I want to modify a bit more my bass sound by using the amplitube VST before sending it to my amp.

The scarlett 2i4 has RCA outputs, and my bass amp (Ampeg BA108) has a CD input (RCA) and effect loop inputs (1/4" Jack, RETURN & SEND) and the classic jack inputs.

So which input should i use? classic jack input, CD, return or send?

  • Couldn't you use the send & return to add the effects (Amplitube) signal to the amp? I'd check I/O levels in manuals first though, because I'm not sure.
    – n00dles
    Sep 13, 2015 at 4:49

2 Answers 2


I like the idea, but you will want to keep impedance in mind. The thing to remember here is that your bass is outputting an instrument level signal, and your bass amp is designed to handle that signal.

When you run the bass through the scarlett though, it is accepting your instrument level signal from the bass, processing through the VST, and being output as a line level signal through your scarlett's RCA outputs. Since line level signals can potentially run a lot hotter than instrument level signals, you could risk damaging your amp.

It might not be a good idea to feed your amp a line level signal through its input jack or its send/returns. Lucky for you though, it does have a CD (RCA) input that is designed to handle line level signals.

So your solution looks like:

  • Bass into Scarlett
  • Scarlett RCA into CD input on amp

You may find that your amp just doesn't sound as nice when you are feeding it a line level signal through the RCAs. Luckily, you can get a re-amping box similar to what producers use in the studio for reamping guitars. This box will convert a line level signal to an instrument level signal so that it gives the amp the signal it expects.

Then your configuration could look like this:

  • Bass into Scarlett
  • Scarlett RCA into Reamp Box
  • Reamp Box into Bass amp input

Here are a couple of links that explain re-amping (which is super applicable to your situation):




The CD input on most amps doesn't use the pre-amp section or EQ, it's just fed to the last part of the amplification and in to the speaker at maximum volume.

What that means is that you'll have to change the volume of the feeding signal from amplitube. So in essence you will be using only the speaker of your bass amp.


Some info, the RCA cables are unbalanced which means you'll have to cope with -6db output.

The Amp gets Hi-Z signal from the instrument and is designed to work that way.

I don't want to get too technical about it but it concerns impedance and levels as said before.

Now if you really want to integrate your bass amp with your scarlett the signal flow goes like this:

1.Bass Guitar -> 2.Scarlet 2i4 Instrument input -> 3.Amplitube -> 4.Balanced monitor output (left or right) -> 5.Re-amp Box (http://www.radialeng.com/prormp.php) -> 6.Bass Amp

so about step 4: Your scarlett has 2 outputs that feed signal into your monitor setup, These are balanced connections and feed line signal to your Active monitors. You can configure from your DAW the output of the amplitube channel to be one of these two outputs, So to do this right you'll have to "sacrifice" stereo monitoring , feed the whole mix to the one channel (if you are doing it for recording purposes) and reamp the other channel.

If you want to keep sending from your RCA channel i would recommend before you go to your re-amp box to use an Unbalanced To Balanced signal converter (http://www.bswusa.com/Hum-Reduction-Rolls-BUZZOFF-P4661.aspx) This will make a much healthier signal to feed into the amp, but costs some money too.

So What you are after is a reamping process as Johannes stated before, either you record it afterwards or not.You can find countless posts concerning this matter on the internet.

Also one matter you must have figured out by now is the latency of your card.

Good luck.

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