I've harvested these little Peerless 4859s out of 167x mixers in the past. They are good sounding little inputs. But their max level is a bit lower than the 2622. It's been years, but my notes show max ratio of 1:10.
But I pulled out a couple that I still have, and I mine don't have the primaries in series coming out of the can. I have split windings on both primary and secondary.
You should have two groups of 3 pins on each side. If you lay the transformer down pins up with primary on your left, the bottom left two pins (the two closest to you) are one primary winding (DCR= ~13 ohms). Move to the group of 3 pins above that, and the bottom two of the group is the other primary (DCR= ~13 ohms). The top left pin is the shield (sometimes soldered on the inside of the can, sometimes on the outside of the can).
The secondary is laid out the same way on the opposite side - bottom right two pins are one secondary winding (DCR= ~750 ohms). In the group of 3 above that, the bottom two pins are the other secondary (DCR= ~750 ohms).
This gives you two primaries and two secondaries to work with, and thus you have several configurations possible.
As for your question about your measured DCR "calculating" to 1:8, it doesn't work that way. "1:8" is an impedance ratio (or a winding ratio, not sure which you think), not a DCR ratio. DCR ratios may or may not agree with impedance ratios, as the DCR is only the resistive part of the impedance and doesn't account for the inductive reactance. We often estimate impedance ratings in audio transformers by multiplying the DCR times 10. So, from the measurements detailed above, each primary winding would be estimated to be about 130 ohms (likely a nominal 150 ohms as that's a conventional winding nominal impedance for mic/line transformers) and each secondary would be estimated at about 7500 ohms nominal. But these are just estimates and can be off by quite a bit.
Even so, the 10x estimation approach is still useful for making educated guesses at characterizing an unknown transformer.
If it's a 1:8 or 1:10 winding ratio you're looking for, impedance ratio is proportional to the square of winding ratio.
IIRC, the 2622 was 1:10.
March 24, 2006, 01:07:31 AM
