Pi2AES Streamer Measurements and 5v PSU Mod Instructions

Pi2AES: https://www.pi2design.com/pi2aes.html

ChitChat:

The Pi2AES is a device I love. It’s very affordable at just $199, way less than most streamers especially good ones, and it has some absolutely exceptional performance, even beating out the $1000 Denafrips Hermes DDC.

If you’ve not seen my video on digital sources and would like a bit of info as to why they can be beneficial you can watch it here:

This article will provide some measurements of the Pi2AES as well as instructions on how to do the ‘5v direct’ reversible mod in order to use a 5v psu of your choice, and reduce noise.


Super TLDR:
– Pi2aes is great
– I2S > SPDIF > BNC > AES > Optical (For pi2aes anyway, this will not be the same for all devices)
– 5v PSU mod reduces noise slightly (if you use a good PSU)


Test Setup:

– Audio Precision APx555 B-Series Analyzer
– AudioQuest Carbon SPDIF, BNC and AES Cables (all 1.5m)
– ifi iPower 5v
– Netgear network switch, CAT7 Ethernet cable
– 44.1khz and 48khz real music played through device during measurement

Measurements:

Jitter:

To measure jitter, the device is connected to the digital input of the APx555, and the analyzer is set to analyze jitter, not audio content.
These measurements do not show audio/analog info, but instead show the spectrum of jitter, ie: time-domain inconsistencies.
This is the primary factor that a good streamer or DDC will seek to improve.

I’ll be posting some measurements of other DDCs/Streamers shortly, so if you’re not sure what to compare this to yet, you won’t have to wait too long!

This is absolutely AMAZING performance for a device this affordable
48khz and 44.1khz both wonderful, majority of the jitter content is 48khz/96khz noise, no random spikes at all!
BNC is not as good as regular coax out
Some added spurious jitter is visible on Optical out. Optical almost always has the poorest jitter of all the connection methods. But with the advantage of having galvanic isolation which can help to prevent ground loops. Generally, don’t use optical unless you NEED to do so.

Unfortunately I can’t measure the I2S output as the APx555 does not support differential/LVDS I2S, but as shown in my DDC video, the performance is absolutely stellar, and it did show measurably lower jitter in a J-Test than the already great performance coax output did. If you have I2S, definitely use it.

Electrical Noise:

The second issue that a good DDC or Streamer will seek to address is electrical noise. You don’t want noise from your source causing your DAC to perform poorly. Noise can have a direct, audible effect, such as hearing GPU-whine through your headphones/speakers, or it can have indirectly-audible effects. For example, causing clocks in your dac, or other circuitry, to perform sub-optimally.
Some dacs are more immune to this, and some will even have full galvanic isolation to in theory prevent any noise getting through entirely. But many smaller dacs are much more susceptible to it.

The Pi2AES normally comes with a 24v PSU, though can be used with a PSU up to 48v. This then goes through an on-board switcher to step it down to 5v. Personally I’m not a fan of this aspect, both because having an additional switcher when it isn’t needed seems odd, but also because the pi also runs on 5v, and so just having an input for 5v would make getting a nice linear PSU etc much easier.

BUT, there is a fairly easy mod to use any 5v psu of your choice instead of 24v. Let’s check to see if it improves things first:

We get pretty good noise levels no matter what, not at the same insanely good level as the zen stream but still very low.
But, we can also see that the 5v psu mod, where I used an ifi iPower, does make an improvement.
It’s also a hell of a lot more convenient to use a 5v PSU than a 24v one, so how do you do this?

5v PSU Mod:

You’ll need the following:


– Male to female jumper cables (Can be found on amazon for pennies)

Jumper Wire Male Female - Science Shop Bangladesh ৳ 2.00

– DC Barrel adapter (again, cheap as chips on amazon)

DC Barrel Plug to 2-Pin Terminal Block Adapter - Female

– 5v PSU (Rated for at least 2.5A) of your choice, the ifi iPower 5v is a great affordable option.


Instructions:

  1. Disconnect the pi/pi2aes from everything
  2. Open the top of the case to access the pins
  3. Make sure that the 5v Jumper shown below is installed. If you are wanting to power the pi separately, remove this jumper, but with this mod (and with the stock PSU) you can power the pi and pi2aes with one PSU by leaving this jumper installed.

4. Take two jumper wires. Ideally different colours, I like to use one ‘dull’ and one ‘bright’ colour so it’s easy to remember which one is 5v and which is ground. Connect the female end of one wire to the 5v pin and the other to the GND pin shown below

5. Connect the male ends of each wire to the DC barrel adapter. Make sure to put the 5v wire into the ‘+’ terminal and the GND wire into the ‘-‘ terminal. Screw the clamps down tight.
6. it should now look like this:

Purple wire is 5v, going to positive terminal
Grey wire is GND, going to negative terminal.

7. Plug your PSU of choice into the DC adapter and away you go!
You can also blu-tac or glue the barrel adapter to the outside of the case to keep things neat. There is a hole in the case just above where these pins are so it’s easy to feed them through as you put the case back together.

26 thoughts on “Pi2AES Streamer Measurements and 5v PSU Mod Instructions”

    • Hi Mike, what do you think about GoldenSound’s mod? Do you think he’s right that 5v is preferable?

      Reply
      • I can neither confirm nor deny the validity of his mode. 😉

        Unfortunately doing this mod violates the warranty and more importantly, bypasses the protection circuitry at the 24V input. Any voltage spikes, ESD, etc will pass into the device and the Pi.

        Reply
  1. I’ve been looking everywhere for thicker jumper cables, most are only 28AWG. Would you have any ideas for the pin end so I can use a custom wire? I am aware the power draw is not high, but when optimizing I don’t want a bottleneck there

    Reply
  2. Goldenone, thanks for all your work providing measurements on various devices. I noticed in an article from Aug 2020 you powered a pi2aes using a sotm sps-500 and said it was a big improvement from the stock psu, I believe this was before you had measurement equipment. Your test above with the iFi psu seems to show a small improvement. I’m on the fence about purchasing a sps-500 or uptone lps 1.2 for my pi2aes. Was wondering if you feel like the sps-500 significantly outperforms the iFi psu?

    Reply
  3. I got a PI2AES after watching the video where GoldenSounds discusses how good it is. For me, this is the BEST DOLLAR FOR DOLLAR COMPONENT I have ever encountered in my 30+ years in audio. I thought it was so great I bought a Fidelizer Nikola Signature 19v linear power supply ($850 retail) for it and my Roon Server (the linear power supply has 2 DC taps). The previous audio component that I thought was dollar for dollar the best ever was the MiniDSP SHD Studio. I still have the SHD Studio in my system, but there are products twice as much that do similar things. The PI2AES takes the place of $2500+ of products, and sounds better than those alternatives.

    Reply
  4. So it took a bit to load all of the above pictures, and now I see the interesting mod.
    Ok, I have a suggestion. The iFi iPower supply is good. And at $299 retail, I do not know of anything that sounds better (I have tested the 12v one out against a few different linear power supplies).
    However, if you step up to Uptone Audio linear power supplies, they are clearly better sounding. I went from a iPower 12v to a Uptone Audio Ultracap 1.2 linear power supply, and the Uptone was a clear step up in sound quality.
    Now Uptone’s Ultracap will not power the PI2AES as it only provides about 1 amp at 5v, but Uptone’s JS-2 Linear Power Supply puts out more than 2.5 amps at 5v. https://uptoneaudio.com/products/js-2-linear-power-supply
    I might get a JS-2 in the future to try this power mod and to drive my EtherREGEN (as the JS-2 has effectively 2 linear power supplies in it).

    Reply
  5. Previously I owned a Micro Rendu with The UltraCap LPS-1.2. This setup never really did anything for me, so I sold it.

    Based on Golden Sound’s review and comparison with other DDC units, I bought an RPi 3 B+ just to see what it was like. It has proven to be musically satisfying, so I immediately ordered a Pi2AES. I’m hoping this will be another improvement over the RPi alone. I plan to connect the Pi2AES to a Denafrips DAC via I2s.

    I’ve read that it’s best to keep the HDMI cable length short. Is there any rule of thumb on the maximum or Optimum length to use with I2s?

    Reply
  6. Charles, I used a Pi 4B for a Roon endpoint for quite a while before I a PI2AES. Hands down the PI2AES is better. Now I would experiment with COAX/SPDIF vs. HDMI (I2S) output on sound from the PI2AES when you get yours. I did a fair bit of testing (some of it blind) between the COAX/SPDIF vs. HDMI (I2S) in an extremely transparent reference system, and I ended up liking the COAX/SPDIF more. Now it was pretty close. I would also suggest a better Linear Power Supply. I use a Fidelizer Nikola Signature 19v LPS with 2 DC taps to power my PI2AES and my Roon Server (a NUC with Fiber ethernet out). The Nikola Signature LPS is not inexpensive (at $850), but for powering 2 devices, it is effectively $425 per device. It is quite good. However, I have not directly compared it to a 24v iFi iPower supply (at $299). Not a lot of companies make audiophile 19v+ LPS’s as you probably know.

    Reply
    • Keith F,
      Thanks for the information. I will be sure to try the COAX output. BTW, did you use BNC or RCA?

      I will be using the MeanWell Power supply like the one sold by Mike Kelly. I also have a Core Audio Linear Power supply that is capable of about 50 VA continuous. It is set to 12 volts but can be changed to 24V. Any experience with battery power?

      Presently I am using Roon for playback and the software resides on a Mac Mini. I have never tried any other software with the Pi. Any recommendations on that?
      Charles

      Reply
      • Charles, I am not familiar with any of those power supplies. However, the best power supply I have heard under $300 that can drive a PI2AES is iFi iPower one that sells for $299. Better than that is what I have is a Fidelizer Nikola Signature at $850. I have played around with a lot lesser (cheaper) linear power supplies (from $50 to $200+) and none of them can hold a candle to the two aforementioned power supplies sonically. I do hove some recent experience with battery power. I have a friend that recently rigged a deep sea battery system together to drive 12v devices. It sounded quite good. On just his DAC (a top line RME dac) his battery power seemed sonically the same as my Uptone Audio 1.2 Ultracap LPS. That Uptone LPS is really good (but it cannot drive a PI2AES as it is limited to 12v max). I wish Uptone made a LPS that went to 19v – 24v. You can use the same software (RIOPEEE) that you use on your SDcard in your Pi in your PI2AES. Also, I did setup my PI2AES at my friends house (to experiment as he does not run ROON) with Volumio and run JRIVER as playback. I must say it sounded really, really good in this configuration. However, I did not have ROON setup to compare. I have a lot of experience with JRIVER as a player, and from the first time I tried ROON, I thought that ROON sounded better for playback, especially a ROON system configured specific for ROON playback.

        Reply
  7. I have the Pi2AES up and running with a RPi 3 B+. I’m playing into a Denafrips Pontus II. It all sounds good. I’m very pleased. I prefer the I2S to the Coax connection. There is a greater sense of instrument separation. The USB from the RPi does not come close to the SQ of the Pi2AES. Well worth the cost of the unit.

    Reply
  8. I upgraded to RopieeeXL and note there is a significant difference in the sonic signature when using the Airplay Mode. The Airplay mode is more open and natural sounding. Any explanation for this?
    I’m using Roon primarily but also other playback applications that work with the Pi2AES when running RopieeeXL (Audirvana Plus, Bit Perfect, Pure Music, etc)

    Reply
  9. Have any of you run into negative effects as a result of long-term use of the 5v mod?
    I know Michael Kelly said it would “bypass the protection circuitry at the 24V input.” And consequently “any voltage spikes, ESD, etc will pass into the device and the Pi.”
    Seeing if you folks have encountered any of these issues (or heard of someone affected by this).
    Not that I’m doubting that these malfunctions could actually happen– quite the opposite, honestly. I just would like to know how prevalent these conditions have led to hardware damage.
    If you did this mod, is your Pi2AES still going strong? Even through power outages and storms, etc?
    I have the Meanwell PSU recommended with the stock config and think it’s ok… but I do have access to jumper wires to perform the mod if necessary.
    I also wonder if one of the cheaper [ Gumby; IIS > D70S].
    Lastly, I have a Burson Soloist 3X otw [and am selling my beloved SA-1. Interested? Shoot me a PM]. The Burson is also coming with the new Super Charger 3A upgrade PSU. I will most certainly use this one the intended way [with the Soloist 3X], but was curious if anyone knew whether the Super Charger would be compatible with the Pi2AES?
    Thanks and God Bless!!!

    Reply

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