of using them as input transformers, be sure you really have a pair.
Similar looking units can be pretty different!
For step up input
transformers (as T41, T42, T110 a.s.o) goes:
- input winding DC resistance is between
3 and 500 Ohms
- output winding DC resistance is between
transformers coming from the same preamp can be different. T41s i.e.
range between 350 and 450 Ohms on the primary and 7.5k and 8.5k on
the secondary windings.
Many transformers have a pair of twisted leads which represent the
In many instances the output winding is a single lead and 3 to 5
leads soldered together (some of these are grounding leads or
connected to the mu metal can). The T41 i.e. usually has 4
leads soldered to ground. See its schematic on the left.
Caution! Many windings are defective. Connecting higher output or active
units to the input transformers many input windings
have been killed. If you do not find a pair of working winding this
may be your case.