Api 312 input transformer question
« on: October 01, 2020, 10:01:10 PM »
Hi all

Just in case the old thread is TOO old, I found some scans and a pdf of an API 312 and, forgive me if this is a stupid question but, it has 6 holes for the input transformer but most available options have 8 pins.
Please can someone let me know what I am missing...

Thank you!


Khron

Re: Api 312 input transformer question
« Reply #1 on: October 02, 2020, 01:06:38 AM »
I'd be willing to bet the 8 pins on the transformers are four separate windings. The 6 connections would likely be 4 for the ends of the primary and secondary, and the remaining 2 for the center taps of the primary and secondary.

Comparing the schematics to the circuit boards would easily confirm that.
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john12ax7

Re: Api 312 input transformer question
« Reply #2 on: October 02, 2020, 03:08:46 AM »
8 pins is a common package type,  but that doesn't mean all 8 are actually used.  The main thing is to have each connection go to the proper place.

Walrus

Re: Api 312 input transformer question
« Reply #3 on: October 02, 2020, 05:21:10 AM »
The original API 2622only has 6 pins.
Kevin.

Whoops

Re: Api 312 input transformer question
« Reply #4 on: October 05, 2020, 09:45:06 PM »
Just in case the old thread is TOO old, I found some scans and a pdf of an API 312 and, forgive me if this is a stupid question but, it has 6 holes for the input transformer but most available options have 8 pins.
Please can someone let me know what I am missing...

The 2 Pins diference are probably the Case/Shield and the Electrostatic Shield.
The Capi2622 , Ed Anderson 2622 , Avdo TR2622 and Cinemag CMMI-8APC all have 2 separate pins for Case/Shield and the Electrostatic Shield.


On the Schematic Walrus posted of the 2622 the Electrostatic Shield is connected to case and then both connected Pin4.
Maybe internally connected?


 

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