Preamp with ADAT-Out - "isolated split"?

[Christof]

If I'd use a passive splitter and feed the inputs in an Preamp with ADAT-Outs (M-Audio Octane for example) - would this work as an isolated split?

[Remoteness]

Well, if your passive splitter has transformers and you take those feeds it would be isolated. Also, the ADAT lightpipe output is isolated since passes signal via light and not copper.

[Don S]

Instead of the octane, why not use a Mackie Onyx800 and use the analog outs as an active split? I do it all the time. It's a handy little box!

[Drezen81]

I guess this doesn't speak well for my experience, but what is an isolated split and in what situation do you apply this technique?

I own the m-audio octane with the adat-lightpipe so i guess this could apply to me.

Does the sound change when I use the adat output vs. using the analogue outputs on my M-audio octane?
the preamp being used is still the one (or eight) on the Octane unit. Its just converted a/d sooner in the chain, right?

This is my my first post on this site. I learn alot and get much of my motivation from reading these threads about recording. Thanks.

[cioto]

Originally Posted by Don S

Instead of the octane, why not use a Mackie Onyx800 and use the analog outs as an active split? I do it all the time. It's a handy little box!

Or even the new, pretty, cool, Presonus Digimax FS ??

[Gerax]

I guess that would be an isolated split, and I do it all the time with my pres to feed my primary and backup recorders (ADAT outs to HD recorders and analog to DA78 tape backups). My only concern with this setup is that if you use the analog split to feed a FOH board (or monitor) you are forcing the engineer to accept line levels from your preamps, and your gain staging, which could be right for your recording purposes, but it may be not for FOH or monitor duties...not all FOH engineers are willing to take line level signals that they cannot turn down in level...and if the quality of the pres you're using is lesser than that of the console pres they may argue on that. I think it takes a fair amount of planning and testing with the FOH guy to avoid unpleasant surprises. As a side note unless you have a parallel ADAT out (such as those suitable for S/MUX that act as dubles at 44.1/48 KHz) or other digital out you cannot run a backup recorder in parallel with your primary...

For Don S: how do you like those Mackie Onyx pres? It's been a while since I've been thinking about getting one for my 24 track setup, it would be really handy with all of those I/Os, but I'm a bit afraid that with all of those bells and whistles for the price the quality of the preamp could be suffering...

Hope this helps

L.G.

[Don S]

Originally Posted by Gerax

For Don S: how do you like those Mackie Onyx pres? It's been a while since I've been thinking about getting one for my 24 track setup, it would be really handy with all of those I/Os, but I'm a bit afraid that with all of those bells and whistles for the price the quality of the preamp could be suffering...

Hope this helps

L.G.

If you're giving the FOH Balanced line level, then there shouldn't be any problem. You'll know instantly that a pre overloads (or clips). I usually have the oposite problem with FOH guys. They like to run signals vey hot through the board.I've occasionally attempted to take the direct out of a channel to find it clipping and distorting without the FOH guy knowing or caring. In that case, an iso split is your best friend.

I like the Mackie pres. They'll never knock your socks off like a first rate pre, but I've never gotten anything that was not pleasant sounding and usuable. I use them for less sonicly important tracks in live situations. I.E. boundary/ambient mics, hat, toms, accent mics like harp (in orchestra), winds, ect.

3d audio made this CD that auditions about 30 preamps with the same mic and performer. The prices range from $50 to $6000 per channel. After a blind listen, I thought half were better than Mackie, half were worse.

[Christof]

Thanks for all your suggestions so far.

As I'm just trying tostart doing some live recordings without any "big investment" I'd try a split without x-formers. I won't work with any big names - just local bands probably. I'd even try to work with a laptop instead of a dedicated recorder (with RME Digiface as interface - providing 3x ADAT In/Out + L/R analog for Phones). And there won't be any backup either!
So this is going to be low cost.

I got some x-formers, but I think they are not specified to be used in this area - if anyone could comment, that would be great help. The data can be found here:http://www.da7.com/filearchive/Chris/rk-482-2.jpg
Some of the german terms explained:
1. Application: input transformer
3. Source
4. Termination
If they could be used for splitting mic-lines, the idea would be to let one signal just passing through (so phantom could be applied) and two signals isolated through the x-formers. IF...

Without transformers I thought about two possible scenarios:
A) Splitting (without X-former) - one way to the FOH, the other to my preamp. ADAT-Out used for recording.
This way FOH / Recording could both adjust the levels as they want to - but you should probably be thinking about phantom power...

B) Going direct into the preamp, using the Line-Output for the FOH and the ADAT-Out for Recording - as Don S suggested.

As the ADAT is using a lightpipe cable there is a perfect isolation between the preamp and the recorder.
If the Recording-preamp is using the same plug as the FOH, there should (!) be no ground-loop. BUT IF there is any problem in the FOH - the signal of the recording-pres could also be affected...?

Any comments welcome...