232 resistor needed?

[ZiggyUK]

Hi,
After restoring my 332 I am now working on an ivory 232.
Got it working beautifully with new cords & transmitter.

Am I right in saying a 232 does not need a resistor as it does not have internal bells & only the bellset (if used) needs a resistor?

I do have a type 26 bellset but I have wired that independently so it can just be plugged into a BT socket with or without a phone, I have added a resistor to the type 26 bellset.

I fitted a rectifier to the 232 but could not find mention of the resister so assume it is not needed.

[winston_1]

The resistors that so many people fit to old bells does very little as the bells are mainly inductive and resistors are resistive. They don't magically change a REN 4 bell to REN 1. I never fit them.

[AC/HL]

The resistor is only fitted if more than one low impedance bell is connected in parallel on a standard line, as this can sometimes result in poor ringing. One low impedance ringing load is fine, and two well adjusted bells will probably be OK too. Officially, low impedance bells were connected in series using the spare links in the wired LJU, which is what the resistor is attempting to simulate, wastefully. This subject can raise hackles though, as it is really a worst case scenario bodge.

[ZiggyUK]

Originally Posted by AC/HL

The resistor is only fitted if more than one low impedance bell is connected in parallel on a standard line, as this can sometimes result in poor ringing. One low impedance ringing load is fine, and two well adjusted bells will probably be OK too. Officially, low impedance bells were connected in series using the spare links in the wired LJU, which is what the resistor is attempting to simulate, wastefully. This subject can raise hackles though, as it is really a worst case scenario bodge.

Thank you so much, that is really useful information.

[russell_w_b]

Originally Posted by winston_1

I never fit them.

Neither do I. The resistance (when measured at ringing frequency) and reactance of a Type 59A bell (300 series; 700 series) are similar, typically 1776.2 + j2085.4 changing to 1776.2-j1451.4 with the ringing capacitor in series. Current increases by nearly 20% as a result of connecting the capacitor.

I've found a bell will work down to 8mA on a peaky magneto waveform and 12mA on a sine-wave.

As I understand it, the 'official' BT series resistor modification was meant for Trimphones with an electronic warbler, rather than magneto-bell instruments.