[linux-audio-user] Bass V-amp vs V-amp

[Jean-Baptiste Mestelan]

Thanks Paul and Cesare.

I use the jack input on my mixing console.
The soundcard is a Delta 44, which has no preamps, and will accept a
line-level signal.

Sorry, but I've never really understood too well impedance issues :-/

I just found this on the web, which suggests that an active bass
(which I got) already has low-Z output, and therefore requires no DI ?
http://www.whirlwindusa.com/ftp/tech/tech03.pdf

A high impedance line that is interacting with outside electrical
interference will act more like an "antenna" than a low impedance
line. This problem can get worse as the cable gets longer. This effect
is usually insignificant for a guitar or high-Z microphone plugged
into an amp with a 15' cord but it can have a big effect if that same
signal is sent 100' down a snake. These are reasons why a high
impedance signal is almost always converted to low impedance with the
use of a Direct Box (DI) before being sent long distances.

Another reason for the use of a DI is that it takes a two conductor
unbalanced line and converts it to a three conductor balanced line.
This is a separate issue, not to be confused with impedance. It is a
common misconception that all lines that use regular tip/sleeve ¼"
guitar cord type connectors are high impedance. Not so. The output
from a guitar that has a battery operated active preamplifier or
pickup system will be low impedance in nature. So will the output of
an electronic keyboard, guitar preamplifier or guitar effects
processor. The signals are unbalanced but LOW impedance in nature.

On 8/10/06, Paul Coccoli <pcoccoli at gmail.com> wrote:
> On 8/10/06, Jean-Baptiste Mestelan <mestelan at gmail.com> wrote:
> > I wondered if I such a  DI box would make sense in my recording setup :
> > bass ---> mixing console ---> soundcard
> >
> > How useful would it be to insert a DI  ?
> > bass ---> DI --> mixing console ---> soundcard
> >
> > A guitarist friend of mine has tried to convince me so, but I did not
> > exactly grasp the whole argument ... I would have thought that the
> > console already serves as a preamp, but I may miss some point ?
> >
> > Thanks for advice.
> >
>
> It should sound better using a DI since it will match the impedance.
> What type of input are you using on the mixing console?
>
> Borrow your friend's DI to hear the difference for yourself.
>