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

[struth]

possibly the router. i had one of those sky jobs and it was a pain. rarely got any networking with it. probably the set up could be changed but i just gave up trying.

[WAD62]

possibly the router. i had one of those sky jobs and it was a pain. rarely got any networking with it. probably the set up could be changed but i just gave up trying.

Cheers for the reply...

Router is fine (and has been for years), LMS & 4 SBs hanging off it, SKY HD, numerous laptops, and plenty of other mobile devices, I even used the Edimax WiFi dongle with my laptop, superb connectivity...I suspect some incompatibility between the dongle and the Pi, there're lots of conflicting reviews on amazon R.E. Pi wifi dongles, and it's hard to track one that will definitely work with a Pi 2

Perhaps this should be a separate thread...

[User211]

Anyone tried using a PI 2 with an A2DP dongle and streaming from a Bluetooth laptop? Idea is to get it to do A2DP to async USB out to an external DAC.

Sounds like a challenge but it would be very cool. Specifically want async USB out and no other type.

BTW there are plenty of Bluetooth receivers that will receive A2DP and output SPDIF but NONE that will do async USB. Might need some code to get this to work if there is nothing out there that will do it. Suspect there is nothing.

[Gordon@IQ]

Hi, I've just recently jointed AoS as a customer had provided me with a link to this discussion. What a surprise to see so many positive comments on this thread, a load of questions and obvious thirst for great SQ.

Firstly, I have signed up as a vendor so obviously I have an overall goal to increase business but I hope you will also see that I am just as interested in musical enjoyment and SQ. I will answer any questions I can and will try to present an unbiased view. I've read through the 50 pages or so and put the following together - please let me know if I missed something.

Q) Does Marco have shares
A) No

Q) Do you have any spare Pi-DAC+ lying around
A) No

Q) When will you have Pi-DAC+
A) blank PCBs will arrive 20th April, these will then need to be populated and tested before being made available for customers to purchase. I expect them to be available late April.

Q) Where can I buy Pi-DAC+
A) https://www.tindie.com/stores/IQaudio/ but we'll also be adding UK distributors (a couple well known in the Pi world) end April too.

Q) What ppower supply do you recommend?
A) The Apple USB bricks are pretty good, for the Pi-AMP+ (which back powers the Pi and DAC+ too) we recommend the XP Power VEH60US15

Q) What about Linear power supplies?
A) YMMV - many have got this going and say they can hear a difference. The Pi-DAC+ pin usage is shown in the user docs but don't go blowing up your DAC+ doign this - we recommend the DAC+ is powered from the Pi or the Pi-AMP+ :-)


Q) Why is everything on tindie.com in US$
A) That's a tindie thing, We use tindie as it is a great sales location for the DIY / Maker market. We're based in the UK and Pi-DAC+ etc. are manufactured here too. I'm not a web page specialist so haven't put the effort or time into doing our own shop front. This may come but I'd rather use distributors to handle that going forward.

Q) Hardware volume control
A) Right, that's a good topic and I'll try and address it simply.
Some DAC chips output at a specific fixed line level (TI PCM5102 plus many more), others have variable output, the TI PCM5122 as used on Pi-DAC+, for example. The variable output is controlled on-chip through a volume register. Write value "a" into the volume register and you get max volume "A", value "b" and you get volume "B". How this volume change is handled on-chip is deep in the device design. This volume is delivered to the Linux system through the Linux ALSA driver and the Linux ALSA utilities (alsamixer for example) will either pass this variable volume to the DAC or will emulate the volume adjustment by removing bits from the data BEFORE it gets to the DAC. For best SQ you want ONE volume control over the whole system (IMHO) and you don't want to start removing bits of real data to emulate low to high volume - you're throwign away data before it gets converted.

This is why we suggest that HW volume control is better than "emulated" software volume control.

The PCM5122 device however has three volume controls (two are a gain rather then volume control as such). In the original driver the full range of the PCM5122 was exposed - yep -103.5db to +23db. This didn't feel right and it was very simple to start clipping everything. I changed the driver to limit the volume from -103.5db (0%) to +4db (100%) - this allowed for quiet recordings to be played louder but still risked clipping.

As this is Linux and almost anyone can change drivers etc. there was a change made to the underlying driver which removed the single volume control and exposed 3 which worked in combination. This was exposed at the same time as the release of the Raspberry Pi2 and frankly took many by surprise.

At that point in time we had three voluem controls (mixers):
- PCM (0..100%) this is the variable bit
- Playback (selected max 1vrms or added a +6db gain for 2vrms output) should be set ON
- Playback boost (added a 0.8db gain) should be set ON

So by adjusting the mixer "PCM" you still got the -103.5db to +4db volume range

Again as this is Linux it's a work in progress and the change was impacted by another piece of code and at startup on the Pi there is a bit of code which looks for a mixer called "playback" and sets t to -23db (or something) - the impact of this is to set the max output from the DAC to just over 1v rather than just over 2v. If you are experiencing low output volume then check your settings.

A recent change has been made to this driver to attempt to add some sanity to all this. So the mixers "Playback" have been changed to "Analog Playback Volume" as they are actually analog gain setting) and "PCM" has been changed to "Playback Digital Volume". At the same time the max volume range has changed so that 100% is now 0db.

If you are interested then read here: https://github.com/raspberrypi/linux...decs/pcm512x.c

This change will ripple through to the Raspberry Pi Raspbian release in the coming days and unless you update your OS you will not notice. The Pi Linux software guys (those who have delivered Volumio / Rune Audio / PiCorePlayer / PiMusicBox / Moode / Shair-port sync etc.) all knwo about these things and when they update their software should make sure these changes are taken into account.



Q) Why does the Volumio volume appear onto work between 70 and 100%?
A) This is a long standing issue between ALSA (the underlying linux audio system) and MPD (the media player as used by Volumio etc.) One (I believe) uses a linear representation and the other a logarithmic range for volume. Is there a fix - not yet other than: living with this, use software volume control, use a physical volume knob or Remote control.

Q) How do I add a physical volume knob?
A) You want to add a rotary encoder to the Pi's GPIO pins and have some software that takes the rotary encoder's pulses and translates them to ALSA calls under the hood to adjust the Pi-DAC+ volume. Some details are in the IQaudIO user docs. The software for the Rotary Encoder (and for the IR code - but it's out of date) is here: www.github.com/iqaudio/

Q) This is all beyond me - do you have anything which works out the box?
A) I'm trying - there are a number of pre-configured Pi SD card images on www.iqaudio.com/downloads/ (The docs are here too) but I am a little stretched to keep these all up to date - I do refresh them from time to time based on customer needs.

Q) Anyone tried using a PI 2 with an A2DP dongle and streaming from a Bluetooth laptop?
A) This is possible and there are a few walk throughs on the web. However if you expect zero latency walk away.

Q) What's next?
A) Well we have a 2x20w Class D amp (Pi-AMP+) which sits on top of the Pi-DAC+ and sounds great :-)

Q) After that?
A) New Pi-DAC+ end of April, a BeagleBoneBlack version of the Pi-DAC+


Sorry for the loooonnnnnnggggg post - I really hope that helps to answer the various questions and more. If there are others please PM me here or email me directly on gordon@iqaudio.com

BR,

Gordon

[struth]

[Krisbee]

Anyone had any success getting WiFi connectivity with the Pi 2?

I'm using the Pi2, Squeezeplug/Max2play NOOB distro, IQaudio Pi-DAC+...and this wiFi dongle...

http://www.amazon.co.uk/Edimax-EW-78...=cm_cr_pr_pb_t

...via LAN LMS sees the player, however wifi connectivity to my SKY sagem router is unworkable...

Your wifi dongle appears to have been used successfully at least with the original Pis ( see here: https://sites.google.com/site/picore.../wifi-dongles?) Perhaps it's just a software config problem. Did you attempt wifi setup via the Squeezeplug/Max2play web interface, or at the command line?

[Krisbee]

Sorry for the loooonnnnnnggggg post - I really hope that helps to answer the various questions and more. If there are others please PM me here or email me directly on gordon@iqaudio.com

BR,

Gordon

Thanks for all the technical detail. You say a new Pi-DAC+ end of April, so you have made what changes to the next batch?

[WAD62]

Your wifi dongle appears to have been used successfully at least with the original Pis ( see here: https://sites.google.com/site/picore.../wifi-dongles?) Perhaps it's just a software config problem. Did you attempt wifi setup via the Squeezeplug/Max2play web interface, or at the command line?

Hence me buying it, however check out the first answer in the Q&A section...

http://www.amazon.co.uk/Edimax-EW-78...eywords=edimax

I did the NOOB LAN setup, then the same for the WiFi connection, I've posted a question for the Max2play chaps on the slimdevices forum...

http://forums.slimdevices.com/showth...l=1#post814146

[walpurgis]

I almost understand none of your post Gordon.

[Krisbee]

Hence me buying it, however check out the first answer in the Q&A section...

http://www.amazon.co.uk/Edimax-EW-78...eywords=edimax

I did the NOOB LAN setup, then the same for the WiFi connection, I've posted a question for the Max2play chaps on the slimdevices forum...

http://forums.slimdevices.com/showth...l=1#post814146

Ah, sounds like it's recognising WIFI networks but not connecting properly. Dongle makers have a nasty habit of changing chipsets between different hardware versions of the same product. Does using "lsusb -v" at the command line give any clue what chipset your dongle actually has, and what driver is being loaded? The command "lsmod | grep 81*" should give the answer the second question. You say you have a .tz driver, what exaclty is that file and where was that taken from?

If you only want to use Squeezelite player, do you have particular reason not to use the picoreplayer?