'Analog Dinosaur' succumbs to the joys of FBA : enter Raspberry Pi 2/IQ-Audio DAC+!!

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Originally Posted by r100

:scratch:

Thank's for trying ! I unfortunately don't have the same DAC you have so I cannot test it here. Maybe a kind AoS member who has the same DAC as you have could explain why it doesn't work with those settings.

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No problem, Roops. It's not a big deal, as I'm getting a superb sound the way I'm using things, but hopefully I'll get to the bottom of the issue after speaking with a friend tomorrow, who has a similar set-up to me with the Pi :)

Marco.

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Originally Posted by Marco

Hi Marc,

Is that post directed at me? If so, I'm sorry, but I really understand any of it. For example, what is PCM and how do you set it to 86%? And what is Playback boost and how do you adjust that? :confused:

A simple step-by-step guide, in layman's terms would be good.

Marco.

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Sorry Marco, yes but I suspect I might have either misunderstood which dac you have? I couldn't see a 'hardware control' (as in an actual physical knob) on the Pidac but the manual (P19 linked previously) shows that there are 3 gain controls available for the hardware in ALSAMixer (how to access and adjust this is described in the manual) one of these (playback) equates to a 'hardware' volume control because it's adjusting the voltage gain of the converter (rather than adding of removing bits):

PCM (which is the playback volume of the software in to the interface) and

'Playback' which appears to adjust the actual voltage gain coming out of the converter (so is useful for gainstaging the input of the next item in the chain)

Given that folk are concerned about 'losing bits' by using digital volume controls the settings I've advocated seek to ensure there is no digital gain or attenuation being applied and to simply use the 'playback' control to adjust the analogue gainstaging so the output of the pi can be appropriately set for the input of the pre/power amp it's connected to.

Hope this helps.

To quote Gordon @iqaudio

"The PCM5122 (as used on the Pi-DAC) can go from -103.5db to 23db. We have limited it to +4db at 100% on Alsa but not sure what other cards will do here - that all makes it very difficult for apps like RuneAudio. "

Therefore I set mine at 95 to stop any digital distortion (clipping) from tracks that are recorded hot, what with loudness wars.

Was that done with mine too, Duncan?

Marco.

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Originally Posted by Rothchild

Sorry Marco, yes but I suspect I might have either misunderstood which dac you have? I couldn't see a 'hardware control' (as in an actual physical knob) on the Pidac but the manual (P19 linked previously) shows that there are 3 gain controls available for the hardware in ALSAMixer (how to access and adjust this is described in the manual) one of these (playback) equates to a 'hardware' volume control because it's adjusting the voltage gain of the converter (rather than adding of removing bits):

PCM (which is the playback volume of the software in to the interface) and

'Playback' which appears to adjust the actual voltage gain coming out of the converter (so is useful for gainstaging the input of the next item in the chain)

Given that folk are concerned about 'losing bits' by using digital volume controls the settings I've advocated seek to ensure there is no digital gain or attenuation being applied and to simply use the 'playback' control to adjust the analogue gainstaging so the output of the pi can be appropriately set for the input of the pre/power amp it's connected to.

Hope this helps.

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Hi Marc,

I understand a little better where you're coming from now, but wouldn't have a clue how to make any adjustments [what is ALSAMixer?] as they all seem to be software related and beyond my comprehension of computer language. Thanks, though :)

Marco.

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Originally Posted by WAD62

If you're talking about the IQaudio Pi-DAC+ board there are some re-manufactured boards available, and only black cases (matte or gloss), mine arrived yesterday, drop them an email;

...just waiting for an HDMI to DVI adapter before I boot it up, I'm using the Squeezeplug NOOB software, but I'll still probably need a monitor for initial configuration...should be interesting :)

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That's brilliant, thanks for that Will. I sent them an Email having read your comment and they got back to me within the hour to say that not only did they have a couple of the remanufactured boards left, but also that they're based just down the road from me, so I could go and pick one up! How's that for a result?

Well, that's my weekend sorted ;-).

Nice one, Rich. That *is* a result! Let us know how you get on :)

Marco.

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Originally Posted by Marco

, but wouldn't have a clue how to make any adjustments [what is ALSAMixer?]
Marco.

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That's why I linked the manual, it's all explained in plain terms there for you ;-)

For those with better maths than me there's a useful page about gain structure and reference levels here: http://www.sengpielaudio.com/calculator-db-volt.htm which can help get you to some sensible starting points so that you can then home in with your ears on the sweet spot.

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Originally Posted by Marco

No problem, Roops. It's not a big deal, as I'm getting a superb sound the way I'm using things, but hopefully I'll get to the bottom of the issue after speaking with a friend tomorrow, who has a similar set-up to me with the Pi :)

Marco.

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:)

I think there is some confusion about the "hardware" word in the documentation. As far as I can see, it means there is a dedicated 32 bit chip on the IQ DAC doing volume attenuation in the digital domain. So, the "hardware" seems to refer to that chip.

But all this is irrelevant really as long as the SQ is satisfying. And I am sure you have plenty of reference points to know it is.

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Originally Posted by lovejoy

That's brilliant, thanks for that Will. I sent them an Email having read your comment and they got back to me within the hour to say that not only did they have a couple of the remanufactured boards left, but also that they're based just down the road from me, so I could go and pick one up! How's that for a result?

Well, that's my weekend sorted ;-).

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Top stuff Rich!

I can thoroughly recommend the IQ case, very well designed, and looks the business, my earlier photo doesn't do it justice :)

Mind you give the build instructions a read first...http://www.iqaudio.com/downloads/IQaudIO.pdf

It'll save time in the end, it's a question of getting the right spacers onto the main Pi board first time...

Top tip! One side of the case panels is protected by sticky back plastic...and is not 'unprinted' as some idiot might complain...err sorry about that Gordon ;)

Apparently it's a common mistake...I think he was just being polite

P.S. I'm still waiting my HDMI to DVI adaptor to arrive (hopefully today) before I light the blue touch paper...:eyebrows: