• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). Come here to have fun, be ready to be teased and not take online life too seriously. We now measure and review equipment for free! Click here for details.

Review and Measurements of Audiophonics I-Sabre V4 DAC

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
20,636
Likes
25,491
Location
Seattle Area
#1
This is a review and detailed measurements of the Audiophonics I-Sabre V4 DAC "HAT" for Raspberry Pi single board computers. It was kindly sent in by Audiophonics for review. The cost without VAT is 58.25 Euros which translates into US $58.25.

The I-Sabre V4 looks unusual as far as layout:

AUDIOPHONICS I-SABRE V4 Raspberry Pi HAT DAC Audio Review.jpg

A lot of board space is dedicated to the 3-pin IC to the center left. Lots of via stitches are used to allow the PC Board to act as an efficient heatsink.

There is a socketed 1701 op-amp which I assume allows people to scratch the itch of modding such devices. There is a proper oscillator in that larger "can" enclosure feeding the little ESS ES9023 DAC chip close to the RCA connectors. Speaking of those, as you see in the picture, they are quite beefy and high quality. And the large nut should allow secure connection to an external case.

There is a connector on the left for a display and different headers for switches and such.

Finally, there is an input for 5 volt in addition to what power the Pi can produce. I started my testing without it at first but then added it as you see later.

There is an extended socket that mates with the PI board with plenty of space below it for cooling of both components.

Raspberry Pi HAT DAC Audio Measurements
Let's stream a 1 kHz tone to the board and see what we get:

AUDIOPHONICS I-SABRE V4 Raspberry Pi HAT DAC Audio Measurements.png


Nice to see nominal 2 volt output. Performance is good in one channat at SINAD of 89 dB but not so in the other channel. I thought this was a power issue so I added the second power supply. In the process of that, I realized that there is some grounding issue as touching the outside of the RCA jacks resulted in improved performance (!). Used some grounding wires and got most of the way there without having to hold my hand on the RCA connector forever. :)
AUDIOPHONICS I-SABRE V4 Raspberry Pi HAT DAC Dual Power Supply Audio Measurements.png


Issues like this is why I recommend balanced XLR outputs in DAC. Anyway, even with improved grounding performance is still a bit shy of the cheaper HifiBerry DAC+ Pro:

AUDIOPHONICS I-SABRE V4 Raspberry Pi HAT DAC SINAD Audio Measurements.png



Jitter with and without the grounding/second supply shows what I was struggling with above:

AUDIOPHONICS I-SABRE V4 Raspberry Pi HAT DAC Jitter Audio Measurements.png


Multi-tone testing shows high level of intermodulation distortion products filling between our 7 primary tones:
AUDIOPHONICS I-SABRE V4 Raspberry Pi HAT DAC Multitone Intermodulation Distortion Range Audio ...png


And here is the response to white noise, indicating the response of the reconstruction filter:
AUDIOPHONICS I-SABRE V4 Raspberry Pi HAT DAC White Noise Filter Response Audio Measurements.png


One channel is show less attenuation and that single spike. There is definitely some noise issues here.

Conclusions
The build quality of the Audiophonics I-Sabre V4 DAC is quite good. Measured performance though, falls a bit short of cheaper HifiBerry DAC+ Pro. Measurements and some clean up of the design may get it up there but there is still a price premium. I am not here to gauge the usefulness of the extra hardware features. If those are important to you, then perhaps the price could be justified.

As it is, I am lukewarm on I-Sabre V4 DAC and can't recommend it. What I can recommend is Audiophonics as a store and company to do business with. For them to volunteer to send their product to me and participate here means a lot. So if you live in Europe, and have a need for the large suite of products they sell (both their own and not), give them some consideration.

------------
As always, questions, comments, recommendations, etc. are welcome.

Summer is sadly fading out into fall and with it, cooler weather will be upon us. And rain. So the panthers are hammering me for appropriate clothes to stay warm and dry. Problem is, I am tired of spending money on them so please, donate what you can using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 
Joined
Oct 4, 2018
Messages
13
Likes
61
Location
bordeaux
#3
Hello Amir,

I suspected that you will review this board after the 9038 one :)

The socketed chip is a MCU for power control functions. (power from push button, power cut from push button or software after RPI shutdown)
This board should be supplied with 7V input trought the DC socket.
The 7V is filtered with the regulator that is onboard.

Then after commuting push button pins, the MCU will switch on a transistor, that will power RPI and DAC section.
This is why it need a heatsink section on PCB as it's capable to supply a 2/3A current.

The board can also be powered directly from the RPI, but half of the board is not used.

About the ground issue, the ground DAC section is separated from main ground trought FB4 coil, I think this should be improved.
We already had some doubt about it on this aspect, but did not have the opportunity to take measurements.
We will do some checks on the board and find a solution to improve that.

Thanks for the review.

Ps. 58.25€ is more around 65USD
 
Last edited:

Guermantes

Senior Member
Joined
Feb 19, 2018
Messages
333
Likes
261
Location
Brisbane, Australia
#5
Thanks for the review, Amir.

I have one of these and have done some cursory tests with comparison to Topping D10 and D30 DACs. My conclusion was the Hifiberry is competent but the USB DACs were superior in the measurement results.

The Hifiberry's PCM5122 chip does have selectable reconstruction filters and these can be changed in the Alsamixer. The default is a reasonably gentle linear phase implementation as you identified but there is a steeper version ("high attenuation") that is also available. I believe some RPi audio player software installations, such as PicorePlayer, Moode and Volumio, expose these filters as settings in their DAC configuration pages.
Oops, I meant to post this in the Hifiberry DAC+ Pro review thread :oops:. Sorry about that.
 
Top Bottom