thedug
Well-known member
- Joined
- Jun 13, 2004
- Messages
- 235
I wired up some api 325 line cards as mic preamps.
Anyway, I racked these up awhile ago and was just checking it out on my scope. I noticed that pin 3 on the output is always 1/2 the voltage on pin 2. Is this right?
I basically wired the 2 top winding in parallel. Since this is an inverting amplifier, pin 2 is the botton of the winding and pin 3 is the top of the winding. So.. yellow & green tied (11&12) and pin 2 = 13 (blu) and pin 3 = 10 (orange).
This may just be indicative of my lack of knowledge of how to use a scope, but if I probe pin 2 then pin3 I see about a 1/2x drop in voltage.
I used these diagrams when I originally wired them up.
API 325
http://www.danalexanderaudio.com/ApiInfo/api325schem.jpg
API 312 (I used this as a reference for turning the 325 to a 312)
http://www.danalexanderaudio.com/ApiInfo/api312schem.jpg
Doug
Anyway, I racked these up awhile ago and was just checking it out on my scope. I noticed that pin 3 on the output is always 1/2 the voltage on pin 2. Is this right?
I basically wired the 2 top winding in parallel. Since this is an inverting amplifier, pin 2 is the botton of the winding and pin 3 is the top of the winding. So.. yellow & green tied (11&12) and pin 2 = 13 (blu) and pin 3 = 10 (orange).
This may just be indicative of my lack of knowledge of how to use a scope, but if I probe pin 2 then pin3 I see about a 1/2x drop in voltage.
I used these diagrams when I originally wired them up.
API 325
http://www.danalexanderaudio.com/ApiInfo/api325schem.jpg
API 312 (I used this as a reference for turning the 325 to a 312)
http://www.danalexanderaudio.com/ApiInfo/api312schem.jpg
Doug