No guitar input to Scarlett 2i2

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donnek
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No guitar input to Scarlett 2i2

Post by donnek »

I'm trying to set up a 2nd-gen Focusrite Scarlett 2i2 to input guitar into a laptop. I'm using Ubuntu 20.04 with a low-latency kernel, and jackd2 (1.9.12~dfsg-2ubuntu2). I have JACK running OK (eg I can get sounds out of amsynth and AMS).
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I can plug in the Scarlett and, after changing the input/output, have the sound from the laptop go out to the headphone socket of the Scarlett (so it's plainly working at some level).
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I can get sounds from ToneLib GFX (using VMPK to trigger a sound on amsynth, and feeding that to ToneLib, where I can hear the amp effects added).

BUT ... I can't seem to get the last part of the jigsaw - namely, plugging in a guitar, and having it routed through ToneLib. In Catia ToneLib appears as JUCEJack, and seems to be connected properly, but I get no sound.
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I've tried adjusting the Audio settings in ToneLib, to no effect. With the JACK settings I can get the Test output tone. The options for both input and output are system, PulseAudioJACK Sink, a2j, and none. Changing these seems to have no effect. (I'd show an image, but I think I'm limited to 3).

If I change Technology to ALSA instead of JACK, I get a shedload of options for output, including a number of Scarlett options, and also a (shorter) set of options for input, but strangely, these all seem to relate to output too. Fiddling about with these also seems to have no effect.

I feel like I just need to change some setting somewhere to get it working, but I can't figure out where. :-( Any suggestions would be welcome.

By the way, purely for interest, I've also enabled the driver for Geoffrey Bennett's additional Scarlett controls (viewtopic.php?f=6&t=24763)
as described by unfa (https://www.youtube.com/watch?v=5zFA5piXf8Q&t=50s), but 2nd gen Scarlett 2i2s have no additional controls beyond those on the case.
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sysrqer
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Re: No guitar input to Scarlett 2i2

Post by sysrqer »

I presume you are getting the input light on the Scarlett when you play?
Have you looked at alsamixer (you might need to choose the right card in there)? It might just be muted. I have a vague recollection of this being a default and being a very typical issue.
donnek
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Re: No guitar input to Scarlett 2i2

Post by donnek »

No lights at all, except the green USB light and the red 48V light when I switch it on. The Gain control knob lights flash when I put the guitar jack in, but that's it.

Muting sounds like a likely cause, but alsamixer shows no controls for the Scarlett when I select it with F6, and (bizarrely) pressing any other F key quits alsamixer ...

I've come across a few threads (like https://forums.linuxmint.com/viewtopic. ... 9&t=277259) where it seems the 2nd-gen Scarlett has to be initialised in a Windows box (last post).
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sysrqer
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Re: No guitar input to Scarlett 2i2

Post by sysrqer »

That's strange, I think the input light should be showing a signal regardless of what is happening inside the computer.

If it's not showing any controls in alsamixer then I can only imagine that you haven't set the options, or it has not been done correctly. What does this show?

Code: Select all

dmesg | grep -i -A 5 -B 5 scarlett 
You shouldn't need to initialise it on windows.
donnek
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Re: No guitar input to Scarlett 2i2

Post by donnek »

Code: Select all

[ 8506.360241] usb 2-1: new high-speed USB device number 9 using xhci_hcd
[ 8506.486678] usb 2-1: New USB device found, idVendor=1235, idProduct=8202, bcdDevice= 4.1b
[ 8506.486691] usb 2-1: New USB device strings: Mfr=1, Product=3, SerialNumber=0
[ 8506.486696] usb 2-1: Product: Scarlett 2i2 USB
[ 8506.486700] usb 2-1: Manufacturer: Focusrite
I don't think the 2nd-gen 2i2 has any options to set - that's why it doesn't appear on the list on that page.
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sysrqer
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Re: No guitar input to Scarlett 2i2

Post by sysrqer »

Ah yeah I see, sorry. It seems like everything is working then but it's weird that you are not getting any signal showing on the input light. Have you tried another cable or a different source? How about not having the cable plugged into the guitar and just touching the end, you should see the light flash on and off.
donnek
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Re: No guitar input to Scarlett 2i2

Post by donnek »

I've tried different cables. When inserting the plug into the guitar I do get a buzz if I touch it to the side of the socket, but no lights. :-(
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sysrqer
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Re: No guitar input to Scarlett 2i2

Post by sysrqer »

That is odd. Short of it being defective, I'm not sure what else to suggest. Maybe someone else with one can help as I upgraded to the 6i6 but I don't remember having to do anything with the 2i2 for it to work.

Do you have it plugged into a usb hub or anything like that? I wonder if it's not getting enough power.
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Loki Harfagr
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Re: No guitar input to Scarlett 2i2

Post by Loki Harfagr »

In that kind of wotisaidwot I'd try to proof the input scheme and test the same entry using a line level something (radio, CD, Epianodemoplayer, tetriskey, anythingvolted) instead of the guitar, if you get some (earable and led-seeable) signal you(re just dealing with some impedance or entry level, thus try the guitar thru a DIbox or a preamp or anything linelevelledonOUT (bigmuff, rat, wah) and do something with the input gain pad and pots, see what changes what. (and since you told about some 48V which usually linked to phantom powering, do not use that with a guitar, AAMOF use that only when you know what and you have the acoustic mike that actually requires it)
donnek
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Re: No guitar input to Scarlett 2i2

Post by donnek »

Ah, thanks both. Progress. If I wire the headphone out of a CD player to the input jack on the Scarlett I get a flashing/solid green light around the gain control, and I can hear the output fine.

So does this mean the USB port on the laptop isn't fully powered (as sysrqer wondered), and I should therefore get a powered USB hub?

Or does it mean I need to get a DI box (as Loki Harfagr suggested)? I don't have any of the other equipment you mentioned, Loki, and I was thinking of this DI box: https://www.gear4music.com/PA-DJ-and-Li ... DI-Box/297
donnek
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Re: No guitar input to Scarlett 2i2

Post by donnek »

Also, Loki, thanks for the info on the 48V.
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