help in identifying/specing mystery iron

hi

i recently took home the carcass of an old mixer that was in a junk room. it's an old 16 channel 'NEI' mixer.
???

it's all ICs inside, but has 16 mic trannys. i have no idea what they are, or if they are any good. they are in a cylindrical can measuring 28mm in diameter and are 26mm high. they have 6 pins and have "P-K 2-1014" printed on the top. they feel like they have a good mass. the only test equipment i have is a multi meter and protools PAZ analyzer PIs.

if anyone is interested in checking one out i would share the bounty if they turn out to be useful.

let me know.
-AL

Hi Al,

Fortunately some of the work here will be done for you already- if you've got the transformers in their original application, you can trace the wires form the mic input connector to the transformer and make a note of the pins. Then trace the secondary to the pre circuit. This will give you the pinouts for them.

What sort of op-amps are we talking about in this mixer, and can you trace out the circuitry immediately after the transformer- you can often second-guess the ratio of the transformer by checking out the following circuitry.

:thumb:

Mark

Hi Mark,

yep, i got the pinouts. so the secondary connects to pin 2 of a TL072 via a 680R and 2 10uF caps in series. i guess this should give us a clue about the secondary impedance, but i don't know how to interperet this. i guess the primary would be somewhere between 150ohms and 1.2kohms.???

so if i send a tone through it i may be able to find out tghe ratio at least right? say 1k @ 50mV?

if i could measure the DC resistance, capacitance and inductance of each winding could i find out the impedance? or are there more complicated factors at work...