jackinthebox said:
see attached pic. the T47 spec sheet shows the pins labelled A,B,C,and D. As does the PCB, but it is a bit confusing which pins are which on the transfomer itself. Pin A is the one closest to the 'T' in T47 on the pins side of the transformer.
Hope this helps!
Hello Friends and Neighbors...I realize I am a year and a half late to this part of the conversation, but I am running into a similar situation as another person here. It would appear their solution was to wire in the T47 rather than use the pins as some others have. Hopefully Jackinthebox will see this or anyone else who has used the T47 from AMI. In this post the quote is discussing the orientation of the pins (A-B, C-D) The information regarding the orientation of the pins (A-B, C-D) is not the way I was told it is from AMI on this transformer. I attached the picture I was sent from AMI showing which pin is which. This picture appears to be reversed from the information given from "jackinthebox". I initially thought AMI had marked the picture incorrectly for me because all the transformers in the images from "vintagemicrophonepcbkit.com" have the transformer attaching/mounting onto the capacitor side of the PCB not the tube side. I went ahead and soldered the transformer on the board on the cap side and realized the body didn't fit over the transformer the way I had the L brackets connecting to the ribs of the body...so then I thought "oh, ok I get it. AMI did not label the picture wrong , the transformer simply connects on the back (tube) side of the PCB." once I did this-sure enough the body fit just fine, the letters lined up perfectly on the PCB with the picture AMI sent me and I assumed it was all good.
I finished the microphone (also, I apologize but I built a D-47 and not a DEF47, but the boards appear to be laid out the same apart from the tube configuration) so I finished the microphone, kicked it on and it worked just fine. Very, very low noise and sensitive. Nice hot signal and zero buzzes, hums or anything to imply a mistake. The confusion is the orientation of the letters as they correspond to the PCB. I looked closely at the board and as far as I can see the letters are exactly what they should be...the A pin runs to P+, the B pin runs to P- etc so I know the lettering on the PCB is where it should be its simply a matter of which pin is which on the transformer.
My question is how did you come to the conclusion that "Pin A is the one closest to the 'T' in T47 on the pins side of the transformer" as the information I received from AMI indicates that pin is "B", and it would seem after looking at your photo and your post I did it wrong. I'm new to this, this is my first build. but I'm not new to electricity. DC typically doesn't work backwards, AC does, but not DC. Again, I am new here so my logic could not matter at all. I honestly just want to do it correctly. I don't want to power on the microphone until I confirm the orientation of the transformer pins. I am so sorry for the long rant I feel like I need to explain myself to make sure people understand my question. Also to be clear as well...this is NOT a mic and mod kit! I purchased this board set from vintagemicrophonepcbkit.com and my body came from sudio939. So anyway, thanks everyone. If anyone has any insight into this I would really appreciate it. I am not trying to be arrogant or rude or anything like that. I am genuinely grateful for everyone here always helping each other and hopefully can help me too
