higher-end pres into line-ins on interface

Chris Tondreau

Chris Tondreau

Member
I have three very good mic pres - the Daking Mic Pre One, Universal Audio 710, and the SSL Alpha Channel.

I have my main interface, the Steinberg MR816, and have also connected to it the Behringer ADA8000, which I use whenever I need more than the 8 inputs I get from the Steinberg. The pres in the MR816 are very decent, but do pale by comparison to the other more expensive ones.

The SSL is a new purchase. Until now, I have been going from the UA710 and the Daking MP1 line outs to the line-in (center of the combo jacks) on the MR816 and keeping the gain on the MR816 very low.

The SSL Alpha Channel has SPDIF, so it can connect directly to the SPDIF in on the MR816. The only problem is that direct monitoring is not available on the MR816 SPDIF inputs, so the first solution that comes to mind is to go from the line out on the SSL into a third line in on the MR816.

This would give me 3 very good inputs, 5 very decent inputs, and 8 usable inputs. (IMHO, the pres on the Behringer, I would describe as "very usable.")

With these good preamps, am I wasting three inputs on the MR816?

Would I be better to have 8 decent inputs on the MR816 supported by the three very good preamps going into the first 3 channels on the Behringer at line level (Behringer trim pots down as much as possible so it is basically straight in and straight out through the converters with as little interaction with the Behringer pres as possible)?

Would that give me 3 very good inputs, 8 very decent inputs and 5 usable inputs?

Or is there a better option that I have not considered?

Thanks!
Chris
 
How many inputs do you need at one time? Are you recording a complete band or individual tracks?

To me, it comes down to a matter of quality of the converters in the interfaces: Steinberg v. Behringer. Not sure how much of a difference there will be. It's quite possible the converters are exactly the same. You can probably us the Line Ins on the ADA8000 with your external mic pres and not notice a difference.
 
I'm usually just recording individual musicians.

However, there are times when I DO track a whole band and want/need more than the 8 analog inputs to the MR816. That was actually the purpose, originally, behind getting the Behringer ADA8000 in the first place. So, I'd do, say, kick, snare, overhead L, overhead R, floor tom, hi tom, mid tom and bass through the Steinberg, and a scratch vocal, scratch guitar and maybe a scratch keyboard, or extra tom or whatever though the Behringer.

The converters in both the Steinberg and Behringer units are both excellent, as indicated by both professional reviews and various head-to-heads I have found on line against other much more expensive units - Apogee, Prism, etc.

The problem is that, as far as I know, neither unit has the line-ins going straight to the converters. They both go through the preamp stage. The preamps in the Behringer are very usable. The preamps in the Steinberg are measurably better.

But if I'm running a line level signal from one of the more expensive mic pres into either unit, with the gain pot as close to right off as possible, does the quality of the preamp even come into play?

Chris
 
Chris Tondreau said:
But if I'm running a line level signal from one of the more expensive mic pres into either unit, with the gain pot as close to right off as possible, does the quality of the preamp even come into play?

Chris
Click to expand...

From what I can see through a quick search, it's like you said, both units have xlr and 1/4 routed through the same circuitry. I don't have any experience with either units, but yes, the preamps come into play. How much, I don't know. I'm guessing it's a matter of noise floor and what is acceptable to you. Kind of sucks they are like that, but they are pretty much consumer-level interfaces and full of compromises.
 
I would wager that it will make very little difference in real terms.

Feeding a 'nice' preamp into a 'not-so-nice' input stage with no gain applied will affect the signal very slightly, but unless someone with seriously trained ears, years of experience and access to the exact same signal passed through a different preamp/input stage does an A/B test, noone but you will ever know it happened.
 
Thanks for weighing in. I guess I was hoping that someone would have a definitive answer. :-)

I think what I'll do is actually do a test myself. Because the SSL has SPDIF out, I'm thinking something along the lines of:

1. Connect SPDIF out of SSL to SPDIF in on MR816. This does, indeed, bypass the pres in the MR816.

(the reason I don't just do it this way anyways is because direct monitoring does not work on the SPDIF ins on the MR816 - only on the analog inputs.)

2. Connect analog line out from SSL to line in on Behringer.

3. Connect insert line out from SSL to line in on MR816.

4. Record a vocal, bass, guitar - capturing one performance of each via the three different input routings. Thus, the ONLY variable will be the interaction of a preamp (with as little gain as possible, if any) vs the total absence of the interaction of a preamp.

5. Test #1 - straight A/B/C listening. Are the differences perceptible or describable?

6. Test #2 - Use phase cancellation - A-B; A-C; B-C. What are the *actual* differences between the tracks?

Any recommendations on how to better test this?

I'll report back, probably by the end of the weekend.

Chris
 
Just read this.

Wouldn't using the Insert point on the SSL stop the signal getting to the line output unless you feed it a signal on the return line of the insert cable? Inserts are generally in series rather than in parallel with the input so you normally need to have a returning signal rather than using it as an output.
 
Chris Tondreau said:
Would I be better to have 8 decent inputs on the MR816 supported by the three very good preamps going into the first 3 channels on the Behringer at line level (Behringer trim pots down as much as possible so it is basically straight in and straight out through the converters with as little interaction with the Behringer pres as possible)?
Click to expand...

Not unless you need more than 8 tracks. There is something that is missing from this thread: A discussion about jitter. When you hook up your ADA8000 to your MR816 one of those two units is the master clock. Whichever one you choose has the better sound. The "slave" unit will have jitter (sound quality reduction). I have experienced this myself with a Digi002 and Audient ASP008.

https://www.soundonsound.com/sos/jun10/articles/masterclocks.htm

For times when you require 2 tracks or fewer, your optimal set up is probably to bypass the pres on your MR816 and use your high quality preamps just using AD conversion on the MR816. Use the line inserts 1 and 2 and your 2 favorite external preamps.
 
The MR824 has a wordclock out that should eliminate any issues with jitter if the devices dont sync properly via adat or spdif, which is pretty unlikely.

With most modern interfaces there isn't really a big issue as they nearly all include some 'jitter reduction technology'.

Whichever one you choose has the better sound.
Click to expand...

Not true, and the article you posted says the exact opposite as well:
"Overall, it should be clear from these tests that employing an external master clock cannot and will not improve the sound quality of a digital audio system. It might change it, and subjectively that change might be preferred, but it won't change things for the better in any technical sense. A‑D conversion performance will not improve: the best that can be hoped for is that the A‑D conversion won't become significantly degraded. In most cases, the technical performance will actually become worse, albeit only marginally so."
 
The MR824 has a wordclock out that should eliminate any issues with jitter if the devices dont sync properly via adat or spdif, which is pretty unlikely
Click to expand...

That is simply not the case dude. The wordclock out may help them sync and avoid major clocking issues (crackles and pops). It will absolutely not eliminate all jitter.

Maybe I wasn't clear: The unit that is using an external clock source will have reduced quality.

That article also is for high end equipment. Either in that article or another one they indicate that with cheaper gear the problem of jitter is only more pronounced when using an external clocking source.
 
That's perhaps more like what you were trying to get across the first time round, but it was misleading/incorrect the way you wrote it - apologies if I seemed to jump on you there :/

I'd be interested to see if there is a noticable problem with jitter, the options seem to be feeding the signal through another input stage (I haven't seen anything to suggest that the line input on the mr816 bypasses the preamp) or tolerating a small amount of jitter on adat/spdif. I'd probably say it's not a significant issue.

My money is on both of them being a better option than feeding the pre's through the behringer unit.
I just got round to looking up the specs, i can't say that I would recommend feeding a high end pre through something with a dynamic range of 103dB. The numbers don't tell the full story, of course, but sometimes they give a good indicator.
 
Okay, sorry for the delay, but I finally got around to giving this a try.

Here are three files - each a stereo wav (9MB) = 52 seconds in length. I exported to stereo because the files would play better in some things.

Shared Google Drive Folder

Anyways... the first 20-ish seconds is a bass guitar plugged directly in, the next 15 seconds an electric guitar plugged directly in, and the next 15 seconds is a handful of metal things (a drum key, some coins, etc.) underneath a Studio projects C4 with a cardiod capsule.

The samples were all recorded with the SSL. The three tracks are:
SPDIF - SSL connected to MR816 via SPDIF directly in.
MR816 - SSL connected audio out to line in on MR816. (no, this does not bypass the preamp)
ADA8000 - SSL connected insert out to line in on Behringer. (no this does not bypass the preamp)

The file segments are only adjusted for volume so that each segment produces the exact same maximum peak output.

I could not do phase cancellation as the audio samples were not actually identical. They came in at slightly different levels, so they were slightly different recordings.

So, all we are left with is the subjective A/B/C listening test.

To my untrained ear, there is practically no difference. Sometimes, I can tell that something has changed, but it is hard to say what or how. Just that something is somehow indescribably and barely perceptibly different. Most of the time.... I can't hear any difference at all.

Visually, the parts of the files where the guitar is and where the metal objects are, you can see that the direct to SPDIF and the line-in into the MR816 are much more accurate and faster with the transients than the Behringer.

But for all practical purposes, I'm not sure it is worth it to sweat over how to best connect it.

Chris
 
Great stuff, I'll have a listen later when I'm back in the studio.

From your initial impressions would you say that it's possibly more important to worry about what you connect rather than how in this case?
 
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