Nagra LB/Sound Devices 702 analog outputs: where in the chain?

[Mikycoud]

Hi,
First and foremost, because this is my first post, let me say hi to all members here.
Now on to my question:
Does anyone know where in the chain the analog outputs of these devices are? (when the input is analog)
To elaborate, does the output happen post preamp, pre AD (analog input--->preamp--->output)?
Or does it happen post everything (analog input--->preamp--->AD--->DA--->analog outputs)?
I have to assume the headphone output is post AD, but what about the balanced ones?
The idea is to route a balanced feed to a camera in the cleanest possible way. If those devices send the signal post AD DA, then it's likely that this will add some noise.
I couldn't find any info or block diagram on the Nagra LB, and the Sound devices routing options are so vast that I kind of got lost and couldn't figure out whether what I'm trying to accomplish is feasable.
Thanx for any input!

[Petrus]

I can not answer your question, but as the S/N ratios of those units are around 115 dB even via AD/DA I think your question is pointless. At least with 16 bit audio cameras (and even with 24 bit systems, belive me).

[Mikycoud]

Hi, and thanx for your reply.
S/N above 115db on the analog outputs? Are you sure? May I ask where you got that info? I have the Nagra LB manual here, and can't find any info on that.
I hope you're right though.

[Mikycoud]

Can anyone with experience with either of those devices give me some info on the quality of the analog output?
After searching a lot, the only opinion I could find on the Web seems to confirm that, on the SD702, the analog outputs are post AD DA, and that the quality isn't top notch. Funny thing is it was an old topic on Gearslutz!
here's a copy and paste:
(taken from this thread: Questions about Sound Devices 702)
'Ghellquist wrote:
'Menu setting allows you to route the input signals through preamps and then out on the output XLR-s and the mini-tele line out. The signal is then AD-converted and DA-converted though, so while still giving great quality a standard preamp could be better. The headphone output could be used at the same time, it has a lot of drive but has slightly more hiss.'

What about the Nagra LB? Any opinion?

[tsvisser]

Nagra LB is also post A/D D/A.

[ghellquist]

I wrote that comment.
And it is true as written. The analog outputs are after AD and DA.

But to put things into perspective. The analog output are very, very good. The headphone output is very good as well. In both cases my experience is that the hiss of the camera input circuits totally swamps the hiss produced by the 722.

But if you want to go the full mile ( or marathon, whatever ) it is even better if you can avoid going AD and then DA and use a dedicated mic preamp instead. Of course. Your choice.


// Gunnar

[MichaelPatrick]

Routing in the Sound Devices 7xx series recorders is flexible because it is internally all digital. SD recommends digital output for critical quality feeds. In my experience (744T & 788T) the DAs are excellent, but who wants any conversion if you don't need it?

P.S. In this thread Ozpeter included a link for input noise specs on a number of field recorders, including SD722.
FR2LE VS. Sound devices 722, sounds the same to me

[Mikycoud]

thanx for all the inputs.
So, in a nutshell, for about £2000, does it seem like a good idea to you to buy the 702 and use it as:
1) a basic mixer connected to a Panasonic HMC150 via post AD DA analog output.b (A 552 would be better suited for that, but our budget doesn't allow for that.)
2) Basic SFX recording and ambient sound (nothing fancy, most of the time mono, with the occasional M/S). Mics are Senn K6/66.

Or would it be better, for my applications, to get a soon-to-be-replaced 302 and combine it with a Marantz PMD661.

The general consensus seems to be that the preamps in the 702 are better than the ones in the 302.

What would you do, and why?

Thanx!

[tsvisser]

If your just looking for a portable battery operated preamp, maybe a Grace Lunatec V2 or V3 would work for you? There was also the Apogee Mini-MP, which was a big step up from the built in pres on the Mini-Me, its sister unit. Sound Devices even makes a couple single channel preamps.

On the recorder front, I would just bite the bullet and get a 702 or better yet, 702T.

I know someone who was selling a couple of Mini-MP units, if you are interested in those.

[Mikycoud]

Hi,
One of the reasons I'me leaning towards the 702 is that I think I could also use it as a basic mixer. I know it wasn't designed for that, but my needs are pretty simple. I'll probably bite the bullet and order it today. Doesn't anyone on these fora use a 702 this way?