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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => Installed Sound/Contracting => Topic started by: Joseph D. Macry on December 10, 2019, 09:28:39 AM

Title: 25V vs 25VCT
Post by: Joseph D. Macry on December 10, 2019, 09:28:39 AM
What is the difference between 25V and 25VCT speaker output?
The Google is failing me.
Title: Re: 25V vs 25VCT
Post by: Milt Hathaway on December 10, 2019, 11:19:22 AM
What is the difference between 25V and 25VCT speaker output?
The Google is failing me.

Center of page 10 of this old Bogen 70v theory PDF: https://www.bogen.com/support/pdfs/Installs.pdf

I learned something new today. Apparently the 25VCT connection is not a speaker output.
Title: Re: 25V vs 25VCT
Post by: John Roberts {JR} on December 10, 2019, 02:44:46 PM
Center of page 10 of this old Bogen 70v theory PDF: https://www.bogen.com/support/pdfs/Installs.pdf

I learned something new today. Apparently the 25VCT connection is not a speaker output.
I have never seen, or had a customer ask for that feature. I am familiar with lower voltage specifications for school applications.

It appears to be the center tap for the 25v winding that if grounded with common terminal floating provides a balanced output with opposite polarity AC voltage on common.

I would further speculate that with common terminal grounded the 25V CT terminal could be used as a 12.5V tap. If not designed to be used that way I would not expect full power from the 12.5V tap.

JR


Title: Re: 25V vs 25VCT
Post by: Joseph D. Macry on December 10, 2019, 03:36:23 PM
Okay, I get it. "CT" is the center tap of the 25V winding on the output transformer, useful for making balanced output for reducing crosstalk.
I'm asking because I saw this feature on a Bogen HTA-250A amp I'm trying to resurrect.