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TRS Insert Jack?

PostPosted: Tue May 24, 2005 4:19 pm
by mrosso
Has anyone ever attempted to stick a TRS insert jack between the output of an SCA preamp (N72/A12/J99)? I'd like to go unbalanced from the preamp/CH01 into my FMR RNC compressor and back to the preamp to be sent out the balanced XLR. Is this doable?
Thanks,
M

PostPosted: Wed May 25, 2005 12:15 pm
by sbranco
This doesn't answer your question at all but it may be in the same vein for someone to answer. We are building an N72. Right now we have an RNC, MOTU 2408 MkII and two digimax LT's. The digimax AD converters seem to be better than the MOTU's. We can go unbalanced into the digimax through the return on the digimax insert bypassing the digimax pre. I figured we would come out of the SCA into the RNC then on to the digimax insert. If we get our tip, ring and sleeve connections right, it should work fine, no? RNC website has a page on connections to balanced and unbalanced equipment here http://www.fmraudio.com/FAQ.htm

I re-read your post and I see that you want to intercept the signal before it gets to the SCA XLR out and bring it back in before going out the SCA XLR. Way beyond me but I am sure Tim or others can answer it.

PostPosted: Sat Jun 04, 2005 7:50 am
by Royce
Image

TRS jack for SCA preamps

PostPosted: Mon Jun 06, 2005 8:39 am
by mrosso
Thanks sbranco. Royce, this doesn't work (TRS at the FMR compressor is in-out combo). If it was that easy, I wouldn't have posted the question.

PostPosted: Sun Jun 26, 2005 4:48 pm
by Daedalus

PostPosted: Sun Jun 26, 2005 6:23 pm
by tele_player
No, that's completely irrelevant here, as the current 7th Circle preamps do not have any unbalanced insert points. The earlier rev of the N72 had a location where an unbalanced insert could be added (CONN3, if I recall correctly), but it's not on the newest boards.

PostPosted: Tue Jun 28, 2005 2:07 pm
by Royce
Ok... I guess I'm a bit confused then about what you are trying to do. You want to go In to the Pre... Then out to the RNC. Out from the RNC... Then back In to the Pre... then out to the recorder? :?:

In effect run through the pre - compressor - pre again? Or are you trying to run it like a DI in reverse to convert unbalanced to balanced?

Here's the info from FMR Audio's site for how to hook up different pieces of gear to the compressor.
http://www.fmraudio.com/FAQ.htm

I guess what's trowing me is why you need to run it back to the Pre a 2nd time.

PostPosted: Tue Jun 28, 2005 3:41 pm
by dabo
In regard to the question "is this doable?", the answer is yes. But there are a few caveats.
Since most pieces of gear that would follow a mic pre have some sort of output level control, there is little advantage to be gained by having an insert point in these preamps, that is, except for mrosso's question...
The RNC is unbalanced in and out. By sending an unbalanced line level signal out to such a piece of gear and returning the processed signal to the point in the circuit it was sent from, the advantage of a balanced output from the chain of devices is retained.
The way to achieve this depends on a few other questions:

Which pre amp? (It's easy in two of them, but limited in options in regard to the next question)
Pre or post fader?
How do you fell about risking DC offsets?
How do you feel about coupling capacitors?

My advise is to buy a truely nice (and balanced) compressor.
If you absolutely must have the special magic that only the RNC can deliver, take the hit and follow the advise at the link offered by two earlier posts.

Another option is to modify the RNC to give it balanced I/O. There are transformer solutions to this challenge if you like the color they impart.