Questions about preamps and DI Boxes

[ahrenba]

Hey guys,

I have a couple questions about preamps. I have numbered the questions, so if possible, please number your responses. Thanks!!

1. Is an effects processor (such as the Line6 POD) considered a preamp? I realize that it "tone-shapes" the signal to match cabs from different eras, but is it technically a preamp (boosts signal)?

2. Look at this Product:
http://www.musiciansfriend.com/product/ART-Tube-MP-Studio-Mic-Preamp?sku=180581
It says: "High impedance instrument input bypasses the mic preamp circuitry for a shorter signal path. " Since this means that the instrument input bypasses the preamp, what is the use for plugging it in, in the first place?

3. In conjunction with the question above, do preamps ONLY boost signals from XLR inputs, or can they boost signals from 1/4" inputs also? The reason I ask is because the quote above makes it seem like the instrument signal should be bypassed. Maybe someone could explain this.

4. Do instrument outputs (such as from a guitar) need to be preampped?

5. DI Boxes.....Look here: http://www.musiciansfriend.com/product/ART-Tube-MP-Studio-V3-Mic-Preamp?sku=180610
"Also can serve as an exceptional direct box for impedance matching or simply improving the sound of any instrument plugged into it."
This is listed as a preamp...what makes it a DI Box, and what is the benefit of a DI box other than it converts a 1/4" input to an XLR output (balanced)? Does it change the tone like a preamp would? Was does it bypass the mic preamp? Is it still going to be preampped?

6. Is an active (powered) DI box considered a preamp? If so, why does the info above say that the line input bypasses the preamp?

7. "A passthrough connector is a second output, sometimes simply connected to the input connector, that delivers the input signal unchanged, to allow the DI unit to be inserted into a signal path without interrupting it. This is essential in many applications." Why would you want to use a passthrough, since it outputs exactly the same signal as you inputted? Wouldn't this render the device useless since it just bypasses the signal?

Thanks!

 

[fuzzrhythm]

Someone please correct me if I'm wrong about anything. We're all always learning...

1. The POD and other amp modelers are pre-amps. They can be plugged into a power amp or line in and pass a good signal.

2. It says it bypasses the mic preamp. Perhaps the mic preamp and instrument preamp are different?

3. XLR and 1/4" can both be pre-amped. Any time you have something that is not yet at line level (passive instrument....guitars, basses, mics) needs to be pre-amped.

4. Yes.

5. DI boxes give a balanced XLR signal typically for long cable runs used in live sound and large studios. It can also change the tone of a guitar/bass/whatever signal. The XLR will go to a mic pre-amp on the mixing board/PA most likely.

6. I'm not totally clear on the difference between active and passive DI boxes, myself. I play bass with passive pickups, so from what I understand, I need and active DI box to boost the signal more.

7. To split the signal. You'd place the DI box before anything else in your chain (POD for example) to send the main XLR output to the mixer, then the other unaffected 1/4" output through to your POD and on to your amp. You might then mic your amp, or go straight out of your POD into the mixer as well. This way you can blend a clean tone and an affected tone for more mixing options.

 

[ahrenba]

Awesome! Thanks for your reply! Good stuff!

Just a couple follow up questions.

1. The POD and other amp modelers are pre-amps. They can be plugged into a power amp or line in and pass a good signal.

Does this mean that it outputs a line level signal, instead of instrument or mic level?

3. XLR and 1/4" can both be pre-amped. Any time you have something that is not yet at line level (passive instrument....guitars, basses, mics) needs to be pre-amped.

Ok. This makes sense. However, I have heard that some people record by plugging directly in to the hi-z or line-input on a mixer, and this can produce a workable signal, is this true?

5. DI boxes give a balanced XLR signal typically for long cable runs used in live sound and large studios. It can also change the tone of a guitar/bass/whatever signal. The XLR will go to a mic pre-amp on the mixing board/PA most likely.

Do you lose and frequency response since you are converting the signal to a balanced XLR signal?

6. I'm not totally clear on the difference between active and passive DI boxes, myself. I play bass with passive pickups, so from what I understand, I need and active DI box to boost the signal more.

Where does your DI Box fit in your chain? Do you output an XLR cable or 1/4" cable? From what I have read, it looks like active DI boxes are indeed preamps, but I can't see how it would preamp the signal, if it uses a passthrough like described above.

What exactly would you use a passthrough connection for? I mean, isn't this essentially bypassing all the functionality of the DI box or Preamp? Is a passthrough actually preampped?

Also, would an effects pedal, such as the Boss DS-1 Distortion pedal be considered a preamp? If so, does it output a line level signal? The reason I ask is because it has a "gain" knob, which is a common characteristic of preamps.

Thanks!!

 

[Oancient1]

My 2 cent response to the original post.

1. If the processor amplifies, it'll tell you so, although maybe not directly. I use a Digitech multi effects processor that has two settings one for connecting instument input, one for connecting to LINE input. I have used it both ways, but use the LINE mode exclusively when recording. When I use the Digitech through my amp, even the instrument setting seems to provide some amplification on some effects settings.

2. The statement sounds like weasal wording to me. Often amplifiers (and these preamps are still amplifiers after all) have multiple stanges inside, in which case the first stage is called a "preamp" stage, so perhaps they are trying to imply that there is a separate first stange for the the mic input that is bypassed in the instrument input signal change. But note that what was supposedly bypassed is the "mic preamp circuitry", which doesn't necessarily mean any amplification is bypassed.

3. Of course they boost signals from either input, but by different amounts. You can see the max gain for all cases in the spec section of the manual available at the first the link you posted.

4. My answer is sometimes yes on guitar. On my inexpensive recorder, it is often a challenge to get a high enough level on the recorded track when I plug directly into the recorder and use certain of its internal effects, so I use a preamp into the recorders LINE input and then there are no problems. I have also heard preamplification is needed for long cable runs to a sound board, in which case I would say the preamp becomes an active DI box per your next question.

5. I am sure others here know more than me on this one. My understanding is that a passive DI box matches the impedance of the guitar with the input impedance of the mic input to a recorder or sound board. I have no idea how. As for improving the sound, the device you referenced uses a vaccuum tube to supposedly provide the "tube amp" warmth that is missing when an instrument goes direct in to the solid-state front end of a recorder or sound board, and has a knob with different "warmth settings" for different instruments. My Behringer preamp works the same way, and the knob does change the sound.

6. I would assume so, but I don't know DI boxes

7. I assume the application here is a live show where a bass player or keyboard player wants to provide a direct input to the sound man/recording engineer while simutaneously plugging into an amp onstage, thus allowing the sound guy easier control of volume and tone than he woul have inf miking the amp. To which as a guitar player I say, over my dead body unless its on the other side of whatever effects box I am using.

Tom

 

[ahrenba]

Thanks for the replay, Oancient1!

If anyone has time, could you take a look at the questions I posed in post #3? Thanks!

Also, those preamps I linked too all have a knob for input level and output level? What does each do and why do you need one for each?

Also, why are preamps always listed as Mic Preamps, and not guitar preamps, etc.?

 

[60's guy]

Also, those preamps I linked too all have a knob for input level and output level? What does each do and why do you need one for each?

The input level knob on that Art pre you linked is simply a GAIN adjustement you use to boost/control the level you are delivering to the preamp from your source (guitar / microphone etc) at a consistent level without clipping the unit.

The output level knob controls the signal strength that is delivered to a destination.....recorder.

If you plan to make a purchase and you are researching it online...it's always a good idea to download the pdf file of the operating manual for the unit you are considering to purchase. It's a quick and free method to familiarize yourself with the equipment before you lay your money down.

 

[Farview]

My turn

1. Is an effects processor (such as the Line6 POD) considered a preamp? I realize that it "tone-shapes" the signal to match cabs from different eras, but is it technically a preamp (boosts signal)?

Yes. The Pod puts out a line level signal. The Pod pro puts out a line level balanced signal

2. Look at this Product:
http://www.musiciansfriend.com/product/ART-Tube-MP-Studio-Mic-Preamp?sku=180581
It says: "High impedance instrument input bypasses the mic preamp circuitry for a shorter signal path. " Since this means that the instrument input bypasses the preamp, what is the use for plugging it in, in the first place?

Impedance matching and balancing. There is also a line amp in there (the output knob) to turn the record level up and down.

3. In conjunction with the question above, do preamps ONLY boost signals from XLR inputs, or can they boost signals from 1/4" inputs also? The reason I ask is because the quote above makes it seem like the instrument signal should be bypassed. Maybe someone could explain this.

They will boost signals from both. The 1/4 input won't have as much boost as the xlr.

4. Do instrument outputs (such as from a guitar) need to be preampped?

Normally. Some active pickups put out enough signal, but it's still nice to have some control over the levels.

5. DI Boxes.....Look here: http://www.musiciansfriend.com/product/ART-Tube-MP-Studio-V3-Mic-Preamp?sku=180610
"Also can serve as an exceptional direct box for impedance matching or simply improving the sound of any instrument plugged into it."
This is listed as a preamp...what makes it a DI Box, and what is the benefit of a DI box other than it converts a 1/4" input to an XLR output (balanced)? Does it change the tone like a preamp would? Was does it bypass the mic preamp? Is it still going to be preampped?

That is a preamp with a DI built in. Meaning: It impedance matches the signal and brings it to line level. This isn't just a DI, it's both.

6. Is an active (powered) DI box considered a preamp? If so, why does the info above say that the line input bypasses the preamp?

No, a stand alone DI takes an unbalanced hi impedance signal and turns it into a balanced low impedance signal. You are getting confused because you are not looking at DI boxes, you are looking at preamps.

7. "A passthrough connector is a second output, sometimes simply connected to the input connector, that delivers the input signal unchanged, to allow the DI unit to be inserted into a signal path without interrupting it. This is essential in many applications." Why would you want to use a passthrough, since it outputs exactly the same signal as you inputted? Wouldn't this render the device useless since it just bypasses the signal?

The passthrough is so that you can plug into your amp while you are getting the direct signal from the guitar recorded. The guitar plugs into the DI. The passthrough of the DI plugs into the amp. Then you mic the amp and record both the mic signal and the direct signal from the guitar.

 

[ahrenba]

Wow. Thanks for all the help guys.

60's Guy:

The input level knob on that Art pre you linked is simply a GAIN adjustement you use to boost/control the level you are delivering to the preamp from your source (guitar / microphone etc) at a consistent level without clipping the unit.

The output level knob controls the signal strength that is delivered to a destination.....recorder.

How can you control how strong the signal is coming from a guitar to the preamp? Isn't it solely determined by the amount of voltage the pickups are putting off? I guess I just don't see why there isn't just one knob, that controls how much signal you are eventually outputting, because isn't that all you really care about?

Farview

That is a preamp with a DI built in. Meaning: It impedance matches the signal and brings it to line level. This isn't just a DI, it's both.

How exactly does it impedance match the signal? Does it just regulate the output impedance so that it matches that of the load (i.e. mixer input)? So, is a DI box solely defined by taking a instrument input and outputting it as a balanced (i.e. XLR) signal?

My remaining question: "Also, would an effects pedal, such as the Boss DS-1 Distortion pedal be considered a preamp? If so, does it output a line level signal? The reason I ask is because it has a "gain" knob, which is a common characteristic of preamps."

Also, does converting a instrument signal down to a XLR signal cause any frequency loss, rolloff or distortion on the signal?

 

[60's guy]

How can you control how strong the signal is coming from a guitar to the preamp? Isn't it solely determined by the amount of voltage the pickups are putting off? I guess I just don't see why there isn't just one knob, that controls how much signal you are eventually outputting, because isn't that all you really care about?

The purpose of a preamp isn't to control the output signal from a guitar or microphone. The source signal strength is what it is.

A preamp simply amplifies that signal to an acceptable level to deliver to a recorder or for additional amplification.

Have you ever plugged your guitar into an amp that has pre and post gain knobs?

 

[ahrenba]

The purpose of a preamp isn't to control the output signal from a guitar or microphone. The source signal strength is what it is.

A preamp simply amplifies that signal to an acceptable level to deliver to a recorder or for additional amplification.

Have you ever plugged your guitar into an amp that has pre and post gain knobs?

Ok, so I realize that a preamp amplifies the signal to line level so that it can be recorded etc.

So if you have guitar -> preamp -> recorder , does the input knob actually control the physical "boosting" of the signal, while the output knob just regulates that boosted signal? By this I mean, does the input boost the signal to a certain level, and then the output knob regulates how much of this "boosted" signal you want passed on to the mixer, etc.?

Remaining questions:

Farview

That is a preamp with a DI built in. Meaning: It impedance matches the signal and brings it to line level. This isn't just a DI, it's both.
How exactly does it impedance match the signal? Does it just regulate the output impedance so that it matches that of the load (i.e. mixer input)? So, is a DI box solely defined by taking a instrument input and outputting it as a balanced (i.e. XLR) signal?

My remaining question: "Also, would an effects pedal, such as the Boss DS-1 Distortion pedal be considered a preamp? If so, does it output a line level signal? The reason I ask is because it has a "gain" knob, which is a common characteristic of preamps."

Also, does converting a instrument signal down to a XLR signal cause any frequency loss, rolloff or distortion on the signal?

 

[Farview]

Farview


How exactly does it impedance match the signal? Does it just regulate the output impedance so that it matches that of the load (i.e. mixer input)? So, is a DI box solely defined by taking a instrument input and outputting it as a balanced (i.e. XLR) signal?

In an active DI, the DI employs a buffer circuit that isolates the input from the output. The mic preamp only sees the impedance of the buffer circuit.

In a passive DI, a transformer is used to chnange the impedance and level.

A DI box converts a high impedance unbalanced signal into a low impedance balanced signal. That's it.

My remaining question: "Also, would an effects pedal, such as the Boss DS-1 Distortion pedal be considered a preamp?

Anything that amplifies a signal prior to feeding something else is a preamp. Is it a mic preamp, no.

If so, does it output a line level signal? The reason I ask is because it has a "gain" knob, which is a common characteristic of preamps."

It can put out a line level signal if you feed it enough signal. The amplifier in that pedal only has so much gain, so if you feed it a signal loud enough, the amp will have enough gain to bring the signal up to line level.

If it has a gain knob, it's an amplifier. What it's designed purpose is will determine whether it's a 'preamp' or not.

Also, does converting a instrument signal down to a XLR signal cause any frequency loss, rolloff or distortion on the signal?

It depends on how you do it. A passive pickup going through a passive DI will load down the pickup and you will get frequency loss. If you use an active DI in that situation, you will not get any frequency loss.

 

[ahrenba]

Ah! Thanks for the explanation, makes sense!!.

Just thought of a quick question:

1. On something such as a TonePort UX1, why is it that you do not need to preamp the signal for an instrument? I realize it has an instrument input, but isn't it too low of a level to work with? I understand the mic (XLR) input on that TonePort has a preamp, but the instrument input does not.

2. How many simultaneous channels of audio can the TonePort record in your software?

Remaining question:

The purpose of a preamp isn't to control the output signal from a guitar or microphone. The source signal strength is what it is.

A preamp simply amplifies that signal to an acceptable level to deliver to a recorder or for additional amplification.

Have you ever plugged your guitar into an amp that has pre and post gain knobs?

Ok, so I realize that a preamp amplifies the signal to line level so that it can be recorded etc.

So if you have guitar -> preamp -> recorder , does the input knob actually control the physical "boosting" of the signal, while the output knob just regulates that boosted signal? By this I mean, does the input boost the signal to a certain level, and then the output knob regulates how much of this "boosted" signal you want passed on to the mixer, etc.?

 

[Farview]

1. On something such as a TonePort UX1, why is it that you do not need to preamp the signal for an instrument? I realize it has an instrument input, but isn't it too low of a level to work with? I understand the mic (XLR) input on that TonePort has a preamp, but the instrument input does not.

The instrument input is acting as a DI and a preamp. You are just getting confused because you are looking at all-in-one units. If you were looking at discrete units, you would need:
1. DI to convert your unbalanced high impedance signal to low impedance balanced
2. Mic preamp to adjust the gain up to line level
3. Analog to digital converters to convert the analog signal into digital for mixing and editing in the computer.

All of those things, plus an amp simulator, are combined into one unit in the toneport.

2. How many simultaneous channels of audio can the TonePort record in your software?

My best guess would be one. But, I don't know. There is only two inputs on it, so that would be the highest possible track count.

Remaining question:


Ok, so I realize that a preamp amplifies the signal to line level so that it can be recorded etc.

So if you have guitar -> preamp -> recorder , does the input knob actually control the physical "boosting" of the signal, while the output knob just regulates that boosted signal? By this I mean, does the input boost the signal to a certain level, and then the output knob regulates how much of this "boosted" signal you want passed on to the mixer, etc.?

You could look at it that way. It really depends on the preamp, not all of them have two knobs.

Sometimes one knob will just be the volume for your headphone mix and not have anything to do with the recording level.

Sometimes the preamp will be made so you can overdrive the preamp, then use the output knob to bring the output level back down.

Sometimes there is an insert point between the preamp and the output that allows you to put an EQ, compressor, etc... in the chain, the output knob will allow you to adjust the level after the processor.

 

[ahrenba]

Awesome. Your answers are great!

The instrument input is acting as a DI and a preamp. You are just getting confused because you are looking at all-in-one units. If you were looking at discrete units, you would need:
1. DI to convert your unbalanced high impedance signal to low impedance balanced
2. Mic preamp to adjust the gain up to line level
3. Analog to digital converters to convert the analog signal into digital for mixing and editing in the computer.

All of those things, plus an amp simulator, are combined into one unit in the toneport.

1. So let me see if I get this right. The instrument input (in actuality) is preamped because the wiring inside the TonePort makes it so that the instrument input is converted to a balanced signal (DI-like functionality), which then goes through the mic preamp and into the computer? Is this right? Or is the instrument input not preampped at all?

2. If my logic was correct above, what would happen if I have a instrument and a Mic plugged into the TonePort. Since it only has one preamp (mic), would/could it use that one preamp to boost both inputs?? Thanks!!

Thanks for the explanation on those knobs.

3. Oh, and one other thing. I just looked at my Boss DS-1 Distortion Pedal, and realized that it has a Tone, Distortion, and Level knob. Is the level knob the same as a "gain" knob....therefore providing preamplification?

4. Also, with a standalone preamp (like that ART one), can you only plug one source into the preamp? I know that you can output something like an XLR AND 1/4", but can you input two different signals (like a mic and guitar) at the same time and have both preampped? I would assume the answer would be no...

5. When I think about that "bypasses the mic preamp" for high impedance inputs, I am just wondering how exactly it works. Would the instrument input normally have to be wired through the mic preamp and then to another instrument input preamp? This doesn't really make sense to me....

Sorry for all the questions....more just keep popping into my head!

 

[Farview]

1. So let me see if I get this right. The instrument input (in actuality) is preamped because the wiring inside the TonePort makes it so that the instrument input is converted to a balanced signal (DI-like functionality), which then goes through the mic preamp and into the computer? Is this right? Or is the instrument input not preampped at all?

That depends on how they designed it. If there is a volume or gain control that controls the instrument input, then it is preamped. That doesn't mean that the instrument goes through the same preamp that the mic does.

2. If my logic was correct above, what would happen if I have a instrument and a Mic plugged into the TonePort. Since it only has one preamp (mic), would/could it use that one preamp to boost both inputs?? Thanks!!

If it only has one preamp, it won't let you do both. This is something you would have to look up in the manual.

3. Oh, and one other thing. I just looked at my Boss DS-1 Distortion Pedal, and realized that it has a Tone, Distortion, and Level knob. Is the level knob the same as a "gain" knob....therefore providing preamplification?

It might be gain or it might be attenuation. It depends on how it was designed. It really doesn't matter.

4. Also, with a standalone preamp (like that ART one), can you only plug one source into the preamp? I know that you can output something like an XLR AND 1/4", but can you input two different signals (like a mic and guitar) at the same time and have both preampped? I would assume the answer would be no...

No, they are just giving you two cabling options. The output is the same to both the XLR and the 1/4

5. When I think about that "bypasses the mic preamp" for high impedance inputs, I am just wondering how exactly it works. Would the instrument input normally have to be wired through the mic preamp and then to another instrument input preamp? This doesn't really make sense to me....

Normally, a DI box will attenuate the signal while it is changing the impedance. The DI box is designed to be plugged into a mic preamp, that's why the impedance needs to be lowered.

When designing an all in one unit, they don't have to go through all of the same steps. They can just design a circuit that converts it from an instrument signal to a line signal. There might be some amplification involved, but it won't be the mic preamp. (in that instance)

 

[ahrenba]

That depends on how they designed it. If there is a volume or gain control that controls the instrument input, then it is preamped. That doesn't mean that the instrument goes through the same preamp that the mic does.

1. In the case of the TonePort UX1, http://www.musiciansfriend.com/prod...X1-USB-RecordingModeling-Interface?sku=249700 , there is only a knob for the "Mic Level". So, does this mean that the instrument input is not preamped? If so, how is the signal loud enough to work with.

If it only has one preamp, it won't let you do both. This is something you would have to look up in the manual.

2. Ok, I found out that with the TonePort you can hook up a mic and instrument and record simultaneously. So, wouldn't this mean that both inputs would have to be preampped?

It might be gain or it might be attenuation. It depends on how it was designed. It really doesn't matter.

K, just looked up the specs for this pedal:
Nominal Input Level
-20 dBu
Input Impedance
470 ohms
Nominal Output Level
-20 dBu
Output Impedance
1 k ohms
Equivalent Input Noise Level
-122 dBu (IHF-A, Typ.)
Connectors
INPUT Jack, OUTPUT Jack, AC Adaptor Jack (9 V DC)
Power Supply
9 V DC: Dry Battery 9 V type, AC Adaptor
Current Draw
4 mA (9 V DC)
Accessories
Dry Battery 9 V type (6F22/9 V)
Options
AC Adaptor (PSA-Series)

3. Why does it have such a low input impedance?? Shouldn't it be a hi-z input to get the most voltage from the guitar?? So, hmm...it looks like it doesn't boost the signal since the nominal input and output level are the same (-20dBu)....so would this be attenuation?

No, they are just giving you two cabling options. The output is the same to both the XLR and the 1/4

4. What I was trying to address with the question was weather you can plug two different inputs into a preamp (the ART for example) and have them both be preammped, or if you can only do one at a time?

Normally, a DI box will attenuate the signal while it is changing the impedance. The DI box is designed to be plugged into a mic preamp, that's why the impedance needs to be lowered.

When designing an all in one unit, they don't have to go through all of the same steps. They can just design a circuit that converts it from an instrument signal to a line signal. There might be some amplification involved, but it won't be the mic preamp. (in that instance)

5. Ah! Ok, that makes sense about the DI box. So basically it'll take the input, will not amplify it, and output it through a balanced XLR signal? Hmmm...wouldn't that be a sort of waste of a preamp, since in actuality, you will just be using it as a DI box to go into another preamp?

Wow, thanks for your help, man. I really appreciate it. I apologize for all my questions (they may be repetitive), but I really like to grasp the knowledge and concepts that I'll be working with.

 

[Farview]

1. In the case of the TonePort UX1, http://www.musiciansfriend.com/prod...X1-USB-RecordingModeling-Interface?sku=249700 , there is only a knob for the "Mic Level". So, does this mean that the instrument input is not preamped? If so, how is the signal loud enough to work with.

That knob might still affect the instrument level. There just isn't room to label it.
You might want to download the manual. I don't have a toneport, I just know what is involved in making these things work.

2. Ok, I found out that with the TonePort you can hook up a mic and instrument and record simultaneously. So, wouldn't this mean that both inputs would have to be preampped?

Yes, but through different preamps.

K, just looked up the specs for this pedal:
Nominal Input Level
-20 dBu
Input Impedance
470 ohms
Nominal Output Level
-20 dBu
Output Impedance
1 k ohms
Equivalent Input Noise Level
-122 dBu (IHF-A, Typ.)
Connectors
INPUT Jack, OUTPUT Jack, AC Adaptor Jack (9 V DC)
Power Supply
9 V DC: Dry Battery 9 V type, AC Adaptor
Current Draw
4 mA (9 V DC)
Accessories
Dry Battery 9 V type (6F22/9 V)
Options
AC Adaptor (PSA-Series)

3. Why does it have such a low input impedance?? Shouldn't it be a hi-z input to get the most voltage from the guitar?? So, hmm...it looks like it doesn't boost the signal since the nominal input and output level are the same (-20dBu)....so would this be attenuation?

Nominal means that it was measured at unity, so it could still be boosting. As far as impedance goes: because it was designed that way. It obviously works for its intended use, it's been in production for over 20 years. Remember that its intended use was to use in front of a guitar amp, not to be used as a direct box.

4. What I was trying to address with the question was weather you can plug two different inputs into a preamp (the ART for example) and have them both be preammped, or if you can only do one at a time?

You can only plug one thing into a preamp at a time. One box (like the toneport) may have more than one preamp in it. That would allow you to plug two things into the box.

5. Ah! Ok, that makes sense about the DI box. So basically it'll take the input, will not amplify it, and output it through a balanced XLR signal? Hmmm...wouldn't that be a sort of waste of a preamp, since in actuality, you will just be using it as a DI box to go into another preamp?

I'm not sure you understood what I was saying.

Circumstance A : Bass player on stage with an active bass plugs into a passive direct box and plugs the passthrough into his bass amp. The xlr is fed into the snake and hooked into a mic preamp on the board.
In this instance, the signal coming out of the bass goes into the DI box and is attenuated, balanced and the impedance is lowered. The signal is now, for all intents and purposes, a mic signal. It is fed into the mic preamp on the mixer which brings it up to line level to run to the PA or the recorder.

Circumstance B: Bass player plugs into the instrument input on a firewire recording interface to record.
In this instance, the signal comes out of the bass and goes into the high impedance input of the unit. Once in there, anything can happen. It all depends on the design of the unit. It could balance the signal, but there is no point because the signal isn't going to leave the unit until it's digital. (most pieces of audio equipment are not balanced all the way through. The inputs and outputs are balanced so you don't pick up rf noise along the cable runs. Internally, that isn't a problem)
It could amp the level up to line level, but it could also just have the converter calibrated to instrument level.
It really doesn't matter. It just works.

 

[ahrenba]

Alright, cool. Thanks for you help man. I appreciate it!

I have been scouring TonePort's manuals, and they are extremely hard to interpret. I cannot find any info about how the preamp situation works in that thing. They mainly have manuals for their GearBox software, but not the hardware itself.

Anyone have any insight?

Here are their manuals: http://line6.com/support/manuals/?families=28&submit=Submit&1st=1st

 

[Farview]

I have been scouring TonePort's manuals, and they are extremely hard to interpret. I cannot find any info about how the preamp situation works in that thing. They mainly have manuals for their GearBox software, but not the hardware itself.

You may just have to have faith that it was designed to work correctly. It has to give you control over the instrument input.

 

[ahrenba]

Ok, I am back with another quick question.

Let's use the Lexicon Omega as a reference:
http://www.musiciansfriend.com/product/Lexicon-Omega-Desktop-Recording-Studio?sku=245505

Manuals are here: http://www.lexiconpro.com/ProductDownloads.aspx?ProductID=6&Type=4

This has two preamps (one on each mic input). It also has 4 line inputs and one instrument input.

Now, there are "gain" knobs for both the mic inputs and all the line/instrument input(s).

This is where my questions lies. Doesn't "gain" mean the signal is being boosted? If so, how can there be a "gain" knob on the line/instrument inputs if they do not have preamps? What are they actually doing? Thanks!