Bass amp head as pre-amp?

[RecordingMaster]

Here's the basic setup for this application:

- TASCAM US-1800 audio interface: it has inputs with and without preamps. The ones without preamps are intended for connecting an external preamp.
- I do have an external pre amp as well for a different flavor, called the ART MPA Pro II. It has High Z guitar inputs or balanced xlr inputs.
- The above goes into my iMac OSX via USB 2.0
- I am using Pro Tools 9
- Bass amp head in question is a Galien-Krueger Backline 600 with a "Direct Out" XLR jack on the front panel

My blunders, my bass player has a bass guitar with ACTIVE pickups, meaning going direct into a Hi-Z jack is bad because it is meant for passive pickups. So to DI the bass, I usually go into a passive DI and out of the XLR out, into the XLR in on my interface. And I use the pre amp on the interface to adjust the recording level. Alternatively, I'll go into the outboard pre-amp's XLR IN jack, then from there into the passive input on my interface.

My questions are for 2 different scenarios:

1) Let’s say I want to use the GK 600 simply as a DI box rather than my low quality passive Yorkville DI. I would go into the GK head, out of the Direct out (in EQ BYPASS mode), then into the pre amp on my interface (or outboard pre) to adjust recording level. Alternatively, could I go from the XLR out into a 1/4" Hi Z jack on either the interface or outboard pre? Or would that still be bad since the bass is active in which case i'd stick to the original thought of going into theXLR balanced jack?

2) Let’s say I want to use the GK 600 as a DI AND have the flavor and sound of the GK. I would go into the GK, out of the direct out (in EQ ‘ON’ mode), then into the TRS passive input on my interface, bypassing the interface’s preamps. I’d assume the MASTER control on the GK would as as the pre-amp volume. Am I correct? For the record, GK says with EQ ON mode, it will give you that GK sound AND it's pre-amp volume. I'm just scared I might blow something in my interface or monitors, etc.

Please let me know if you can answer those questions and if during any of the above scenarios, if I would ever need to go from the GK into the Hi Z input on my interface (or if that's not an option since it's an active bass and it would mess with the signal).

Thanks so much for your help! As always.

 

[somegeezer]

DI is a line level signal. You don't plug a DI signal into a hi-z input.

Also, a Hi-z input should take active pickups fine, if you were to go direct from the bass, but as DI sends out line level, you should need to use a line input.

I use a 1001RB-II myself, and like to use my DI with EQ on. Mainly because my bass sounds terrible on its own. =P But I'll tell you that mic'ing up the cab is really going to make a difference in sound than just the EQ being set on in the DI.
Also, the master volume is for the woofers [the power amp]. The input volume is the preamp, and I'm not sure if the backline 600 has one, but there is a DI level on mine.

 

[RecordingMaster]

DI is a line level signal. You don't plug a DI signal into a hi-z input.

Also, a Hi-z input should take active pickups fine, if you were to go direct from the bass, but as DI sends out line level, you should need to use a line input.

I use a 1001RB-II myself, and like to use my DI with EQ on. Mainly because my bass sounds terrible on its own. =P But I'll tell you that mic'ing up the cab is really going to make a difference in sound than just the EQ being set on in the DI.
Also, the master volume is for the woofers [the power amp]. The input volume is the preamp, and I'm not sure if the backline 600 has one, but there is a DI level on mine.

Thanks.

One thing I disagree with is "a Hi-z input should take active pickups fine, if you were to go direct from the bass". I've asked about this on here before. As far as I'm aware, Hi Z is for something passive with very low impedance. But active pickups are not the same impedance as passive ones, they are line level. Therefore it will boost the signal of the basstoo much, cutting off important high freq information and adding a clicky/poppy sound the signal. I;ve tried it and this is very true in my case.

So I guess now I'm wondering, if I DO use the EQ ON mode on the GK 600 (there is no direct out level), do I send the signal into an input with a pre-amp, or an input that bypasses the pre-amp? I'm assuming the latter. I'll try and see how it works, but I just want to do these things the right way. I know in recording there is no RIGHT way, but when it comes to things like this that involve ohms and voltage, I tend to believe there only ONE way of doing it.

EDIT: Ps, I do plan on mic'ing the cab as well. I just always like to run a DI just in case, or to blend.

 

[somegeezer]

Thanks.

One thing I disagree with is "a Hi-z input should take active pickups fine, if you were to go direct from the bass". I've asked about this on here before. As far as I'm aware, Hi Z is for something passive with very low impedance. But active pickups are not the same impedance as passive ones, they are line level. Therefore it will boost the signal of the basstoo much, cutting off important high freq information and adding a clicky/poppy sound the signal. I;ve tried it and this is very true in my case.

So I guess now I'm wondering, if I DO use the EQ ON mode on the GK 600 (there is no direct out level), do I send the signal into an input with a pre-amp, or an input that bypasses the pre-amp? I'm assuming the latter. I'll try and see how it works, but I just want to do these things the right way. I know in recording there is no RIGHT way, but when it comes to things like this that involve ohms and voltage, I tend to believe there only ONE way of doing it.

EDIT: Ps, I do plan on mic'ing the cab as well. I just always like to run a DI just in case, or to blend.

You're right, they aren't the same, but they handle it fine. You're not going to damage anything doing it.

and you're going to need to send the line level signal into a line input, which is already run by a preamp. Generally the volume knob/slider will have a unity [0] point. Mine go between -20 and +20, so as close to unity as you can is best for best quality signal. Can always adjust so it's not too loud or too quiet with the mixer.

 

[Mo Facta]

Thanks.

One thing I disagree with is "a Hi-z input should take active pickups fine, if you were to go direct from the bass". I've asked about this on here before. As far as I'm aware, Hi Z is for something passive with very low impedance. But active pickups are not the same impedance as passive ones, they are line level. Therefore it will boost the signal of the basstoo much, cutting off important high freq information and adding a clicky/poppy sound the signal. I;ve tried it and this is very true in my case.

There is only about 15dB difference (at the most) between the level of passive and active basses. The GK600 has a -10dB pad which should compensate for the increase in level. You know this button is supposed to be depressed when an active bass is used, right? Doing so will restore proper gain structure and ensure a proper level output at the DI out.

As far as impedance goes, most active bass pickups are around 15 - 50 kOhms which is high (line level is a very low 600 Ohms). Passive pickups can be all the way up to 500 kOhms. These both fall into the "Hi-Z" category compared to true line level so using the Hi-Z input on your interface isn't going to harm it or the tone. If you have a pad on your preamp, use it (provided it works with the hi-z input) or merely start with the gain all the way down and increase as needed.

In the case of your dilemma, I would personally use the GK 600 with the pad on and take the DI signal out the XLR out and into a mic preamp.

Cheers

 

[RecordingMaster]

There is only about 15dB difference (at the most) between the level of passive and active basses. The GK600 has a -10dB pad which should compensate for the increase in level. You know this button is supposed to be depressed when an active bass is used, right? Doing so will restore proper gain structure and ensure a proper level output at the DI out.

As far as impedance goes, most active bass pickups are around 15 - 50 kOhms which is high (line level is a very low 600 Ohms). Passive pickups can be all the way up to 500 kOhms. These both fall into the "Hi-Z" category compared to true line level so using the Hi-Z input on your interface isn't going to harm it or the tone. If you have a pad on your preamp, use it (provided it works with the hi-z input) or merely start with the gain all the way down and increase as needed.

In the case of your dilemma, I would personally use the GK 600 with the pad on and take the DI signal out the XLR out and into a mic preamp.

Cheers

Thanks guys.

Mo, no I did not know that (use the pad with active bass in the GK). It's not my amp, it's the bassist's, so I rarely see the thing and haven't ever really known much about active/passive basses until somewhat recently. It's funny because we've been to other studios and other live venues where he has gone direct and the engineer or soundman never even paid any mind to bother asking whether or not it was passive or active. Maybe I care too much? No! It's the fact that no matter what I do, even going through a passive DI into my external pre with a low z setting, I still get clicky poppy sh*t! No amp sims or digital sansamps will fix it. Never have I had so much trouble recording bass until now with his damned custom made active bass (VERY well made by an acclaimed legend custom guitar maker in Canada)! Maybe it's the custom circuitry? I've tried explaining to him that maybe it's mostly suited for live and that professional musicians use certain instruments for live and certain for studio, but he's dead set on using it. He doesn't even own a single passive bass of the 5 that he has!

Sorry about the angry rant, but anyways... Yeah I think I'll go with your suggestion, Mo, and see what goes down. My whole point of this question was because I had a thought that perhaps going through an actual bass amp head would help in lowering the clicky/poppy/clangy nature on the recording. Because live through his amp and cab, it doesn't do that, although that could be the cab suppressing that. So I imaging the missing part of your suggestion was to have the EQ in OFF mode....or was it in ON mode? And if it is ON mode, shouldn't I bypass the preamps because I'll be using the pre-amp of the head? I liked the idea of EQ on mode, but I guess if I'm miking the cab too, then I'll have less control with the direct signal since there's only one output control for the cab's volume and the output signal. So best EQ off in that situation.

Oh the trials. This'll be the 4th attempt at recording his bass. Let's hope this time I can use something!

 

[Mo Facta]

Otherwise you could use a regular DI with the -20dB pad in. Most DI's have them.

Also, I'm starting to think this is not a level issue. The clickyness could be from the strings hitting the pickups. Check that out.

Oh, and let me guess. Is the bass a Kinal?

Cheers

 

[Guitargodgt]

clicky/poppy/clangy nature on the recording.

Sounds like the real issue you have is a bad bass player, not a bad bass. Even a passive will sound like ass if the player sucks at playing bass.

There is nothing worse than a bass player you finger picks his strings straight into the pickups. Sounds like ass no matter what bass you use.

The shitty technique is forgiving live when everything is mashed together though, plus the bass amp itself will mask some of those harsh clacks. But under the microscope of a studio setting it's shit every time.

Hopefully you can at least get him to change his strings and his battery, at least that would be a good start.

 

[RecordingMaster]

Follow up:
He changes his strings and is always checking the setup/intonation constantly. He's actually a phenomenal player and unlike the norm these days, plays BETTER with his fingers than a pick. He's been playing 15+ years so it was definitely not his technique. After trying about 10 different sets/styles of strings on his bass, he finally found "the one"! By which I mean the one that removed most of the annoying clickity clack of the strings. There is still just a little bit, but most DI basses always have SOME clang from finger playing. This is good since I'm blending it with the miked cab. The extra bit will help it stick out with more definition in the mix. The DI from the amp worked great with the pre EQ mode (EQ "off"), and then I had a separate signal with an AKG D112 just about 1.5" from the grill, pointed directly at the center of the cone. Tracked the D112 signal through a tube compressor only at about 3:1, and a tube pre amp. DI went dry through a tube pre-amp as well. Man does it sound great and I've got a lot to work with now! It sounds great as a standalone bass tone, but we'll see how it melds with the actual mix after I get in there and wrangle into submission with some EQ and compression.

I don't plan on doing too much to the cab track, as it's great and smooth on it's own. Just a bit of EQ and a slight bit more compression. But what do you guys usually do to your DI signal if you're blending it with the miked cab track? Do you use an amp sim? Or do you just keep it raw and maybe add some eq and compression? I was thinking I might try the latter first and see what it sounds like, with intent that leaving it dry will allow it to maintain it's very defined sound so it sticks out in the mix.

Is that what you do? If not, do tell what has worked best.

Thanks!

 

[Mo Facta]

Before you commit to the sound, try polarity reversing either the DI or the miked signal. There's a good chance the miked signal is out of phase with the DI. The simple reason for this is that the DI signal reaches the input at virtually the speed of light, while the miked signal has to go through the air first before it hits the transducer and therefore will be slightly delayed.

You will notice a huge difference in low end.

Cheers

 

[RecordingMaster]

Awesome thanks! For some reason I was only thinking that if you had 2 mics improperly placed on the instrument, that phase would ever be an issue. I will try it out and see what develops.

I assume this same principle would apply to when you DI + mic a regular guitar cab? Even though I have an amp sim running on the DI and have it eq'ed and panned separately from the mic track?

 

[somegeezer]

Awesome thanks! For some reason I was only thinking that if you had 2 mics improperly placed on the instrument, that phase would ever be an issue. I will try it out and see what develops.

I assume this same principle would apply to when you DI + mic a regular guitar cab? Even though I have an amp sim running on the DI and have it eq'ed and panned separately from the mic track?

I've heard you should always check for phase issues in mono before panning things out. But I have no idea if that's true.

 

[RecordingMaster]

Hmm. Well it sounds maginificent, and I can hear what I want to hear from both the DI and the cab. I did another take the same way for the other side of the same rhythm track. Panned the cabs hard left and right and the DI's around 50 R and 50 L. DI's were eq'ed to be thinner and dirtier, while the cab had a nice scooped tone and warmer, bassier sound. It's a perfect marriage.

In phase? Not sure, but who cares if the above is the result!

EDIT: And I DO check everything in mono. I have a feed coming from one of my headphone amp outputs going into a little clock radio with a mono speaker in it. Screw mix cubes! This one was only $5 (can you believe it actually had a Line-in jack and an AUX setting?) and gives me what I need: a reference for phase checking and to see how well things collapse into mono. From the sounds of my mixes in mono, they all collapse great. Never is the "cube" not voicing what is there in stereo. It's all about doing your due diligence and being responsible, I guess.

 

[somegeezer]

Hmm. Well it sounds maginificent, and I can hear what I want to hear from both the DI and the cab. I did another take the same way for the other side of the same rhythm track. Panned the cabs hard left and right and the DI's around 50 R and 50 L. DI's were eq'ed to be thinner and dirtier, while the cab had a nice scooped tone and warmer, bassier sound. It's a perfect marriage.

In phase? Not sure, but who cares if the above is the result!

EDIT: And I DO check everything in mono. I have a feed coming from one of my headphone amp outputs going into a little clock radio with a mono speaker in it. Screw mix cubes! This one was only $5 (can you believe it actually had a Line-in jack and an AUX setting?) and gives me what I need: a reference for phase checking and to see how well things collapse into mono. From the sounds of my mixes in mono, they all collapse great. Never is the "cube" not voicing what is there in stereo. It's all about doing your due diligence and being responsible, I guess.

If you have it sounding the way you want it to sound now, then nobody can really argue. =] I'm glad I've not delved into some of the more technical side of recording as of yet. =P