Hi!
I have a question about the application of the AES48 Standard when it comes to using two balanced inputs in the same enclosure. In this case the application is that of a re-amp box, thus ground isolation is important.
As per figure attached and the AES48 standard, generally Pin 1 of Input 1 is grounded to the enclosure. If Pin 1 of Input 2 were to be grounded as well, I believe that it might cause noise or interference should Inputs 1 and 2 be coming from totally different sources whose ground is not common.
However is this practice 'safe'? i.e. Is it ok for Pin 1 of Input 2 to not be grounded with the enclosure? As technically Input 2 would not be compliant with the AES48, right?
Thanks!
I have a question about the application of the AES48 Standard when it comes to using two balanced inputs in the same enclosure. In this case the application is that of a re-amp box, thus ground isolation is important.
As per figure attached and the AES48 standard, generally Pin 1 of Input 1 is grounded to the enclosure. If Pin 1 of Input 2 were to be grounded as well, I believe that it might cause noise or interference should Inputs 1 and 2 be coming from totally different sources whose ground is not common.
However is this practice 'safe'? i.e. Is it ok for Pin 1 of Input 2 to not be grounded with the enclosure? As technically Input 2 would not be compliant with the AES48, right?
Thanks!
I would just hook it up as you planned and take for granted that it is not AES-48 compliant.
To make it AES-48 compliant, you would have to connect all pins 1 to each other via the chassis or enclosure. Presumably that defeats the purpose of the signal transformers; I assume you need signal transformers because of ground loop issues caused by non-AES-48-compliant equipment elsewhere.
Also if everything else should be compliant, I don't expect issues when you connect it to this box.
I'm not sure on which side of the transformers the potmeters can best be placed. Placed on the primary side, they reduce the level, which reduces transformer distortion, and increase the driving impedance, which increases transformer distortion.
To make it AES-48 compliant, you would have to connect all pins 1 to each other via the chassis or enclosure. Presumably that defeats the purpose of the signal transformers; I assume you need signal transformers because of ground loop issues caused by non-AES-48-compliant equipment elsewhere.
Also if everything else should be compliant, I don't expect issues when you connect it to this box.
I'm not sure on which side of the transformers the potmeters can best be placed. Placed on the primary side, they reduce the level, which reduces transformer distortion, and increase the driving impedance, which increases transformer distortion.
The best place to start with questions like this is the 30 page book chapter by Bill Whitlock of Jensen Transformers (retired).
Handbook for Sound Engineers, Third Edition
Glen Ballou, Editor
Chapter 11
Audio Transformers
by Bill Whitlock
https://www.jensen-transformers.com/wp-content/uploads/2014/08/Audio-Transformers-Chapter.pdf
* * * * * * * * *
but if both units are AC powered, the shield does not always need to be connected at the receive end.
Handbook for Sound Engineers, Third Edition
Glen Ballou, Editor
Chapter 11
Audio Transformers
by Bill Whitlock
https://www.jensen-transformers.com/wp-content/uploads/2014/08/Audio-Transformers-Chapter.pdf
* * * * * * * * *
but if both units are AC powered, the shield does not always need to be connected at the receive end.