[Hallicrafters] SX 101A hum: how much is too much?

[Patrick A. Thompson Sr.]

I read Glen Zook's (k9sth) comments before posting and my opinion is that
his comments are accurate.

Unless you have heater to cathode leakage replacing tubes will not help.

You might want to pad down the line going to your phones so that a greater
audio gain is required to provide normal listening volume.  In this manner
you can push the hum level down in relation to the desired audio. Padding
then increases the audio signal to noise/hum ratio.

It may be possible to add a resistor across the phone jack so the radio is
not modified.

Pat, wa4tuk

-----Original Message-----
From: hallicrafters-admin at mailman.qth.net
[mailto:hallicrafters-admin at mailman.qth.net]On Behalf Of Andy Bullington
Sent: Sunday, January 25, 2004 5:30 PM
To: hallicrafters at mailman.qth.net
Subject: [Hallicrafters] SX 101A hum: how much is too much?


After getting my SX 101A all back together and installed on my operating
bench, I got a mono adapter for my headphones and noticed ....hum!! At all
or no volume level, all or no rf level...doesn't seem to make a difference.
I never noticed it through the speaker but after discovering it in the
phones, I put my ear right in the speaker and there it was. Now I've
replaced all the filter caps and all the tubular caps. The only thing I
haven't changed out are most of the tubes. The rectifier and voltage
regulator are coppertops. Any ideas where to look? I'm waiting on a shipment
of NOS tubes but something tells me thats not the problem. Or is this just a
fact of life with old tube receivers? Thanks.
                     Andy W1AWB


_______________________________________________
List Administrator: Duane Fischer, W8DBF **for assistance**
dfischer at usol.com
----
Hallicrafters Collectors International: http://www.w9wze.org
----
http://mailman.qth.net/mailman/listinfo/hallicrafters