Hifiberry DAC+ Pro - HW mods anybody?

[Tomax]

Are there more informations about sabreberry32 and a source where I can buy this DAC?

 

[Tomax]

Forget my question.
Found infos in Post from soundcheck. Maybe it's also a little too expensive for a HAT DAC in my eyes.

 

[greinedo]

@Soundcheck,

First, I apologize again for the slowness of my responses... work and some other activities have kept me busy the last few weeks.

On the Mamboberry with two supplies:

1. The Mamboberry board has a jumper connection. If the jumper is in place, the Pi is powered from the Mamboberry's supplies via the expansion header 5v pins. If disconnected, the Pi needs to be separately powered. They showed this in the previous iteration of their website, but I didn't find it mentioned now. I asked them via email about doing this and they confirmed it was designed to allow the DAC and Pi to be separately powered and did not caution me away from that.

2. While I do have the Mamboberry DAC Hat and Pi powered from entirely separate supplies (down to separate transformers and power cords), I do take care to make sure their final grounding point (sort of a star-ground) is at the DAC/Pi unit, so that they stay at the same ground potential. In my experience this is a common configuration, I've only taken it a step farther by separating the power cords too. I used this to good effect back in the middle 90s with my massive modification to a Magnavox CDB-650 (5 supplies, 3 power cords) and more recently my fully linear cMP/cPlay PC-based player (13 supplies at last count, if I keep it in service it will go up to 14 supplies, with 5 power cords). And the Sony HAP Z1-ES stock has 3 transformers and 6 supplies. While I did not increase the number of supplies when I modified it, I did wire in separate power cords for the digital side versus D-A & analog out side.).

When I tested both the MamboBerry and the HiFiBerry DAC+ Pro, I started running them basically stock with a single supply. It was only after getting a feel for the sound that way that I went to multiple supplies. IN EVERY CASE separately powering the Pi sounded better in my setup. In my experience, that is always true, but I like to confirm it and not leave a stone un-turned.

Also, IMHO, the MamboBerry power supply setup is the best among the R-Pi DAC hats I've used and looked at (as far as can be told from pictures and experience). That it is designed to take AC from an appropriate transformer to drive an on-board linear supply that in the basic configuration feeds both the DAC and the Pi helps ensure a poor-sounding SMPS will not be used with the unit. AND the supply is fairly sophisticated and well-designed, with what appear to be good rectifier diodes, an extensive set of filtering capacitors, and great-sounding best-of-class regulators from TI (the same ones John Swenson prefers for his designs such as the Regen, the uRendu, and the Bottlehead DAC). And they use a 2nd regulator cascaded to for the DAC to somewhat isolate it from the electrically-noisy Pi.

This supply is a strong driver of the unit cost compared to other units. For example the two regulators they use in single quantities are $5 and $3... the one used on the HFBD+P is $1. Only the DurioSound Pro units begin to approach this level of sophistication and they use one of the same regulators to power their DAC chip).

Where I think there is room for improvement on the MamboBerry is to power the clock separately from the DAC. And of course use two clocks with the DAC Hat in master mode to feed the Bitclock to the Pi as the I2S signal clock source... but that would require an extensive re-design AND a new driver... or one could just get the SabreBerry32, which while it does not have as sophisticated of a power supply setup, does run in master mode AND uses the highest-quality clocks of any of these units.

And in my experience, upgrading power supplies is a lot easier to do and do fairly right than restructuring the clocking and I2S signal feeds.

Greg in Mississippi

Hi !

I bought a Mamboberry after reading several posts here and I must admit I'm also convinced. In addition, I own a Hifiberry DAC but it's sound quality is disappointing for me, reason why I found this thread.

My Mamboberry is powered with the 2 power supplies : the regular Raspberry and the advised toroidal transformer 6V AC, also bought on Mamboberry's site. I could not use the 6V AC power supply alone (without the regular Raspberry power supply) because in that case, the Raspberry Pi 2 model B had strange behavior at boot (hdmi output flickering and some other strange problems). A rainbow icon in the top right corner appeared also. Later I found on ModMyPi | How do I power my Raspberry Pi that this is a low voltage indicator. It seems that the 1A is not sufficient for my specific setup (Raspberry model, OSMC, usb dongles and hdmi port,...)

Anyway, I connected both power supplies and everything is working as expected.
The sound quality is amazing and far superior to what I could reach with the Hifiberry Dac, especially bass, stereo image and some magic things I cannot express. The Mamboberry seems to have by default everything I need on-board. It drives a cheap tube amp (EL84/12AX7) and some nice full-range speakers. What a sound !

The metal case with double power supply connection to Mamboberry. I need to drill one additional hole :
https://drive.google.com/file/d/0B3AonlTstB87dXdxWklZcFlWQ00/view?usp=sharing

External DIY power supply with toroidal transformer 6V AC :
https://drive.google.com/file/d/0B3AonlTstB87TEM5aTY3QV9VdHM/view?usp=sharing

The 2 DACs. What a difference !
https://drive.google.com/file/d/0B3AonlTstB87b1BYVlhQbzg3c2s/view?usp=sharing

Greetings from France !

 

[sckramer]

Hi !

I bought a Mamboberry after reading several posts here and I must admit I'm also convinced. In addition, I own a Hifiberry DAC but it's sound quality is disappointing for me, reason why I found this thread.

Greetings from France !

This thread is for the Dac+ Pro, never tried the Dac+, the Pro is average also unless you at least use linear power thru the GPIO as a starting point. Hope this helps, recommend you buy the Pro also & experiment! What you've read on this thread does not apply to the standard Dac+

 

[clivem]

I don't have the datasheet for the ESS9018Q2C.

The real elephant in the room with the SabreBerry32 is that ESS have "forbidden" the release of an open source driver, for the SABRE9018Q2C. Greg, if you do manage to obtain that datasheet from Shaw without signing an NDA, please let me know.

 

[pistollero]

Hi !

I bought a Mamboberry after reading several posts here and I must admit I'm also convinced. In addition, I own a Hifiberry DAC but it's sound quality is disappointing for me, reason why I found this thread.

My Mamboberry is powered with the 2 power supplies : the regular Raspberry and the advised toroidal transformer 6V AC, also bought on Mamboberry's site. I could not use the 6V AC power supply alone (without the regular Raspberry power supply) because in that case, the Raspberry Pi 2 model B had strange behavior at boot (hdmi output flickering and some other strange problems). A rainbow icon in the top right corner appeared also. Later I found on ModMyPi | How do I power my Raspberry Pi that this is a low voltage indicator. It seems that the 1A is not sufficient for my specific setup (Raspberry model, OSMC, usb dongles and hdmi port,...)

Anyway, I connected both power supplies and everything is working as expected.
The sound quality is amazing and far superior to what I could reach with the Hifiberry Dac, especially bass, stereo image and some magic things I cannot express. The Mamboberry seems to have by default everything I need on-board. It drives a cheap tube amp (EL84/12AX7) and some nice full-range speakers. What a sound !

The metal case with double power supply connection to Mamboberry. I need to drill one additional hole :
https://drive.google.com/file/d/0B3AonlTstB87dXdxWklZcFlWQ00/view?usp=sharing

External DIY power supply with toroidal transformer 6V AC :
https://drive.google.com/file/d/0B3AonlTstB87TEM5aTY3QV9VdHM/view?usp=sharing

The 2 DACs. What a difference !
https://drive.google.com/file/d/0B3AonlTstB87b1BYVlhQbzg3c2s/view?usp=sharing

Greetings from France !

Hi, test the mamboberry with archphile player. Disable everything on the kernel optimizations file and enable sox on mpd.conf for 24:192000 and tell me what you ear.....

 

[greinedo]

This thread is for the Dac+ Pro, never tried the Dac+, the Pro is average also unless you at least use linear power thru the GPIO as a starting point. Hope this helps, recommend you buy the Pro also & experiment! What you've read on this thread does not apply to the standard Dac+

Thanks for the clarification and advise. Nevertheless, my goal was at least to indicate a potential problem of low voltage when using power supply thru GPIO only (at least with Mamboberry, due to on-board regulator I suppose). Using the dual power supply layout seems to me in any case more safe.

 

[soundcheck]

Havn't been around for a while. Mountainbike season currently draws my full attention.
And that "instant notification" feature of DIYA doesn't work reliable. (This might not be such a bad thing though )

@sckramer
Great to see that the VDD jumper tweak makes sense as an entry level tweak.
Hifiberry should see this. With a simple change on the routing - which would not cost anything - they would gain soundquality and finally that DAC
could be 100% supplied by a single supply.
Beside that they should replace the 0R with a jumper - the way all others are doing it.

Thx also for checking out the load situation. Looks there's plenty of headroom left.

What I don't understand is why you use a >5 inch wire antenna and pins and plugs in between.
I'd be using an inch of wire-bridge soldered straight towards VDD. I'd also add a decoupling cap on top.


@all
I figured out even more rt-kernel optimizations, which led to small, but worthwhile improvements again.
I know -- that doesn't help you much.
However, it shows that there is still something to gain on that side.


Just to let you know. A friend of mine also bought the MamboBerry. He's quite happy.
He used the iPower 9V. He reported things get very hot this way - with that with the rectifier still in place!
I'd guess that things get worse when passing by the rectifier, the way Greg used to do it with his DC supply.

I was also wondering what new 3,3V regulators to use - just in case I'd decide to go that way. My plan would still be to use the iPower as 5V basic supply.
I came across these low-drop-outs from inmate mravlca (I forgot if somebody mentioned these before).
2 of them cost more than the HifiBerry DAC alone - still reasonable if comparing them to other top quality regs.
Hmmh !?!? I'm not really convinced to go that route.

Next thing I'm gonna try now for sure is the VDD-bridge-mod. Thx again scramer for checking it out.

Qs:

1. Anybody tried my output-stage-bypass (filter, jacks and routing) tweak? I can't recall any feedback on that one.
2. Anybody played around with the default DAC-filters under Linux?

 

[sckramer]

@sckramer
Thx also for checking out the load situation. Looks there's plenty of headroom left.

What I don't understand is why you use a >5 inch wire antenna and pins and plugs in between.
I'd be using an inch of wire-bridge soldered straight towards VDD. I'd also add a decoupling cap on top.

Hello!

At this point I'm trying things without altering the board to the point it can't be put back, did at least use a short jumper since then. Linear power and then this 3.3v seem like the heavy hitters since it is improved big time. Not a struggle to hear the difference like interconnects etc.

I'm thinking of making tiny ADP150 daughter-boards that can be added, wire it correctly then, just a thought tho-- I'm keeping it simple, to repeat it on friends dac's etc.

 

[sckramer]

Don't laugh , but to experiment I am borrowing that ADP150 circuit on the DAC+ (see the lash up in the pic), to power the 3.3V on the digi+ (similarly bypassing the pi 3.3), best my PSAudio DL3 dac has ever been! Using 2 linear 5V supplies.

 

[sckramer]

Linear supplies

What do you guys think about these:

4.17uV Ultralow noise DAC power supply regulator 3.3V/5V 1Ax2 - DIYINHK

1.0uV Ultralow noise DAC power supply regulator 3.3V 5.0V 800mA - DIYINHK

0.8uV Ultralow noise DAC power supply regulator 3.3/5/7V

The 1uV noise version is based on an ADP7150

Any suggestions on a good transformer for these?

Thanks!

PS. The 3.3v ADP150 on Dac+ is rated at 9uV noise.

 

[BruceInOz]

What do you guys think about these:

4.17uV Ultralow noise DAC power supply regulator 3.3V/5V 1Ax2 - DIYINHK

1.0uV Ultralow noise DAC power supply regulator 3.3V 5.0V 800mA - DIYINHK

0.8uV Ultralow noise DAC power supply regulator 3.3/5/7V

The 1uV noise version is based on an ADP7150

Any suggestions on a good transformer for these?

Thanks!

PS. The 3.3v ADP150 on Dac+ is rated at 9uV noise.

I have the 4.17uV version. Seems good (I haven't measured it's performance) and having a dual selectable supply is great for flexibility. 6VAC at the input feels about right - regular has low dropout and more volts end up in heat...

Note documentation is non-existent for these products

 

[sckramer]

@BruceInOz

Sounds good!

Transformers:

15VA Power Talema Seal Toroidal Transformer 7V 9V 12V 15V 18V with Install PCB | eBay

 

[Greg Stewart]

@sckramer,

Funny, I just posted some suggestions on regulators and background info on the SDTrans384 thread:

If you are looking at a single 5v supply, consider a Salas Reflektor.

If you want to do separate supplies for the different rails, consider Acko's AKD75s, IanCanada's TPS7A4700 regs, or OPC's Paralleled LT3042 boards... or LiFePO4 cells.

For tips on good supplies for digital circuits, see these posts by John Swenson:

Sonore microRendu - Ethernet to USB output - Page 49

Uptone Audio JS-2 Power Supply and Linear Fan Controller Installation (Experience, Pictures, Results)

"Audiophile capacitors in Power Supply - A real advantage or not?

The three regulators you posted have the same three regulator chips as the three I suggested.

I think any of these would be good.

John Swenson is sticking with the TPS7A4700s.

OPC prefers the LT3042 to the ADM715x series:

http://www.diyaudio.com/forums/vend...-here-bal-bal-se-se-lpuhp-18.html#post4686934

And Acko and the Pulsar Clock people swear by the ADM715x's.

I don't think you could go wrong with any of them.

But read the John Swenson posts.... he strongly suggests that the highly varying demands of digital circuits (especially processors) need higher-current supplies than one would expect from the average or static current draws. So consider a higher-VA transformer.

And do check out the LT3042 one from DIYINHK a little more closely.... I only know of it coming in a tiny package with a much lower current capability, their supply does not look right to me (unless a new package has been released). That is why OPC released his paralleled LT3042 boards.

Greg in Mississippi

 

[sckramer]

@Greg

Thanks! I'll try to catch up on what you've been doing with power supplies.

In the mean time I'm going to order 2 of these:

0.8uV Ultralow noise DAC power supply regulator 3.3/5/7V 1.5A*x2 - DIYINHK

That will give me 4, selectable 5V/3.3V supplies, nice and flexible.

Edit: yeah I see what you mean, you can see the tiny surface mount parts that are the actual LT3042, but then it also has the normal looking thru hole with heat-sinks regulators (in their pic), hmmm
maybe the ADP7150 is a better choice.

And I'll go with the 25W transformers (up from those 15W):

25W Power Talema Seal Toroidal Transformer Install PCB 7V 9V 12V 15V 18V 22V New | eBay

Need to get my digi+ up & running on that, and can try it on the Dac+ PRO.

PS. Yeah, capacitors are more complex then we realize, and the interactions in a circuit, check out youtube eevblog #859, #742

 

[sckramer]

0.8uV Ultralow noise DAC power supply regulator 3.3/5/7V 1.5A*x2 - DIYINHK

What AC input voltage should I go with... I was thinking 12V:

(There's no info about this, went by the regulator whitepaper)

Can choose 7V-22V on these:

25W Power Talema Seal Toroidal Transformer Install PCB 7V 9V 12V 15V 18V 22V New | eBay

Thanks!

 

[Greg Stewart]

I expect they are using a pass transistor to increase the current... a single LT3042 is limited at about 200mA. See page 26 of the datasheet for the likely circuits.

AC voltage... dropout is a very low 350mV. 7VAC with a diode bridge gives you about a 10V rail, 9VAC about 13V. For a 5V or 3.3V output, I'd go with the 7VAC.

In my setup where I am feeding two sets of 4 paralleled LT3042, I am running about 6.4VDC into each quad-set of regs, with one doing 5V out and the other 3.3V.

Greg in Mississippi

 

[sckramer]

Ah, thats what they did, re: page 26, to up the output from 200mA-- hope it's not to much a compromise. Also went with the 7V transformers, Thanks!

Now I get the pic's you've posted showing the paralleled regs... thought those were all stand alone, to power various parts of the dac.

 

[illinimdg]

Hope this isn't hijacking the thread, but I'm interested in building my own linear PSU for a RPi and HiFiBerry combo. I've drawn up the following based on a few circuits out there. It's only $21 in materials, and I think the performance should be quite good. Any thoughts or suggestions?

 

[sckramer]

32/384 Upsample to disable PCM5122 filter

Scott... I should add this info on filters (in case you didn't already know it), that DACs use different filter sets based on the sampling rate of the input signal and typically use a less onerous & obtrusive / better-sounding filter when you feed it a higher sampling rate. So even being able to upsample to 192 could possibly bring some benefits, again after some fiddling with filters. BUT AFAIK, with the PCM51xx chips, the biggest bang is brought by upsampling to 352/384 with the right filters.

Greg in Mississippi

The moode 2.6 tr1 is working with the D+Pro now, so tried 32/384 up sampling...

Looks like it does it, but then changes to 32/192 going to the dac... so maybe the hifiberry driver limits it?

Music does play fine this way, no stress on the pi3.