Carnhil VTB9045 (10468) Microphone Input transformer. What ballpark resistance should I be seeing across XLR pins 2 and 3?

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

777funk

Well-known member
Joined
May 7, 2009
Messages
166
I'm getting around 30 ohms and it's dropping my phantom power from 52VDC to 40VDC (via a pair of 6.8k resistors feeding XLR pin 2 and 3). Is 30 ohms a normal input resistance on this transformer?
 

Attachments

  • Screenshot_2022-06-29_13-18-31.png
    Screenshot_2022-06-29_13-18-31.png
    373.3 KB · Views: 15
yes. I assume your mic load is what's actually dropping your voltage, also normal.
 
The transformer doesn't load if connected correctly. You're sending identical 52V to both sides of a floating winding, there's no load. Impossible to know from the evidence.
 
The transformer doesn't load if connected correctly. You're sending identical 52V to both sides of a floating winding, there's no load. Impossible to know from the evidence.
Yes you're right. I hadn't looked at a mic input transformer schematic in a while. Not sure why I have a voltage drop without a mic connected. Will need to investigate a bit.
 

Latest posts

Back
Top