SD Mix Pre line out question

omnikron

omnikron

Well-known member
So I'm looking into a quality recorder for my mix Pre. I'm currently using a DR-03 which is great but I'd rather use the XLR line outputs on my Mix Pre than the tape out. It just seems more solid than a flimsy 1/8" cable that could easily get unplugged.

I'm having a hard time wrapping my mind around the different line output levels... there's +4db and -10db... does the Mix Pre output either one or both of those levels?

The recorder I'm looking at is a Fostex FR-2LE but it looks like the XLR inputs are ONLY for MIC level. The TRS inputs on the Fostex are rated at -10db. So I guess my question is this. Would it be possible to go out from the XLR line outs on the Mix Pre and IN to the TRS plugs on the Fostex?

I really would just like to be able to wrap my mind around the concepts of this line level thing.... what is this +4 and -10 thing anyway? Thanks for any help!
 
-10dB is the nominal level for "consumer" line-level signals. Unbalanced (meaning two-conductor: + signal, and shared -/ground), via RCA or 1/4" or 1/8".

+4dB is the nominal level for "professional" line-level signals. Balanced (meaning three-conductor: +, -, ground) via XLR or 1/4" TRS. You'll hardly ever (if ever) see balanced via 1/8" TRS.

These are values for the actual strength (power) of the electrical signal flowing through the cables, and have nothing to do with the signal level as the meters would display.

The MixPre puts out line-level on both the XLR and 1/8" outs. The XLR outs are +4dB, and the 1/8" Tape Out is -10dB. Using the Tape Out to dual 1/4" TS in on the FR2-LE is actually a pretty good setup. You can take the XLR line outs of the MixPre and send them to the 1/4" ins on the Fostex using a conversion cable that takes the XLR balanced out to 1/4" unbalanced.
 
Awesome, thanks Alex! So really, just going from balanced XLR to unbalanced 1/4" TS would change my signal from +4db to -10db so it would be acceptable for the FR2-LE? Or would I also need some kind of pad or attenuator? I'm trying to understand if this conversion cable is simply an XLR to 1/4" unbalanced or if there's some specialty part on it?

Are you basically saying that in the end, I should be getting the same quality either way and it's really just a matter of the which connector I prefer to use?
 
"just going from balanced XLR to unbalanced 1/4" TS would change my signal from +4db to -10db so it would be acceptable for the FR2-LE?"
-- It would still be +4dB.. but unbalanced. I don't know about the Mix Pre, but other SD mixer's line out are actually referenced to 0dBu.
If you have a FR2-LE, do you really need the Mix pre? Better pre amps for sure, but the FR2-LE sounds pretty good without the SD as a front-end.
 
There are cables that have in-line conversion and impedance matching.

As for the need... I use a MixPre-D with an FR2-LE as a compact, run-and-gun kit. Yeah, the FR2-LE has pretty good pre-amps, but the side meters that are visible from the bag are pretty lousy. Also, level control isn't as practical on the FR2-LE.

So along with an increase in quality of the pre-amps, the MixPre brings better control and metering as well as the "unclippable" limiters.
 
Rick: I've wondered the same thing but I think Alex nailed it on the head... and since I already have a Mix Pre, I'm looking at this more from a strictly 'recorder' point of view.
Alex: So the big question for me is how to get the highest quality recording out of the Mix Pre. If I take the +4db XLR outs on the Mix Pre and convert them to unbalanced TRS so they can go into the -10db inputs on the Fostex, am I going to be having issues with peaking since the signal is much hotter coming out the Mix Pre than the Fostex is rated for?

And then what's Rick talking about when he says most SD devices output 0db line out?? Sheesh, how many standards are there for line out and what are the ramifications? i.e... is there some level of tolerance for most recorders when the line in/out levels don't exactly match up?
 
1/8" Tape Out to dual 1/4" TS inputs. Plain and simple. The 3' cable (or shorter) that you'll use will have no adverse effects on the signal.
 
I do something very similar going to a PMD-671. It's line in is RCA, so MixPre tape out to RCA.

You can get cables with a right angle 1/8" plug and it's in a bag so there really hasn't been any problem with fragility.
Works great.
 
Oh, and there are a ton of standards. There are also RS-xxx like the old RS-232 serial cables. RS stands for Recommended Standard. A standard that people couldn't agree on...
dBu refers to the reference level. If you have a few years you can study it all but your only going to deal with a small handful 99% of the time.

Wait till you start to deal with video codecs, now that is a nightmare.
 
noob mixpre question, but does it act like a preamp? I'd assume so seeing that it takes a mic in signal and outputs line level, but i wanted to double check
 
JAWflyer3 said:
noob mixpre question, but does it act like a preamp? I'd assume so seeing that it takes a mic in signal and outputs line level, but i wanted to double check
Click to expand...

That would be the "Pre" in "MixPre".

It doesn't act like a pre-amp. It is a pre-amp. Or, rather, a pair of pre-amps.
 
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