05-04-2014, 02:29 PM
(This post was last modified: 05-04-2014, 02:36 PM by Radio Fixer.)
The coils look quite workmanlike but I would have given them some physical protection. Probably tape as I find wax dip messy.
I take it that the speaker is not original? Or the cct diag is incorrect and it really should be 300? If it were 3K it would lose about 120 V off the HT (assuming 40 mA drain) and dissipate about 5 W. Possible but not normal. Series fields are usually in the range 300 to 1200 Ohms.
If it were true then you wouldn't want to just wind a coil but use a choke if you want hum suppression ... 10H x 2Pi F (where F is 50 or 100Hz depending on HW or FW) does that. Resistance wont be more than a few hundred Ohms though. You need miles of copper wire to get the resistance you are indicating. So if you want to lose some HT use a series resistor. Metal clads bolted to chassis don't take up much room and lose the heat easily.
But its not easy to be clear here as the info you gave doesn't really add up !!
Gary
I take it that the speaker is not original? Or the cct diag is incorrect and it really should be 300? If it were 3K it would lose about 120 V off the HT (assuming 40 mA drain) and dissipate about 5 W. Possible but not normal. Series fields are usually in the range 300 to 1200 Ohms.
If it were true then you wouldn't want to just wind a coil but use a choke if you want hum suppression ... 10H x 2Pi F (where F is 50 or 100Hz depending on HW or FW) does that. Resistance wont be more than a few hundred Ohms though. You need miles of copper wire to get the resistance you are indicating. So if you want to lose some HT use a series resistor. Metal clads bolted to chassis don't take up much room and lose the heat easily.
But its not easy to be clear here as the info you gave doesn't really add up !!
Gary
