Puppy Linux Discussion Forum

[wlowes]

Ildose
Thank you for the command to validate nrpacks. Glad to discover that it holds across reboots. I thought so based on sound quality, but had no way to validate.

Douwe,
Glad to hear you are getting such good sound on the atom. It will be interesting to see if Ryeland has same experience. If one of you gets the chance, it would be interesting to swap the caps on your ALIX, and see how it then compares to the Atom. I found quite a pop up in quality by replacing electrolitics with organic polymer. The Blackgate is likely not hurting either. In total, for less than $10 investment in caps it is a pretty good performance. These caps fully develop over 200+hours, so it will likely continue for a few days. It will never do HD resampling though.
Walter

[wlowes]

BTW
Code:
cat /sys/module/snd_usb_audio/parameters/nrpacks

Works perfectly. After power off/reboot. Entered command and it returns
20

short an sweet. Thanks

[PET-240]

What caps are you using exactly please wlowes?
Perhaps a photo?

Thanks,

Drew.

[i2k]

@Idolse : My primary reason to get the Alix board is because it will be easier to implement a linear power supply due to its' significantly lower power consumption. And my fanless Atom board is warm even though I already disable the CPU hyperthreading from the BIOS. I found used Alix 3d2 complete with enclosure, CF card, wifi adapter & powersupply for about 100$.

Is there any way to know the actual bitrate of the output ? I read on diyaudio that on other Puppy implementation a hi-res file will be downsampled to 16 bit on the output.

Have somebody tried to install a wifi USB adapter on mpdpup machine ?

Thanks in advance.

[ldolse]

Understood about the Alix, it's a good board, so by all means go for it.

[PET-240]

I need more play time dagnabbit!

Feeling a little left out not getting to play with and enjoy this puppy but hearing you guys talk about changes is a bit frustrating!

Thanks for all the assistance Idolse, really very cool!

[wlowes]

PET-240 I removed the stock electrolytics (35v 220u) and replaced them with Nichicon LF Organic Polymers 16V 270u. These are bypassed with BlackGate PK 50v .22u. Also have a BG F 100u 50v across the power input pins.

There is a lot of punch. Bass is deeper and cleaner.

I suspect the organic polymers provide most of the benefit, and are easy to find(mouser&future). Let the Alix run 7/24 for a couple of days to allow them to settle. I'll post pics later

[i2k]

@idolse : thanks for the confirmation that mpdpup is bitperfect, I can sleep well now.

@Douwe : I use similar setup as yours (Atom + picopsu). Currently the picopsu connects to an external 12v SMPS. Would you mind to share the schematic of your linear PSU ?
And do you think that Atom is sounds better than Alix ? I'm about to grab an Alix board so I need to know if it is necessary or not (providing that Atom sounds better).

@Wave IO users : how do you use this board : i2s or spdif output ? external or USB power supply ?

[PET-240]

I currently use the Wave with SPDIF for testing, USB input the Alix see's it straight up, if using the isolated I2S outputs it requires 3.3 or 5v to the chip. Using SPDIF, sounds really quite good, sorting a few tuning things, have a linear supply coming, will be running the Wave off a salas BIB shunt reg off that linear supply.
Linux sees the XMOS chip with the UAC2 driver in the kernel. Windows requires the thesycon driver supplied as a download. Figure if you are here you are using Mpdpup!

[Douwe01nl]

Hi all, a few updates.

SoX
Idolse and tempestuous, your directions about implementing Sox are great, it was very easy to get it working! SQ is better than libsamplerate (not big difference, may be wishful hearing). sampling now is up to 176400 KHz / 32bit. Tempestuous i agree 176.400 sounds better than 192000 (when playing 44.100 files), i experimented a lot in a former cMP2-setup.

nrpacks=100
Idolse, thanks for considering a kernel-change on this for a future release of mpdpup, i'm looking forward to it (please let me know when my limited knowledge of linux could be of any help).

Alix
Walter, i will use the alix in another room now. Because i removed the sound chip, i had to order a (cheap from Honkong) usb-soundcard i'll have to wait. When i have time (could take a while) i'll try the caps change and report.
Sound of Atom in my setup is better than Alix, although Alix could have great potential. If i studied the schematics of Alix well, Alix has switching voltage regulators. If one could disable/bypass them with lowdrop regs, this may boost SQ.

Atom
I2k, sound depends a lot on what kind of Atom board you have. My Asrock AD525PV3 has a few advantages:
- no needles stuff (like hdmi, pci-e, extra IDE-chips, usb3)
- good power management (no multiple power stages to cpu, 6 chokes on the board which is a lot for atom-boards)
- fanless (i removed the fan and extended the heat sink)
- memory latency adjustable in bios (i have now quiet "sharp" settings which require a startup "protocol": startup, wait 30 sec, pull power plug, put power plug in again, startup again, wait 50 sec, enjoy)
- memory management adjustable in bios (this is a very rare feature called rComp, better SQ if disabled)
And a few disadvanteges:
- cpu runs @1.8 GHz, can only be reduced in bios to 1.5G at cost of LAN functionality, so it runs rather hot. It is still in experimental stage (no enclosure). in future i'll need to connect enclosure and heat sink.
Again: i think it depends a lot on what Atom board you purchase.
Iirc Ryelands has FitPC, i hope he'll give mpdpup a try and report here.
The Asrock is driven by an old (80's) Philips linear lab-psu combined with pico-psu.

WaveIO
i use the isolated spdif output. The modded Benchmark DAC1 doesnt have i2s connector, so it needs a new mod before i can implement i2s.
Does it need 5v only for isolated spdif output? If yes, it would mean that if i use i2s or non-isolated spdif i could use 3.3v LifePo4 batteries?

[i2k]

@Douwe,
My Atom board is Intel D410 which is very very basic (single core, no hdmi, usb3, etc), most of unnecessary devices has been disabled from the BIOS.
I don't know about the power management as I only find 2 or 3 chokes on the board. But I'm curious how do you extend the heatshink ?

I'll get the used Alix board anyway, I can always re-use the Atom board to make a NAS box.

[Douwe01nl]

i2k, extending the heat sink was a really complicated process, which reaches far beyond rocket science. I just put a bigger heat sink up side down on top of the mounted heat sink cpu-temp around 50 degrees celcius.
When i make an enclosure later, i'll connect it to the enclosure with metal tape or something like that.

[PET-240]

Douwe,

The isolated i2s on the wave can be supplied with either 3.3 or 5v, it is dependent upon what voltage your dac supports for i2s. I would recall that Lucian advises not using the unisolated SPDIF as it is untested.
I will look into the reg requirements for the Alix and perhaps play with dedicated regs.
I have read reports that the isolated i2s sounds better. I wonder if this is a transmission line thing and the unisolated i2s is ringing?
Look forward to a few photos of your setup!
When I get Dropbox to start ill share a link to mine!

[PET-240]

How rough is this.......

http://db.tt/DGlGvBPI
http://db.tt/7WSydNoD

Stop laughing already, I happen to like apple boxes for their vibration damping.......

Cheers

Drew.

[audiosm]

I am reading with interest the discussions of mpd tweaks and differences in main PC .
My system mpdpup (only running for a few weeks) is an old Del laptop - AMB Labs Y2 dac with hardware re sampling to 24 bit 96khz externally powered, Preamp, and Linkwitz Pluto speakers - all DIY as much as possible .

This has replaced a windows system and I feel sure that puppy is making all sound better, it seems to have more musicality ? , when I first got it going it was a 4 hour session of all sorts of music with seemingly more depth and just better .
So now where to go with the next step in quality , some questions arise

1) Is it a BAD thing to have the music and Dac both on USB , it seems the best method is to have music coming from a network NAS drive .

2) is it better to have a dedicated low power PC ( my old DEL is only for the MPDPUP )

3) re sampling question , I downloaded some high re files , and find they play on my DAC using USB input that is limited to standard CD resolution due to PCM2707 used as a USB to Spdif converter , the dac supports all rates , but not from from its USB .
Does this mean mpd is down sampling to the USB input rate , even though I added a line in the mpdconf to say no resamples?

mixer_type "none"
mixer_device "disabled"
auto_resample "no"
auto_format "no"

I am confused as to what is going on here , is it still bit perfect ?

In a direct comparison to a CD player using a home made relay switching that allows a simple switch from listening position of synchronized tracks it is hard to pick the better source on most music i want puppy to always-be the best !
Sorry if some of these questions are obvious, just starting on the linux tweak game with limited understanding, but much enthusiasm