Pi2 Design Idiot-Proof Ready-To-Go RPi/AES Streamer

@e.schell :

So - yep, what @fraggler said:

 

You guys are amazing! Very much appreciated as always!

 

We are releasing a new version of Mercury V3 this week. Mercury DAC has the same digital guts, but adds a stereo DAC output. Decent performance at -106dB typical, but very low jitter of course, because it is tapped off the internal I2S bus. Price will be $599 and the digital only version is already reduced to $499. With the pandemic driven price and availability issues behind us, we can now go back to the original pricing we had a few years back. Our costs are still a bit higher than before, but $499 is where we always wanted to be.

We will be releasing the docs and test results by next Monday. Tell all your friends!

 

I have a Mercury SBAF rev P8. Maybe there is a way to separate the power of CM4 and the rest? I see some connection P13 - EXPANSION POWER CONNECTOR. I wonder who it is for? I ask because in the case of PI2AES Pro, connecting the power PI and HAT separately definitely felt an improvement.

 

No t really without some board surgery. Sorry.

 

Starting now, we are shipping mercury V3 with the built-in analog DAC. We have changed the name to mercury V3 DAC to reflect this. The documents are up on the website and we will be posting some test results over the next few days, so people can get an idea of quality of the analog output.

This is an added value function, the price stays the same at $499. We are realize that not everybody wants a DAC added to their digital streamer, but it gives you lots of options for your set up. The ability to drive a more sophisticated DAC via the digital outputs while at the same time, connecting a small set of powered speakers or headphone amp, etc. gives the ultimate flexibility to how you consume your music.

 

The Pandemic is done and the supply chain has finally normalized. Thus we already announced reduced pricing on Mercury V3 (now including analog DAC). Now we are reducing pricing on the PI2AES 2.0 (was $299, now $199) and the PI2AES-LITE (was $199 now $149). Now you can get some of the best, highest rated network streamers for less!

 

As promised the jitter and THD plots for Mercury V3 DAC are up.

Power was from a Meanwell 12V supply. A linear may improve this, but that is not something we can test. I mean, we could use our $1K benchtop linear supply, but that's instrumentation grade and not something the average user would have access to.

Some key observations:
Average jitter is 252 psec. which is the same as the SYS-2722 Analyzer
Jitter plot shows very low peaks, though obviously not as good as the SYS-2722 in loopback
Note that the SYS-2722 does not use the same method of jitter plot that the later Audio Precision APx555B does.
Analog out jitter is very clean, but the noise floor is limiting
Analog out THD is good, not great. But the 2nd order dominates so hopefully a bit smoother than some

That's it for now. Questions, comments, kudos, flames, etc are welcome!

 

Once upon a time (circa 2022) we had plans to release a lower cost version of Mercury. But the pandemic and subsequent shortages crushed that dream! Even now the CM4 is not widely available in the 4GB or 8GB no eMMC version. Thus we switched Mercury to the actual PI single board. We were able to reduce the cost a bit as other parts finally freed up.

But, now we are able to move forward on a lower cost version using a 2GB CM4 module (seems that's the sweet spot). Going back to the CM4 and removing AES BNC and XLR greatly reduced the size. Features of what we are calling the Mercury--Mini (aka MERC-MINI) will be as follows:

CM4 Module with WiFi and 2GB DDR Memory
Front Panel SD-Card Socket
GIGe Ethernet
1x HDMI
1x USB2.0
SPDI/F via RCA
Toslink Optical
I2S over HDMI
Mini-Noise Nuke (same design as Mercury V3)
Separate Ultra-Low Noise LDO for Clocks and Digital Circuitry
Upgraded Clocks to support up to 384Khz PCM and DSD512 (via DoP)
5V (3A) Power Input via USB-C connector
No Internal Switching Power Supplies, All Linear

Captures from PCB Design:

 

@Michael Kelly , are the dimensions finalized? I'm curious how this would fit into a Schiit Modi+Magni/Vali stack.

The 3A power you mention is I presume what you plan to suggest (or offer?). Do you have an estimated total current draw for the device, assuming output connection just to a DAC and no other peripherals? Wondering if the 1A PS I'm currently using would be adequate...

 

dimensions are 4.5" (114.3mm) wide x 4.7" (119mm) deep x 1.4" (35.5mm) high

1A would not be enough. I will need to test to know the absolute minimum.

 

Is this Mini streamer the same as the one in Mercury V3 DAC?

ETA for delivery and price?

How is it controlled? App? Volumio? Others?

Will it support AirPlay 1 and 2? Chromecast?

Does it offer digital USB2 out?

Do you offer a trial period?

 

ETA is end of January/early February. Price is $399.

It will run standard pi software. AirPlay, chrome cast, etc will depend on the software running.

Unfortunately we are too small to offer a trial period. But we will send a few out for bets testing as we did for the original Mercury.

 

And it has USB out but it's not anything special. No isolation or filtering.

 

it will be interesting to see how that performs connected to Schiit Audio Unison USB input.

 

Same performance as a pi by itself. No need to buy our unit for that.

 

I'm curious: have you looked into improved USB outs, if that's a thing? Many of us have moved to USB audio for its greater flexibility, and DACs are getting better at handling it (as with Schiit's Unison).

 

Thinking the same myself. Something similar to Allo’s USBridge, but perhaps with a more elegant solution than a separate clean power source to power the board (which makes me wonder why?).

 

Or maybe a full-blown Usbridge Signature replacement with no unmaintained ICs on the board

 

I should note that the direct 5 V input on the Merc-mini will allow you to run an external low noise linear. There are no switching power supplies in the box, so the USB port would benefit from that low noise power. It's the USB signals that don't have any special filtering.