Raspberry Pi2 and Hifiberry Digi+: A cheap transport that made me happier

Yes, in order to keep the comparison fair between the RPi3 and my PC, I intend to run coax to my Mutec for reclocking. Also, my DAC does not have a USB input.

 

@tboooe
Thanks a lot for taking the time to list your system. Nice PC, hdplex psu must be amazing.
Cheers for the sonus faber speakers!
Please keep us posted as digi+ arrives on your impression comparing it to the mutec with the Pi.
It's unfair to compare given the price difference but very interesting.

 

Wow, this is perfect. I was just trying to do this yesterday with picoreplayer (as a Squeezeplay thing) and couldn't do it, as I kept taking an error. I wanted to put it through the Berkeley audio USB to see how close it sounded vs. the computer, and I just ran out of time. Your impressions running it through the Mutec helps a lot.

That's a very nice system you have there. I have the I/O card here, if you want to borrow it, PM me. I live just north of the OC. I ran it directly to the Gungnir Multibit, and it sounded flat and dry. Hopefully the Mutec alleviates it. For some reason I thought you lived in Oregon.

Oh, I also have an extra Raspberry Pi case if you need one. I overordered.

 

FYI, Check out my reply here (Scott Kramer) further down in the thread:

https://support.hifiberry.com/hc/en...6543509-Digi-Linear-Power-and-DAC-Suggestions

Also the power supplies I went with:
http://www.diyaudio.com/forums/digi...y-dac-pro-hw-mods-anybody-24.html#post4689840

Semi related:

vid on my channel:

 

Hi scott, Nice job and thanks for posting this!
I see you chose the lt3042, same as I did. Any feedback on this diyhnk kit?
I really wanted to do go down that road, but then something happened in this thread:
http://www.superbestaudiofriends.org/index.php?threads/raspberry-pi-i2s-to-spdif-hat.1990/
Have you checked it out?

 

Hi Vastx,

Thanks!

Yep been using this for awhile now, linear power made all the difference & made it really really good for music on a big system! Surprising how sensitive SPDIF is.
Still need to build those power supply boards, waiting on the transformers anyway. Those are just the most extreme low noise I could find. The linear power supplies I use now are ~200uV noise! But sooooo much better then a wall wart switching supply thru the usb.

Yep see that new board design... interesting if it can improve on the PLL. Great power layout and interested on how you can filter the ground from the pi!

No effort lost really... can just swap this board in... reuse the 0.8uV noise linear supplies still for the board,pi,wifi -- can't hurt

I'll probably rip the TOSlink off and put on a BNC tho

 

Please let me know if what you think about the lt3042 board. I read that you tried the ADP series regulator.
What transformer are you going to use? Diyhnk told me to supply 9vac for 5V operation. Isn't that a lot? a 7Vac transformer more suitable? It should provide about 10volt after the rectifier bridge, right?

 

Found this place just now... so I'll keep you filled in on progress and results!

I went with 7V, 25W Talema's (for 3.3V and 5V) hope that works!

9V will probably be fine... will run slightly warmer, you'll have to keep an eye on it at first.

 

Looking forward to reading about your results with the LPS. And I followed the links back on the Hifiberry discussion about minimizing components and the pizero, and measurements. Very helpful.

 

What kind of max amperage have you guys measured for a Pi 3 + Digital out hat +wifi? I was thinking about using one of the DIYINHK lps boards, but most of them are pretty low current (or at least much lower than the 2-2.5A suggested for just the Pi 3). I could build something discrete like the AMB sigma11 (have built one before) where I can do offboard sinking, but those are a bit larger than I wanted to put into my case.

 

Please forgive the total noob question...but to clarify..you are supplying 7V AC to the LT3042 board? Not 7 V DC? I've never heard of that but I am far from being an EE. I think I failed my one EE lab in college! Anyway, how important is the input source if the LT3042 is so good?

 

@fraggler Take my advise with a grain of salt, it is just an opinion.

Screw the suggested current. That is an advice for the worst case scenario (i.e. all 4 usb ports occupied).
My Pi2 plus digi+ draws a little more than 300 mA while streaming music with Moode. Pi3 is a little hungrier. Take a look here:
http://raspberrypi.stackexchange.co...s-pi-2-power-consumption-and-heat-dissipation
Worst case scenario is 750 mA in full load. And moode or volumio won't use more than 2% of cpu load to play. But I'm not considering other peripherals you might want to use (mouse, kb, usb self powered hard drive).
I wouldn't go under one Amp if you plan to power all with a single rail, supposing you don't wanna use external peripherals.
Hope this helped.

Edit - The digi+ absorbs 50mA but I think Micheal's board is gonna absorb a little more (Linear reg., more clocks).

 

@tboooe Yes... AC. Alternating Current. What did I do wrong?
The board includes a bridge rectifier and a levelling cap. Why would you want to provide DC to the board?

Edit- You could provide DC to the board bypassing the bridge rectifier and entering in the cap holes. Usually it is not a good idea to provide dc before the bridge with another dc psu. The voltage drop happens for the GND too causing different GND potential. But again... Take it with a grain of salt. I know very few about electronics and less about how to explain it in english.

 

You didnt do anything wrong...I am total noob at electrical stuff which is why I am just asking to make sure I understood correctly. I have never heard of anything needing 7 VAC, but of course my experience is very limited. I am just used to things needing DC voltage, other than stuff plugging into the wall of course. I have a few DC linear power supplies so I was hoping I could use those instead of getting one to supply 7VAC. I just needed clarification which you provided and I appreciate it.

 

Fantastic. Thank you, Vastx. At most, I will use wifi in addition to the two boards using Volumio - that means just about any of the DIYINHK power supplies will work nicely. Since most of them are two-packs, I can run the Pi 3 and the digital hat off of separate supplies (off of the two secondaries of the transformer).

 

No, not really. The LT3042 is rated 500mA (the kit I mean, not the ldo itself) because of the coil filter in the input section. And the ADM7150 is a single rail. That leaves only the TPS7A4700 option available if you want to run the pi and the hat with separate rails and have a safety margin (I don't know how safe, I don't trust too much those heatsinks).

Again if you don't want to connect anything else you COULD use the lt3042 (at worst you could have to add a fan or bypass\replace the filter coil), if you plan to connect something else or a different use (e.g. 1080p video streaming) I would not consider it.

As I said personally I wouldn't go south of 1A. And in any case I would not use any transformer with secondary voltage north of 8\9Vac.

Please try to check this with someone who, unlike me, knows what he's doing

 

I have a general sense of how to put things together, I just like ready made kits so I can reduce my amount of errors. If your Pi2+Digi only draws 300mA during playback, I think I could get away with the LT3042. Most likely, though, I am going to go with the TPS7A4700 and possibly swap out the heatsinks for bigger ones. That will give me roughly 1A for each of the Pi3 and the digital hat off of a 7V transformer. Still poking around.

 

Here are those 7VAC Transformers, just testing, easy to record it at the same time.
Transformer Video

 

Anyone tried the Ifi ipower with the raspberries?

 

Here are the LT3042 power supplies--