Preamp > DI > DAW (levels)

N

nickson

New member
Hello.
I've never really thought of the importance of the right level of recording. The only thing I knew: nothing should be clipping.
But when I started using tube preamp (just a simple and cheap one) before my DI, the things got a bit confusing.
For example, when I record acoustic guitar using a condenser mic through preamp, I can see the big difference between the signal level on my preamp and the level in my DAW when the track is begin recorded. The first one is always higher. The same thing with bass/electric guitars connected to DI through a preamp.

So my question is: what is the rule I can follow to set the right level on a preamp to make it right when it reaches the DAW?
 
Hi,
Can you describe your chain in detail, please?
Is the DI a DI box or the instrument level input on an interface? (models and names, please).

The reason I ask, DI usually implies instrument level input and it sounds like you're running a preamp before that.
A preamp generally puts out line level signal so you'll have a mismatch going on.

Tell us more. :)
 
First off I would ask what actual gear you are using?

Why would you use a tube preamp before a DI? Or did you mean AI?

The gear you are using is as much as important as the way you are using it. Not all gear has the same input/output levels or appropriate setup.

---------- Update ----------

Super Steen is on it!!! :D
 
I use Tube Ultragain Mic200 and Line6 Toneport DI-Gold.
I use preamp before DI because it doesn't have built-in support for phantom power for my condenser mic. And in case of guitars - I just use preamp to get more warm tones.
 
The Line 6 is being used as the USB A/D interface.

Others may disagree, but I first think your chain has a lot to be desired. The line 6 is intended to be a true USB DI. Plug in instrument, record. The pre-amp, is a true pre-amp. The problem I see is going from the pre-amp to the DI box. Obviously it works, but sure does seem like it is not a very good chain.

Wouldn't the Line 6 give you what you are looking for without the pre-amp? I am not sure how well the Line 6 would do on vocals. Best you can do is Pad the input on the Line 6 when coming out of the pre-amp to get the level correct as it is expecting a guitar level input. It could be your signal from the pre-amp is just too hot. You may have to reduce the output signal from the pre-amp as well.

Get a good clean signal to your computer and then get the levels up at mix.
 
The Tone Port DI has a USB out but it's the wrong tool for the job. It's designed to feed instrument level sources (i.e. a guitar) into your DAW, not microphones or line level stuff.

"Line Level" is the level that typically used in any electrically powered gear--mixers, that sort of thing. Microphone level tends to be around 50dB lower than line level and instrument level is somewhere in the middle...say about -25dB compared to line level.

By running your mic through a pre amp you're raising it to line level which is hotter than you'd normally put into the Tone Port--then you're turning it down to what the DI box is designed to use. It sounds like you're getting away with it but it's not the best way to work.

Anyhow, there are no hard and fast rules for gain staging but a basic guideline is that you want you levels to be fairly consistent through the various stages of a system. Pretending that you were feeding from your mic pre amp into a proper audio interface, you'd want to set your gains at each stage so none are "undoing" the work of a previous step. You don't want the mic pre turned up really loud then turn it down at the interface...but you don't want the mic pre really quiet and turn it up at the interface. You want both at similar levels, hopefully in the "sweet spot" of the gain structure.

In your case, you're NOT going to get this sort of structure because the mic pre is designed to put out a higher level than the DI is meant to receive. As I said, you can obviously get away with it, but...

...start saving for an audio interface!
 
So you say Line6 TonePort IS NOT an audio interface? A bit surprising to me. I thought every interface has the same principle of work. Can you post any audio interface that is meant to be working with preamps? (just for example).
 
The Line6 is an audio interface in certain respects but it's not designed to piggy back another preamp. For that, you would want something with a "line in" option so the preamp signal goes straight through to the computer, bypassing any other preamps. Preamp into preamp is not a good option. It can be done, with correct gain staging but not ideal.

Another option would be a dedicated PCI soundcard so you could both the Line6 and the Tube Pre both connected. (Like mine for example, M-Audio 2496 with 2 Preamps going into it.)
 
nickson said:
So you say Line6 TonePort IS NOT an audio interface? A bit surprising to me. I thought every interface has the same principle of work. Can you post any audio interface that is meant to be working with preamps? (just for example).
Click to expand...

Hi Nickson,
"Will X work with Y" is sort of blindly pointing and seeing what happens.
If you learn the basics of the signals you're dealing with and the path, you'll be much better equipped in the long run. :)

There's more to it than this but you're dealing with three main levels of signal.
Microphone level - lowest level
Instrument level (DI)- mid level - comes from bass guitars, electric guitars, usually not keyboards etc
Line level - hottest of the three - Keyboards, synths, mixers, preamplifiers, these all usually put out a line level signal.

If you plug line or instrument into a preamp, you'll overload the path.
If you plug a microphone into a line input, you won't hear anything as the incoming signal is too quiet.


Small interfaces usually, or often, have all these things build in, but you need to know which is which and when to use them.

Mic goes to mic preamp - almost always XLR input. Easy.
Guitar/bass goes to DI or instrument input - usually unbalanced jack (TS)
Keyboards, synths, preamplifiers go to line input - Usually balanced jack (TRS)

DI boxes are for the people who don't have an instrument input.
They take the signal from guitar/bass and alter it to put out a microphone level signal.
This means you can use a DI box with a microphone input, see?

Hope that's useful.
 
Yeah, that's very useful! Thanx)

One more question (just to make sure I got it correctly).
Some audio interfaces have "HI-Z" switch. Does this work like DI when switched on and like "line in" (for hot signal) when switched off?
 
nickson said:
Yeah, that's very useful! Thanx)

One more question (just to make sure I got it correctly).
Some audio interfaces have "HI-Z" switch. Does this work like DI when switched on and like "line in" (for hot signal) when switched off?
Click to expand...

Yes, usually when you see a jack with a hi-z switch it means high impedance instrument input.

Up above when I said "There's more to it than this...but", I was leaving out the differences in impedance between all the inputs.

Hi-z/High impedance/DI/instrument usually mean the same thing on an interface jack input. :)
 
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