Digi 003 Rack Analog Outputs (Impedance?)

[lowlights]

I'm running Analog 7-8 OUT on my Digi 003 Rack out via balanced cables to a "tube" mic-pre I don't use anymore, just to get a little tube warmth/saturation into my in the box track mixing.

It's a fairly new effort, but I'm liking the extra "fatness" - I port back to Analog 7-8 IN and have a buss called "Out2Tube". Each session gets a stereo Aux Input track with an input of Analog 7-8 IN and send that to Output A1-2 and mix it all in in different quantities from each track.

I'm using an ART TPS-II mic pre - which has adjustable input impedance - which I can dial from 150 to 3000.

The question is - um - what is the impedance of the Digi's analog outputs?

I tried the 003 manual but can't find a figure (if there is one).

I apologize if this is now the dumbest question on DUC.

[TOM@METRO]

Before Impedance becomes an issue, you do realize that you are subjecting your mixes to another DA then AD conversion with less than great converters into and out of a less than great preamp, right? What you are losing is likely far more than the gain.

[albee1952]

I'll hit this from another angle. Your path may have latency due to conversion delay(all converters take a few dozen to a few hundred milliseconds). If I were digging the sound of the tubes(sounds like you are) I would record the signal to a stereo AUDIO track and then nudge it to align with the rest of your audio. If you use a click count-in(sent to the tubes, and recorded to a new track) you can use Tab to Transient to determine exactly how much offset you have so you can adjust for perfect alignment.

As to the impedance question, the answer is; try them all and use the one that sounds the best. I know this is not the technical and simple answer you hoped for, but it is the real answer. All the technical jargon will be out the window if the "correct" setting doesn't sound as good as an "incorrect" setting. The technically correct approach would be to use a setting the is roughly 10x the output impedance of the 003(but my hearing trumps specs in this situation)

[lowlights]

Tom - I did consider the out/in conversion for this "effect send" and the extreme cheapness of the ART (unfortunately the ART doesn't have an S/PDIF or I'd use that for my out). It was more of an experiment in creating a hardware send, but I thought - well, it's the only tube device I have handy, let's see throw it into the signal chain and see what happens, as it's doing exactly $150 of nothing right now.

I find just a touch of this effect send does the trick - I use a send of about (-30) to (-25) on different tracks (sounds great on acoustic guitar, but gets kinda brash on vocals in a hurry), but it definitely gives me a fuller/warmer that I like; I'm not sure if it's the tube in the chain or the microsecond of delay the send gives me, but I've tried short plugin delays 30ms and shorter instead, and they don't give the same feel as this send does.

I've definitely been putting ears on it - but I was just afraid I was bringing more noise back than I needed by having an incorrect impedance set on the ART input (there's definitely slight noise at any impedance higher than the minimal 150).

[lowlights]

P.S.: How many posts do I need before I can be Hobolights?

[albee1952]

Originally Posted by lowlights

P.S.: How many posts do I need before I can be Hobolights?

I think your count needs a comma in it But I like the way you think

[vortex4001]

Originally Posted by TOM@METRO

Before Impedance becomes an issue, you do realize that you are subjecting your mixes to another DA then AD conversion with less than great converters into and out of a less than great preamp, right? What you are losing is likely far more than the gain.

Totally not true, Pre-amps have no A/D converters nor D/A converters, the only thing he might lose is the original time stamp that he'll have to just compensate by moving his tracks back at certain milliseconds.

[browniespeaks]

@Vortex the extra DA and AD is going out of the 003 and back into the 003. Hes using the outboard tube gear as an insert effect loop. For the latency depending on version of ProTools this should be the least of his problems as there are multiple places to set hardware insert latency so that ADC can help him out with the nudging.

I have no idea of the actual answer to the OP's question of impedance, im assuming your trying to match the tubes? your probably way over driving the tube as i'm afraid even at low levels most of the consumer and prosumer tube pre's will introduce ALLOT of noise before they actually respond in any coherent way. Whats your noise floor with this method? (if you put no sound threw the tube but its on what are the levels at the return?

What your ears may really be perking to is the EQ curve that tube is throwing on your audio. check this out http://www.foxaudioresearch.ca/changetubes.htm

[lowlights]

As the original poster, I appreciate all these responses - but to be honest, the thread has gone moot.

I no longer use a Dig003 (Mbox Pro 3rd Gen now), and am now longer using the ART as a hardware send. My main interest was merely in properly picking the right line volumes (+4 or -10) so that I aligned my "outboard gear" with the Digi003. I realize some latency and conversion issues took place in the back and forth - but I was cool with that. I'm a home studio guy and just wanted to try it out.

I find I get much of the same thickening (just a touch) with a Softube and Massey plugin that I was getting with this previous in-and-out solution. It was just a fun experiment to try getting "outside the box" re: mixing in PT.

[TOM@METRO]

Originally Posted by browniespeaks

@Vortex the extra DA and AD is going out of the 003 and back into the 003. Hes using the outboard tube gear as an insert effect loop.

^^^ what he said ^^^

Originally Posted by vortex4001

Totally not true, Pre-amps have no A/D converters nor D/A converters, the only thing he might lose is the original time stamp that he'll have to just compensate by moving his tracks back at certain milliseconds.

It's not about A/D conversion in the pre-amps themselves, but rather the conversion time involved in the converter chain in and out of the interface itself.