Teach me how to DI with amplitube or anything else!

[Delirium trigger]

I am new to DI but I am in a situation where I need to do it. Let me see if I have it right, I can record the guitar tracks as usual with the amplitube plug in, once I take the plug in off, the dry track will be there. Now, I run that track to output 3 on my saffire pro 40, into the amp, and record it on Input 1 correct? Are there any other steps I would need to take?

[t_e_l_e]

yep, you need a reamp box between the saffire output and your amp otherwise the impedance and sound level will be off and your amp will sound weird in the best case...

a reamp box is something like a reverse DI...

something like this:

http://www.radialeng.com/prormp.php

 

 

or do you mean reamping without a real amp but directly with amplitube again?

but this, why would you want to do that?

you just need to copy the track in your DAW and change the plugin settings for a different sound

[Delirium trigger]

yep, you need a reamp box between the saffire output and your amp otherwise the impedance and sound level will be off and your amp will sound weird in the best case...

a reamp box is something like a reverse DI...

something like this:

http://www.radialeng.com/prormp.php

 

 

or do you mean reamping without a real amp but directly with amplitube again?

but this, why would you want to do that?

you just need to copy the track in your DAW and change the plugin settings for a different sound

 

Explain this again, I've read online and seen youtube videos where people are using the Saffire pro 40 to reamp instead of buying a DI box due to the way the saffire mixer works. Something a lot of interfaces don't do. And I mean recording an EP with amplitude, but then later on putting the tracks through real amps.

[t_e_l_e]

the outputs on the saffire pro 40 are line level outputs (we have one ourselfs). you can connect this to an guitar amp. be sure the levels are initially set low to avoid ear bleeding.

 

the problem is, it does not behave as a guitar output, e.g. a pickup, does not have the same impedance and different levels. the levels you can adjust with volume knobs to a certain degree until you add too much noise. but for the impedance mismatch there is no shortcut, the amp, especially a tube amp, will behave different, when it sees the wrong/unusual impedance in its input.

 

it will not sound the same as when you plug your guitar direct to the amp and play it again

with a reamp box you can avoid this behaviour

 

but try it without a reap box, record the results an see if you like them....

[WRGKMC]

You don't need DI/Reamp box. It does make it easier but you can do the same thing matching impedance for $5.

 

You just need an attenuator between the Interface and amp to match the line level output to instrument level. Either a 3db http://www.parts-express.com/rca-line-level-audio-attenuator-3-db--266-232 or 6db should do fine. http://www.parts-express.com/harrison-labs-6-db-rca-line-level-audio-attenuator-pair--266-242 they have 12's too but that's likely overkill. I'd just buy two of the 3db and you could run two to get 6 if needed. These are RCA connectors you may need 1/4" adaptors as well.

 

They also make XLR attenuators of all kinds which include transformer type step up and down. These may be better for matching to mic inputs and do provide better fidelity, but you wont need it with a guitar.

 

 

A guitar ramp box has a fancy case and variable pot for levels, but once you get the right attenuator on there you can simply tweak between the amp volume and DAW track/mains volume and get the levels you need. I'd set the guitar amp for where you'd normally use it, then tweak the daw track/mains to get the same levels on the amp. If you're having to adjust the track down too low and the amps still too hot, you simply add another attenuator till both the amp and DAW sliders are running in a normal range.

[Delirium trigger]

I saw on youtube where a guy was running out of the safire pro 40 and into an OD pedal and claiming that resolved the issue. Does it?

[WRGKMC]

The gain for the pedal is going to be higher then a guitars output.

 

A typical line out connection has an output impedance from 100 to 600 Ω and produces up to: Nominal level +4 dBu, Nominal level, 1.228V Vrms Peak Amplitude, 1.736Vpk Peak-to-Peak Amplitude, 3.472Vpp

 

The impedance is much higher then line levels too between 2K~15K ohms. A guitar pickup signal will vary in signal strength from between 100 mV rms to over 1Vrms . Depending on the pedal used it may attenuate the line level down to instrument level. If its got a input attenuator it may work OK. In the cases I've tried this I've found the impedance mismatch darkens the tone and the guitar doesn't have the same edge it does with proper impedance. Its works but it works poorly.

 

 

[Delirium trigger]

Okay, hang on.. Let me understand.

 

Let's say I plug into input 1 on saffire pro 40, record a guitar track using amplitube as a plug in. REMOVE amplitube and then I have the DI track right? Or is that input not powerful enough?

 

Now, I run a TRS from output 3 on the saffire to the guitar amp's input. I am able to adjust the outgoing volume of this input via mix control. Then I tell the di track I recorded to output via output 3 in mono, instead of through the normal 1 and 2.

 

Then, I plug a mic into input 1 and mic the guitar cab. Make a new track which is recording input 1. I hit record, and it records it.

 

I'm not understanding why I need a reamp box? Why do I need one if the signal is going through? Is the signal not strong enough? Or is it too weak?

 

 

[t_e_l_e]

you can adjust the volume, to make the signal "strong" enough. but the impedance mismatch will mash up the frequency response of the signal.

 

in short it will change the sound of the signal, so the DI signal recorded will not be the same signal on your amps input

 

 

it might not be a big issue, but it can also sound dramatically different.

if you wired it as you said above, there is nothing you can damage here, so try it out and check your results

[onelife]

Okay, hang on.. Let me understand.

 

Let's say I plug into input 1 on saffire pro 40, record a guitar track using amplitube as a plug in. REMOVE amplitube and then I have the DI track right? Or is that input not powerful enough?

 

Now, I run a TRS from output 3 on the saffire to the guitar amp's input. I am able to adjust the outgoing volume of this input via mix control. Then I tell the di track I recorded to output via output 3 in mono, instead of through the normal 1 and 2.

 

Then, I plug a mic into input 1 and mic the guitar cab. Make a new track which is recording input 1. I hit record, and it records it.

 

I'm not understanding why I need a reamp box? Why do I need one if the signal is going through? Is the signal not strong enough? Or is it too weak?

 

 

 

As t_e_l_e suggests, try it and let your ears be the judge.

 

I would recommend using a regular guitar cable from the Saffire to the guitar amp's input instead of a TRS.. You'll have to keep the output level of the Saffire low enough that it does not overdrive the front end of your amp. A good way to set the level would be by plugging your guitar into the amp and recording something then plugging the output of the Saffire into the amp and adjusting the output level (of the Saffire) to match the sound of the guitar into the amp.

 

I also like the idea of using a pedal to match the levels - I do that myself in a variety of different situations.

 

 

[WRGKMC]

I agree with the others. Your are either ignoring or ignorant of the different impedances you're dealing with. You can turn the interface output levels down to drive the amp but some weird things happen in the process dealing with gain staging. Your noise floor is going to be much higher then it should and when you turn a line level down like that both the frequencies and dynamics shift out of their normal range.

 

Much of this will depend on the interface, guitar amp and how strong the original track was recorded. For example, If you have a guitar amp with a CD level input or effects return, that's a line level input to the power amp of the guitar amp and will work. If you've ever taken a cassette or CD player and plugged it straight into a guitar amp, you barely crack the knob on the amp and its too loud. The line level out of these devices are too hot for an instrument level input.

 

Again, a guitar pickup straight into an amp is very weak. The guitar amp has extra gain stages that boosts the pickup up to line level which drives the power amp. The output from your interface is already line level. If you plug straight into the guitar amp without properly attenuating the signal down first, you feed the amp too large a signal. Even if you turn the volume down, the amp is still seeing line level input and the noise floor will be higher then its supposed to be.

 

If you use a 6db attenuator like I mentioned, both the noise floor and the signal level will be reduced. You can then crank the amp gain up like you would with a guitar plugged in and all your controls for gain, and tone would produce their best tones.

 

Nearly all power amps are designed to be fed line level inputs. Its the job or the preamp to get the signal up (or down) to that level so it drives the power amp efficiently. In Pro PA or pro Hi Fi, you usually find the Power amp is separate from the Preamp. Powered PA cabs for example have the power amp built into the cabs themselves. In your more economic stuff like your typical Hi Fi unit, Powered PA heads or Guitar head, the preamp is built into the same chassis with the power amp for convenience. Its the job of preamp to bring the low level signals up in strength to drive the power amp correctly.

 

If you have line level already you cant feed it into a device that's designed to amplify weak signals without clipping, so you have to attenuate it down to one of the lower signal strengths the preamp is designed to accept. Some units like a stand alone mixer will have mic level and line level inputs. The XLR inputs feed to some additional preamp gain stages that boost a mic up. The output of the mixer is like level which feeds a power amp and the power amp feeds the speakers.

 

A Mixer may also have line level inputs. The signal can pass through the mixers EQ section and remain at line level without additional preamplification to feed the power amp. Some mixers have additional trim knobs to boost the line level signal. These are often used for guitar or other amp sources that are either too strong for mic level inputs or too weak for line level. Your interface has this kind of input that will allow you to boost your guitar up to line level.

 

Most guitar amps have only one signal level input which is instrument level so you can only feed them that signal level and get good results.

 

Here's some articles that explain the differences in signals. Memorize them. You will deal with these standards as long as you're involved in any kind of audio work. Be sure you make the link between signal strength outputs vs inputs.

 

http://www.ovnilab.com/articles/linelevel.shtml

 

http://en.wikipedia.org/wiki/Line_level

 

 

[Delirium trigger]

Okay, but let me ask this. Is the impedance corrected if I do it this way...

 

Record riff using amplitube plug in, plugged into input 1 on safari pro 40 with line instrument engaged.

 

Take the amplitube plug in off, then I have the Di track.

 

Run output 3 from the safari pro 40 to guitar in on Line 6 HD500

 

Run guitar cable from output of line 6 hd500 and set output to "front stack"

 

Will that give me the correct impedance? Basically using the HD500 as a reamp box? Not using any effects or amps, just running through it to get the right signal?

[Delirium trigger]

I agree with the others. Your are either ignoring or ignorant of the different impedances you're dealing with. You can turn the interface output levels down to drive the amp but some weird things happen in the process dealing with gain staging. Your noise floor is going to be much higher then it should and when you turn a line level down like that both the frequencies and dynamics shift out of their normal range.

 

Much of this will depend on the interface, guitar amp and how strong the original track was recorded. For example, If you have a guitar amp with a CD level input or effects return, that's a line level input to the power amp of the guitar amp and will work. If you've ever taken a cassette or CD player and plugged it straight into a guitar amp, you barely crack the knob on the amp and its too loud. The line level out of these devices are too hot for an instrument level input.

 

Again, a guitar pickup straight into an amp is very weak. The guitar amp has extra gain stages that boosts the pickup up to line level which drives the power amp. The output from your interface is already line level. If you plug straight into the guitar amp without properly attenuating the signal down first, you feed the amp too large a signal. Even if you turn the volume down, the amp is still seeing line level input and the noise floor will be higher then its supposed to be.

 

If you use a 6db attenuator like I mentioned, both the noise floor and the signal level will be reduced. You can then crank the amp gain up like you would with a guitar plugged in and all your controls for gain, and tone would produce their best tones.

 

Nearly all power amps are designed to be fed line level inputs. Its the job or the preamp to get the signal up (or down) to that level so it drives the power amp efficiently. In Pro PA or pro Hi Fi, you usually find the Power amp is separate from the Preamp. Powered PA cabs for example have the power amp built into the cabs themselves. In your more economic stuff like your typical Hi Fi unit, Powered PA heads or Guitar head, the preamp is built into the same chassis with the power amp for convenience. Its the job of preamp to bring the low level signals up in strength to drive the power amp correctly.

 

If you have line level already you cant feed it into a device that's designed to amplify weak signals without clipping, so you have to attenuate it down to one of the lower signal strengths the preamp is designed to accept. Some units like a stand alone mixer will have mic level and line level inputs. The XLR inputs feed to some additional preamp gain stages that boost a mic up. The output of the mixer is like level which feeds a power amp and the power amp feeds the speakers.

 

A Mixer may also have line level inputs. The signal can pass through the mixers EQ section and remain at line level without additional preamplification to feed the power amp. Some mixers have additional trim knobs to boost the line level signal. These are often used for guitar or other amp sources that are either too strong for mic level inputs or too weak for line level. Your interface has this kind of input that will allow you to boost your guitar up to line level.

 

Most guitar amps have only one signal level input which is instrument level so you can only feed them that signal level and get good results.

 

Here's some articles that explain the differences in signals. Memorize them. You will deal with these standards as long as you're involved in any kind of audio work. Be sure you make the link between signal strength outputs vs inputs.

 

http://www.ovnilab.com/articles/linelevel.shtml

 

http://en.wikipedia.org/wiki/Line_level

 

 

Well, I have line level inputs. I also have the ability to control the volume on all of the safari pro 40's outputs. For example, I can run output 8 out and control the volume of output 8. But how would I know how loud it needs to be? The safari comes with something called mix control which allows you to control the volume and reroute outputs with inputs. Here is a picture of it and you'll see what I mean. Those numbers in the blocks, whichever ones I put in blue (and any of them can go into blue) will be controlled by the volume knob.

 

[Delirium trigger]

BTW, I forgot to add, I also have multiple tube pre amps that I can run a guitar through too if that would fix the impedance better than HD500.

[onelife]

... I can run output 8 out and control the volume of output 8. But how would I know how loud it needs to be? the volume knob.

 

As I suggested in a previous post, plug your guitar into your amplifier and set the volume on your amp. Then plug output 8 of your interface into your amp and gradually bring up the volume of output 8 until your amplifier sounds as loud as it did with your guitar.