Preamp quandary for 2.1 or 2.2 stereo

[mdsimon2]

There's no dashboard, but at some stage during the 2x4HD thread, Amir estimates 90 for the HD's SINAD. Not a big step up I'll admit, but my experience to date is that 90ish with poor jitter rejection (eg Chromecast Audio) is around the point where I start to hear issues with the few DACs I've had.

Fooling myself? Could well be, but my guess is the Piano will be good enough. We'll see.

EDIT: Motu M4 looks great by the way, but in Australia, RPi+ Piano 2.1 is around $150 and the Motu is around $400. I'm sure it's well worth the extra, but I couldn't find one in stock anywhere anyway.

I think the Piano (and the 2XHD) are plenty good, obsessing over SINAD is often a rather useless exercise. Once you get it up and running I would take a look at running CamillaDSP on the RPi with just a pass through setup in PurePath. I've switched all of my miniDSP systems to RPis running CamillaDSP and have been super impressed. It is very easy to setup, super powerful, has a decent web interface and is very easy to integrate with other things (display, IR volume control).

Michael

 

[ad_fletch]

Ok thanks for that.

PurePath does seem a bit of a headache, so that's good to hear.

 

[mdsimon2]

I did not appreciate how inexpensive the Piano 2.1 is at 50 USD. I just bought one and it should be here tomorrow. It is honestly a really intriguing option considering a RPi + Piano 2.1 can be had for under 100 USD and seems ideal for 2.2 or 2 way active streamer based systems.

I have some basic measurement capability that should be able to quantify performance of the Piano, I'll post measurement once it arrives but do not expect any surprises as all Allo products seem very well designed.

Michael

EDIT: Just realized that the Piano 2.1 does NOT have dual local oscillators like the Boss. I am hoping that by resampling everything to 48 kHz or 96 kHz in CamillaDSP the RPi's 19.2 MHz clock will produce acceptable jitter results. It will be interesting to see how J Test results differ between 44.1 kHz and 48 kHz, as I understand it 44.1 kHz should be quite poor as the 19.2 MHz clock cannot be divided by an integer to yield 44.1 kHz. I guess if it is an issue you can always add a Kali reclocker but that is an additional expense.

 

[ad_fletch]

Yes, on another forum I read that resampling to 48kHz is recommended. Will be interested to see whether I can hear any difference though.

 

[mdsimon2]

Got to play around with the Piano 2.1 using a RPi4 running Ubuntu Server 21.04 64 bit.

Measurements are exactly as expected, about 93 SINAD at -1 dbFS as specified by Allo. Surprisingly there is no difference in J Test results between 44.1 kHz and 48 kHz sample rates, which brings up some questions which I am certainly unqualified to answer 1) Is the single RPi frequency clock actually an issue? 2) If it is an issue is a J Test really the way to quantify it?

My biggest issue with the Piano 2.1 is that it is not a true 4 channel DAC (I could have known this by reading through the DIYaudio thread in more detail, DOH!) so you cannot use something like CamillaDSP to implement a crossover, you need to use PurePath. Of course you can use CamillaDSP for overall correction but you cannot apply correction to individual speakers / drivers. In this respect it acts exactly like the 2X4HD (which also presents itself as a 2 channel DAC to ALSA) although the 2X4HD is substantially more powerful. I probably won't play around with this any more but it does seem like a good option for a low cost 2.2 streamer DAC.

Michael

44.1 1 kHz

44.1 J Test

48 1 kHz

48 J Test

 

[ad_fletch]

Interesting, thank you.

I was reading a blog the other day about quirks with Motu M4 in ALSA too, so I wonder what is the best value, true 3+ channel Dac which would be fully compatible with CamillaDSP now….

Anyway, I can try the 2.1/2.2 firmwares from DIYAudio. Will see how I go.

wish Australian delivery were as quick as yours.

 

[mdsimon2]

Interesting, thank you.

I was reading a blog the other day about quirks with Motu M4 in ALSA too, so I wonder what is the best value, true 3+ channel Dac which would be fully compatible with CamillaDSP now….

Anyway, I can try the 2.1/2.2 firmwares from DIYAudio. Will see how I go.

wish Australian delivery were as quick as yours.

I have a M4 and it works great with CamillaDSP on a RPi4 running Ubuntu Server 21.04 64 bit. I’ve used it with a variety of input devices (DDRC-24, HifiBerry Digi I/O, HifiBerry DAC+DSP, ALSA loopbacks) and all work flawlessly. My one complaint would be lack of master volume control on all 4 channels but CamillaDSP easily solves that.

It is also really great for making basic measurements, the measurements I posted above are actually from a M4.

Michael

 

[ad_fletch]

So I got the Pi 4 yesterday and have now set up moOde. Bit of a learning curve but nothing insurmountable. Haven't tackled CamillaDSP yet but the EQ interface is mercifully straightforward.

Using Meizu DAC for a while because my Audiophonics order (Hypex amp + Piano 2.1) is stuck somewhere in the French postal system

 

[ad_fletch]

Now over 3 weeks and no tracking update on my amp + Piano DAC. Audiophonics are sympathetic, but all they can do is raise a query with the French postal service.

Anyone else have a similar exp who might be able to reassure me that my order isn't lost?

Hoping it's the tracking that's at fault and it's actually still on its way....

 

[Epos7]

Now over 3 weeks and no tracking update on my amp + Piano DAC. Audiophonics are sympathetic, but all they can do is raise a query with the French postal service.

Anyone else have a similar exp who might be able to reassure me that my order isn't lost?

Hoping it's the tracking that's at fault and it's actually still on its way....

That's a bummer. Shipping in general is a nightmare right now. If it makes you feel any better, I paid for a monitor in May that is finally scheduled to be unloaded at port in 5 days.

 

[ad_fletch]

So the package finally arrived, but...

The box felt more like a bag! Was wondering whether I was particularly unlucky, but a French friend of mine reported that all of his boxes from home arrive looking like this

Anyway, after getting over my initial jitters, I unpacked the nCore amp and the Piano 2.1 DAC, and I'm happy to report they seem to be fine (thanks for padding them well @Audiophonics).

The DAC fits nicely in the HighPi case I bought for it, and integrates perfectly with moOde too. Had to download a firmware package from Allo, but now it's set up in 2.1 mode with >80Hz out of channels 1+2 and <80Hz out of channel 3 (default slopes for time being).

I was a little worried about the Pi4's temps with the HAT on, but so far it's stayed under 60 degrees C. Will have to monitor it as Summer ramps up here (can get to 40+ degrees here in Melbourne). The case can accommodate tiny fan if need be.

With a little tweaking (set high attenuation filter in DAC chip settings and used moOde's built-in PEQ to implement REW filter recommendations), it sounds great to me. Noise seems no more audible than the Meizu Pro, but I might review that statement when I get the amp working instead of running it through my AVR....

I am (as you can imagine) very eager to test the amp, but I ordered XLR-RCA cables from Ghent Audio at the same time, and I'm still waiting for them. I can at least report that there is a slight buzz when the amp is switched on (as I expected from the other threads on this amp), but it is only audible if my ear is a few cm from the case, so I'm relieved about that. Will update when cables arrive.

 

[Audiophonics]

So the package finally arrived, but...
View attachment 162521

The box felt more like a bag! Was wondering whether I was particularly unlucky, but a French friend of mine reported that all of his boxes from home arrive looking like this

Hello,

Indeed the Post Office did not take care of your package... we are sorry!
If you notice anything afterwards, you can contact us and we will do what is necessary.

Good listening to you!

 

[ad_fletch]

So I finally received the Ghent A15 cables.

Initial room measurements with REW don't show any major differences from my AVR, which was expected.

The Hypex obviously has way more clean power though, and shows up differences between sources ruthlessly.

In short, if you're on a budget like me, I can heartily recommend RPi + Piano 2.1 +nCore for 2.1 or 2.2 system with adjustable crossover.

The next step up SINAD-wise would be a 4 channel USB audio interface, but then you need to do the crossover in software and be more confident in Linux than I am....

I will probably aim to get a MiniDSP SHD one day, but for now I'm happy with the integration and overall sound quality.

 

[ad_fletch]

Oh my, MiniDSP just sent a newsletter about its new Flex preamp/streamer.

If it lives up to the specs on its datasheet, we could be looking at a very tempting option with full 2.1/2.2 management and optional Dirac Live around the US$500 mark.

Even a balanced option. Very tempting.