OEP Z21805C - Mic input transformer - Any good?

[elskardio]

Hi,

did anyone test the OEP Z21805C mic input transformer? I'm curious if it performs better than the A262 series.

http://docs-europe.origin.electrocomponents.com/webdocs/0d72/0900766b80d72895.pdf

Thanks

 

[Martin Griffith]

That's a strange front end (P2 of the pdf). I assume the front end of the 5534 is being turned off and the signal is going through the supply rails?

 

[PRR]

> going through the supply rails?

I bet these are the "offset" pins. They are also inputs, but hardly any common-mode range (the '2546s handle that).

 

[joaquins]

  They changed the collector resistors from the 12k inside the 5534 with 1k8 (1k6 counting the 12k in parallel), so I would expect about 7.5x the bias current on those input transistors relative to the internals. That's one way to get away with low turns ratio transformer...

JS