My first post..
![Surprised :o](./images/smilies/icon_surprised.gif)
Surfing around the web brought me to intactaudio. Knowing Dave Slagle by name through friends and ETF, I contacted Dave for some 2K wire-resistors for use at 20mA (for a type '10).
After a few weeks I received them, was struck by their simple "design" and also puzzled how to mount them. My idea -> see attached pictures.
Things turned out fine and sound was definitely better than Allen Bradley (2W) and Mills, just as Dowdy explained. Happy me!
After a few hours playtime one channel started to hum, around 100hz, first at low level, later really loud. Since the preamp, in which they were used, was "new" (beadboard setup) I started troubleshooting. At first I thought the CCS on the heater was the culprit but swapping them left me with the same hum. To be short: I almost took everything apart without any succes...
An email was sent to Dave (who knew how they were used) and he asked if the screws used are magnetic. Yes they were... I replaced them for brass types and up til now (hours and hours later) mr. Hum stayed at home...
Can it be that the screw somehow got magnetized and that due to heating of the wire the bare (soldered) mid-tap of the bifilar wound resistor at a certain point contacted the screw and screamed out in a 100hz manner..?
Dave asked me to post this, so I did (do not argue with the master
![Wink ;-)](./images/smilies/icon_wink.gif)
Thanks, especially to Dave...
Rob