LinuxMusicians

I will be using AVLinux for a live software synth setup. I am trying to configure a Peavey USB-P USB DAC for output audio. Once connected up, I see it in alsamixer specified as USB Audio DAC, "lsusb" shows it as an Texas Instruments device, but I cannot get audio to play out through the DAC. It is selectble, but I just can't confirm whether it is really hooked up or not. I suspect my lack of knowledge on how to map audio ports in linux is the issue. Any assistance would be much appreciated.

Thank You

It is a class compliant device, according to https://peavey.com/products/index.cfm/item/875/117099/.

Try setting it as the jack output device in the qjackctl settings. Does that work?

What software are you using? You are talking about "a live software synth setup", what exactly do you mean? You say "It is selectable". In what application?

Problem is: does your software synth (a VST???) want to use Jack audio or ALSA? If you select your audio device in Qjackctl but your synth is configured to use ALSA then you hear nothing. Do you already know about Jack and ALSA? Because that's very confusing when you start using Linux and music production.

Good luck!

This appears to be a line level audio DAC
device has USB connection from PC, 2*XLR outputs & a mono/stereo switch
no hardware controls like some interfaces so level settings should be in alsamixer
'this unit complies with part 15 of the FCC rules' = class-compliant

if it is visible in ALSA, suggest trying 'speaker-test' or 'aplay' commands to check audio playback
(may need to set device profile to 'off' in Pulseaudio if it is installed)

maybe this is like some other devices that do not like 44100Hz sample rate and needs 48000Hz ?

Linuxmusician01 wrote:What software are you using? You are talking about "a live software synth setup", what exactly do you mean? You say "It is selectable". In what application?

Problem is: does your software synth (a VST???) want to use Jack audio or ALSA? If you select your audio device in Qjackctl but your synth is configured to use ALSA then you hear nothing. Do you already know about Jack and ALSA? Because that's very confusing when you start using Linux and music production.

Good luck!

I should have been more specific. I will be using Carla to host setbfree, Zynaddsub FX and samples. Selectable as in it shows up in Jack as an output device and in alsamixer. Yeah, the whole jack/ALSA is a bit confusing.

I think I have it working now. Levels are lower than I was expecting. After being sure the DAC was mounted correctly, I set it up in Jack as an output device and it is working. However, as I look at the audio on an oscilloscope it is REALLY noisy. I probably missed the audio previously because of the noise. I suspect a noisy USB port on the laptop I am using. Now I am looking into USB isolation devices. Suggestions??

milo wrote:It is a class compliant device, according to https://peavey.com/products/index.cfm/item/875/117099/.

Try setting it as the jack output device in the qjackctl settings. Does that work?

I think that worked. Audio is really noisy though.

nikgnomicradio wrote:This appears to be a line level audio DAC
device has USB connection from PC, 2*XLR outputs & a mono/stereo switch
no hardware controls like some interfaces so level settings should be in alsamixer
'this unit complies with part 15 of the FCC rules' = class-compliant

if it is visible in ALSA, suggest trying 'speaker-test' or 'aplay' commands to check audio playback
(may need to set device profile to 'off' in Pulseaudio if it is installed)

maybe this is like some other devices that do not like 44100Hz sample rate and needs 48000Hz ?

I have audio now. I did actually set jack up from it's normal 44.1khz to 48khz. Not sure if that made a difference, but the specs show 48khz for this device. I may experiment later to see if it functions at 44.1khz. I have yet to hear the audio as I am just confirming audio with an oscilloscope at this point.

Thanks all for help and suggestions. I have audio at this point. I have yet to confirm how it sounds as I am just confirming audio with a scope. It is definitely noisy due to noisy laptop USB ports I suspect. I am going to try some USB isolators to see if that can cure my problem. Open to suggestions on an isolator that is relatively inexpensive.....

Just noticed if I unplug the power supply from the laptop and run on battery all of the noise goes away and I have good clean audio. I Will research further.

I use three of these for our podcast. One with Pulseaudio and the other two with Jack. Never had an issue with them.

The output is on the low side. Nothing a preamp can't sort.

If you are looking for a cheap isolator do a search on Amazon for ADUM3160.

nae wrote:Just noticed if I unplug the power supply from the laptop and run on battery all of the noise goes away and I have good clean audio. I Will research further.

That speaks volumes, ha ha. Good 'ol interference from a wall outlet (50 Hz; or 60 Hz if you're an American). Anyway, I'm glad you've got it working. Thanks for the tip 'bout setBfree! What a great LV2 plugin man! Never knew it existed. I love Hammond organs!

VennStone wrote:I use three of these for our podcast. One with Pulseaudio and the other two with Jack. Never had an issue with them.

The output is on the low side. Nothing a preamp can't sort.

If you are looking for a cheap isolator do a search on Amazon for ADUM3160.

It is surprising to me that this is about the only product out there that is strictly a DAC and has balanced outputs. What a great idea.

Output does seem low. Hopefully sound board can gain it without too much noise

I'll check it out!

Thanks!

Linuxmusician01 wrote:

nae wrote:Just noticed if I unplug the power supply from the laptop and run on battery all of the noise goes away and I have good clean audio. I Will research further.

That speaks volumes, ha ha. Good 'ol interference from a wall outlet (50 Hz; or 60 Hz if you're an American). Anyway, I'm glad you've got it working. Thanks for the tip 'bout setBfree! What a great LV2 plugin man! Never knew it existed. I love Hammond organs!

SetBFree is pretty awesome. Love how it sounds!

nae wrote:

VennStone wrote:I use three of these for our podcast. One with Pulseaudio and the other two with Jack. Never had an issue with them.

The output is on the low side. Nothing a preamp can't sort.

If you are looking for a cheap isolator do a search on Amazon for ADUM3160.

It is surprising to me that this is about the only product out there that is strictly a DAC and has balanced outputs. What a great idea.

Output does seem low. Hopefully sound board can gain it without too much noise

I'll check it out!

Thanks!

Ha. I had already ordered one and that is the exact one that I ordered. Crossing fingers.

I actually swapped to another laptop power supply and there was a dramatic reduction of noise. Stupid laptop supplies. Still some room for improvement. I wonder about getting a 3rd party power supply for reducing noise even more....I may consider it if it will help.

The USB isolation is probably just a very good idea to keep ground loops at bay when interfacing to live event soundboards.

Update:

I used a ADUM3160 from amazon on the USB port and can report that it cleaned up the noise. Everything seems to be working.

So far, with a midi to USB device and headphone jack audio, latency hasn't been an issue. I am very hopeful that the USB-P doesn't introduce painful amounts of latency. I'll be putting it all into a sound board this week, so I'll know soon.