Audio Line-out

Everything relating to hacking, expanding and modifying the Joggler hardware.
EdT
Posts: 13
Joined: Fri Jul 06, 2012 9:25 am

Audio Line-out

Post by EdT » Fri Jul 06, 2012 2:46 pm

Trying to connect the headphone outputs to an amplifier gives absolutely awful sound quality.

It seems that the Joggler uses the STAC2902 as its DAC. This seems to have four Audio Ports - 2 for headphone and 2 for Line-Out.

Has anyone tried to connect a line out socket directly to Port B (pins 21 and 22) or Port C (pins 23 and 24) of the STAC2902 to give a Line-Out signal suitable for feeding into an amplifier?

Can anyone see any problems with such an idea? Would it require any changes in the Audio Config files? My Unix days were about 15 years ago, so a bit rusty.

Thanks

gegs
Posts: 1143
Joined: Fri Mar 04, 2011 3:22 pm
Location: Edinburgh

Re: Audio Line-out

Post by gegs » Fri Jul 06, 2012 4:36 pm

I'm using a Behringer UCA 202 USB DAC/soundcard. It has line out and optical S/PDIF and the sound is pretty good (to my ears at least). I don't know why anybody bothers with the headphone output when even a very cheap USB soundcard - http://amzn.to/LFAslY - gives much superior sound.

EdT
Posts: 13
Joined: Fri Jul 06, 2012 9:25 am

Re: Audio Line-out

Post by EdT » Fri Jul 06, 2012 5:05 pm

Thanks for the reply.

Any idea how good those USB sound cards are?

Even more to the point, looking at Amazon there seem to be several of them at pretty good prices - Would any of them work with the Joggler, or would they need new drivers? Would they need any changes in the config files?

Sorry there are so many questions, new to this side of things.

EdT
Posts: 13
Joined: Fri Jul 06, 2012 9:25 am

Re: Audio Line-out

Post by EdT » Fri Jul 06, 2012 5:10 pm

Sorry, just noticed something else. I was hoping to wire this into the Aux input on my amplifier - since all other sound goes that way.

I presume that with one of those USB sound cards, I'd still have a problem with levels between the card and the amp?

gegs
Posts: 1143
Joined: Fri Mar 04, 2011 3:22 pm
Location: Edinburgh

Re: Audio Line-out

Post by gegs » Fri Jul 06, 2012 5:18 pm

EdT wrote:...Would any of them work with the Joggler, or would they need new drivers? Would they need any changes in the config files?....
The cards I've mentioned work out of the box, if you apply the USB soundcard switch on PnPIII or Squeezeplay OS. I mention how to do that on the following thread - http://www.jogglerwiki.com/forum/viewto ... swf#p11164

Just buy a cheap card and try it, you'll be amazed at the increase in output volume and quality. If you want phono or S/PDIF optical connections, buy the Behringer UCA 202.

EdT
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Joined: Fri Jul 06, 2012 9:25 am

Re: Audio Line-out

Post by EdT » Fri Jul 06, 2012 5:43 pm

Thanks for the info.

I'm pretty much set on a phono output so I'll probably go with the Behringer UCA 202.

Last question (I hope) I'm still running on the original OS (I presume, it shows the O2 logo at startup). Any idea how to get the UCA 202 recognised on that?

gegs
Posts: 1143
Joined: Fri Mar 04, 2011 3:22 pm
Location: Edinburgh

Re: Audio Line-out

Post by gegs » Fri Jul 06, 2012 8:39 pm

Mine shows the O2 logo but it's been pimped with PnPIII. I strongly suggest you do the same. If you don't, you'll need to SSH a modified asound.conf file to /etc

Search for 'asound.conf' on the forum for the file contents (create it in Notepad).

EdT
Posts: 13
Joined: Fri Jul 06, 2012 9:25 am

Re: Audio Line-out

Post by EdT » Sat Jul 07, 2012 2:08 pm

Thanks a lot for the info.

I've gone down your suggested route and put PNPIII on it. Just waiting for the sound card now.

papaiannis
Posts: 63
Joined: Tue May 15, 2012 9:53 pm

Re: Audio Line-out

Post by papaiannis » Wed Jul 11, 2012 10:04 pm

If you want hi-end audio, go for the spdif mod (see on the wiki http://www.jogglerwiki.com/wiki/Internal_SPDIF_output).
You have to solder a few electronic components, though (two resistors and two capacitors).
It's worth the effort.

Alekos

EdT
Posts: 13
Joined: Fri Jul 06, 2012 9:25 am

Re: Audio Line-out

Post by EdT » Thu Jul 12, 2012 8:35 am

Ah, but then I'd have to have an amp with SPDIF input.

I'm just after something which is better that the internal sound card, but no better than my old lo-fi ears can notice.

papaiannis
Posts: 63
Joined: Tue May 15, 2012 9:53 pm

Re: Audio Line-out

Post by papaiannis » Thu Jul 12, 2012 1:08 pm

Buy a DAC with spdif input, rather than a USB sound card. You can find very decent DACs on ebay at the same price of a sound card.
The result will better. Unless you use an extra-quality pc (low jitter, low noise, high price).
Have fun.

Alekos

gegs
Posts: 1143
Joined: Fri Mar 04, 2011 3:22 pm
Location: Edinburgh

Re: Audio Line-out

Post by gegs » Thu Jul 12, 2012 4:50 pm

While I agree with your opinion regarding quality, not everyone would be comfortable with opening their Joggler and soldering components onto the mainboard. If you are not a high end audiophile you will be perfectly happy with the Behringer UCA 202. It is brilliant for the price, has low noise and I wouldn't know what jitter sounds like anyway.

The difference between the internal card and the Behringer is vast but I suspect the difference between the Behringer and a DAC with S/PDIF input is a rather smaller quality gap. Not one I'd risk trashing my Joggler for anyway.

EdT
Posts: 13
Joined: Fri Jul 06, 2012 9:25 am

Re: Audio Line-out

Post by EdT » Thu Jul 12, 2012 9:29 pm

OK, the sound card arrived, I've plugged it in ... nothing!

I've been into the Squeezeplayer settings and set it to use the external USB sound and restarted it all ... still nothing.

What have I missed? (This is the PNPIII version here).

p.s. By the way, thanks for all the help.

EdT
Posts: 13
Joined: Fri Jul 06, 2012 9:25 am

Re: Audio Line-out

Post by EdT » Thu Jul 12, 2012 9:53 pm

OK, I've found it. Needed to run the script in the flash apps.

Thanks for all the help along the way.

gegs
Posts: 1143
Joined: Fri Mar 04, 2011 3:22 pm
Location: Edinburgh

Re: Audio Line-out

Post by gegs » Fri Jul 13, 2012 12:26 am

EdT wrote:OK, I've found it. Needed to run the script in the flash apps.

Thanks for all the help along the way.
What did you think of the USB sound card? How much has it improved the audio from your Joggler? I think mine are a vast improvement, even the cheap sound card on my kitchen Joggler, but it would be good to hear what others think.

ilovemyjoggler
Posts: 706
Joined: Sun May 13, 2012 4:42 pm

Re: Audio Line-out

Post by ilovemyjoggler » Fri Jul 13, 2012 4:47 am

gegs wrote:What did you think of the USB sound card? How much has it improved the audio from your Joggler? I think mine are a vast improvement, even the cheap sound card on my kitchen Joggler, but it would be good to hear what others think.
I bought one of the cheapest usb soundcards I could find and it definitely works for me. My speakers are also cheap so can't quite manage all the extra va va voom so can't have it too loud as the sound distorts, but it gives me all i need in the kitchen. Simple and cheap solution. Brilliant. Cheers.

EdT
Posts: 13
Joined: Fri Jul 06, 2012 9:25 am

Re: Audio Line-out

Post by EdT » Fri Jul 13, 2012 8:22 am

gegs wrote:What did you think of the USB sound card? How much has it improved the audio from your Joggler? I think mine are a vast improvement, even the cheap sound card on my kitchen Joggler, but it would be good to hear what others think.
It's already a great improvement on what it was.

I've still got it feeding into the phono sockets usually meant for a turntable on the amp (has a preamp), so the signal level is still too high. This weekend I'll rearrange it so it feeds into the tuner or aux sockets.

EdT
Posts: 13
Joined: Fri Jul 06, 2012 9:25 am

Re: Audio Line-out

Post by EdT » Fri Jul 13, 2012 8:30 am

gegs wrote: The difference between the internal card and the Behringer is vast but I suspect the difference between the Behringer and a DAC with S/PDIF input is a rather smaller quality gap. Not one I'd risk trashing my Joggler for anyway.
If anyone's amp has a SPDIF optical connector, the Behringer would connect to that and so still give the benefits of a better DAC without having to take the risk of opening up the joggler.

gegs
Posts: 1143
Joined: Fri Mar 04, 2011 3:22 pm
Location: Edinburgh

Re: Audio Line-out

Post by gegs » Fri Jul 13, 2012 2:31 pm

Thanks EdT, that's what I meant about the Behringer. The quality is very good for my hi-fi setup and it has optical S/PDIF, stereo phono and headphone outputs. The quality difference between straight S/PDIF output (as outlined in the mod mentioned earlier in the thread) and USB conversion to S/PDIF is probably measurably real, but not of sufficient audible difference to justify opening my Joggler. I don't think my amp and speakers are of sufficient quality to reap the rewards anyway.

jkn
Posts: 105
Joined: Sat Jul 16, 2011 11:18 am

Re: Audio Line-out

Post by jkn » Fri Jul 13, 2012 2:34 pm

EdT wrote:
gegs wrote:What did you think of the USB sound card? How much has it improved the audio from your Joggler? I think mine are a vast improvement, even the cheap sound card on my kitchen Joggler, but it would be good to hear what others think.
It's already a great improvement on what it was.

I've still got it feeding into the phono sockets usually meant for a turntable on the amp (has a preamp), so the signal level is still too high. This weekend I'll rearrange it so it feeds into the tuner or aux sockets.
Feeding it into the phono input will screw up the frequency response FYI; the 'turntable preamp' part of the amp applies an ('RIAA') correction for the non-linear response of the cartridge. Applying that to the output of the Joggler will (...tries to remember...) mean that you get an awful lot of bass, and an awful lot less treble, than you should be doing.

Things will sound a lot nicer into the tuner or aux sockets.

HTH, Jon N

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