Topic: Microtrack and line levels

[yousef]

<bump>

Can no-one help me with my balanced inputs question?

 

[Church-Audio]

Speaking of the balanced inputs, I notice that Soundpros' MT adaptors use standard mono jacks:

http://www.soundprofessionals.com/cgi-bin/gold/item/SP-MICROTRACK-MINI-TRS#
http://www.soundprofessionals.com/cgi-bin/gold/item/SP-MICROTRACK-INTERFACE

I'm presuming that there must be some issue with plugging an unbalanced cable into the TRS input but I'm not sure exactly how these things work - can anyone explain for me? As I understand it, the 'balancing' involves two out of phase signals, one of which is inverted at the destination. So if you plug a mono 1/4" jack into a balanced TRS socket, the same signal goes to both tip and ring components of the socket, one gets inverted and then they are added together = some sort of phase cancellation?

If this is the case, (i) shouldn't clipping when using the MT's 1/4" inputs be less likely when using an unbalanced lead and (ii) why are Soundpros using the mono jacks?

I'm really very confused now - someone please put me right...

When you want to plug in an UNBALANCED audio input for example a 3.5 mm stereo jack is Unbalanced audio. You need to short out the RING with the Shield or barrel of the 1/4 connector.. So sound professionals uses a mono jack this shorts out the ring with the shield thus making it unbalanced. So there are no issues with this method Like I said before you can expect in some cases a net loss of 5 db or so by unbalancing the input of  balanced input. This is not a big deal. I hope this makes sense. If you were for example connecting a 3 pin microphone * that was balanced*  You should use a stereo 1/4 jack the  positive signal pin from the mic pin #2 would go to the tip of the 1/4 inch jack. The Signal negative from the microphone pin #3 would go to the RING of the 1/4 jack and the Shield or ground of the microphone pin #1 would go to the shield or barrel of the 1/4 jack. But for unbalanced we only have a signal out and ground. So we short the ring to ground on the 1/4 jack * we can do this using a mono jack or a stereo jack and shorting out the pins. That's it

So if your using an unbalanced preamp or microphone you MUST short the ring of the 1/4 connector to the ground of the 1/4 connector. So that you unbalanced the audio input on the Microtracker..

[yousef]

Cheers Chris - I think I've got it now.

Hey - my 50th post! I'll go and dish some +Ts out