Approx. Ringer Equivalence for SC 1443, 1543, and 1546 sets..

[RotoTech99]

I've run across some SC 1543, and 1546 sets using a SC 74A straight-line biased ringer, or #85 Split coil biased ringer with a. .47 Mf cap. on the ringer frame.... BTW: These are high impdeance, single coil ringers.

I've noticed the "extra" .47 Mf cap is usually for providing sufficient power to sound the ringer because the internal network capacitors aren't strong enough to do it by themselves even if linked.

My question is: What would the approx. ringer equiv. value be for a 1543/1546 using either the #74 or #85 ringer be for a single line bridged ringing setup providing 48-105 VAC at 20 Hz.?

I know the values for other antique sets, and hve the sheets on those, but I can't help wonder what it would be for the 1443, 1543, and 1546 "family of SC phones"...

If someone has guesses or info that might answer this, please accept my thanks in advance.