search

Audio-Injector / Ultra

Ultra sound card - 192khz, 24 bit, microphones and balanced line addon.
10 stars 1 forks source link

Can a guitar be connected directly to this board #15

Open bahamut657 opened 5 years ago

bahamut657 commented 5 years ago

Is it possible to connect directly an electric guitar and, integrating your hardware with some software, use the DSP to add effect to the guitar and bring out the sound to the guitar amplifier? I think guitar will input AC (but it is possible I'm wrong...).Is it supported? If not, have you some other boards to advise? (I see your homepage and see some different board types) This board got fantastic look!! Regards

Rippert commented 5 years ago

@bahamut657 - I don't have this soundcard, but have been looking at it. I do have the stereo audio injector which I use for exactly your application (but for Bass). I use a mixer with a High-Impedance input to buffer the guitar, and to change to the RCA connector which the Stereo card has standard.

Looking at the pictures of the Ultra card, you can almost certainly directly plug a guitar into the balanced input jack, but with a couple of issues.

First, you will be shorting one of the differential inputs to ground because a guitar cord has an unbalanced tip-sleeve connector, and the Ultra has a balanced tip-ring-sleeve connector. This is not necessarily a bad thing, but it does make the signal more prone to noise and ground loops.

Second, there will be an impedance mismatch. I can't find specs on the Ultra card input impedance, but, these types of pre-amps are typically set up with something like 50kohms, though that can vary quite a bit depending on the design. Your guitar, if it has passive electronics, is probably closer to 1Mohm. This mismatch will lead to a loss of both gain and brightness in the guitar signal. You could use a DI box to compensate for this, or you could probably just switch out a couple resistors on the Ultra preamp board to change the impedance. If your guitar has active electronics, then you may not have a problem.

As for the DSP aspect of things, you will need to get your RPi up and running and install the Jack Audio Connection Kit, and Either Guitarix or some other audio manipulation sofware. If you are using standard Raspbian, then just install guitarix with "sudo apt-get install guitarix"

There is a bit a of a learning curve for using all this, but what you want to do certainly can be done with some effort.