DIY API 312 pres...

[bigwillz24]

Long time no post to this thread... I'm having problems with gain at the moment i've put the cards together. but I think I'm having issues with some of the wiring for either the pot or the input transformer.

 

[rsolinski]

What are you using for your input transformer?
What are you using for your pot as a gain control? remember it is just used as a variable resistor and not a voltage divider.
Did you replace the caps and diodes on the card? are they oriented correctly?
Did you terminate the input transformer to reflect the correct resistance back to your mic?

Cheers,
Ray

 

[bigwillz24]

What are you using for your input transformer?
What are you using for your pot as a gain control? remember it is just used as a variable resistor and not a voltage divider.
Did you replace the caps and diodes on the card? are they oriented correctly?
Did you terminate the input transformer to reflect the correct resistance back to your mic?

Cheers,
Ray

I'm using the Sowter 9820F for an input transformer.


This is the switch or pot...

Rotary Single Pole 11 Position $7.59 1 $7.59 Digikey CT2122-ND C&K 212T0111S332RA GAIN

All other questions the answers are yes I acutally can hear audio and it sounds good. The gain knob just doesn't work.

 

[rsolinski]

How did you implement the resistors on the switch? Using one can be tricky..most folks use a 25k log (audio) or reverse log taper potentiometer..if you mount the resistors right on the switch then the action will be backwards (loudest will be all the way counterclockwise and then softer as you turn it "up")

Cheers,
Ray

 

[Minion]

Have you made sure that you have Mounted all of the Resistors to the Rotary Switch properly and have it wired correctly??

I have a Funny feeling that you are useing the Rotary switch but without the resistors mounted to the Switch.....


Cheers