmer 
switch, since it was either all the way up or all the way down all of the 
time). In later parts of the recording, noise levels subsided to half their normal 
line level meter readings for unknown reasons, but did not go away completely. 
As far as noise levels go, the noise received was loudest in the following 
ranges: 1100-1700KC, 1800-2400KC (noise levels often reached the 100 mark in 
this range), 3400-4300KC, 4400-4900KC, and some not-quite-as-loud portions on the 
5000KC band. Frequency ranges in between the loud portions listed were 
usually quiet, but sometimes with white noise bursts occuring every 4.5 seconds 
(even on the 7000KC band). I still think that something is not right with my line 
filter, since I only get the interference with the 390A plugged in, and not 
just from the variac alone. Do you think I would have luck replacing the one in 
my set with one from Fair Radio or American Trans-Coil? Alternatively, does 
anyone in the group have any working spares they might be willing to sell to me? 
TIA.
-Adam

Adam Vaughn 
Collector of old computers, video game systems, radios and other electronic 
equipment... 
Visit my page at
http://www.angelfire.com/ma2/AdamVon/index.html


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