Simple power supply tweak using HDMI - amazing improvement!

jesper

Ops, "rechecked"... Should of course say "reclocked". Auto correction error...

jesper

So, I got the Allo Boss DAC today and installed it using RuneOS ver 0.4b, which have pre-configuration in the graphic user interphase (GUI). That´s the same used when doing the above tests.

First I listened to the sound with my setup of sound via HDMI to the Emotiva preamp as mentioned above, but now adding the Boss DAC - just plugging it in on top of the RPi and turning on I2S. The result, I was curious to what this very precise clock could do a clock which reclocks the RPi when I2S is turned on having less jitter than 0.63 nano seconds - well below the hearing level of variation in jitter.

First impressions with HDMI setup
It was better, but only slightly better than with above setup. This means that the capacitors above did the trick of very much reduce jitter of the RPi. That´s kind of an amazing simple trick (in combination with iFi iPower) to reduce the infamous RPi´s jitter problem. And note I´m playing 44.1 kHz, which have been reported give most problems. That is a highly recommended upgrade to most users of the RPi, but don´t use some shitty capacitors and expect good results - use only really good ones with low inner resistance.

Next setup was using the RCA out (analog) from the Boss DAC
This sounded somewhat different, big and wide picture, good, but less natural sound and a bit thinner. Ok, now I have to say that the Boss DAC is new and didn´t get run any hours to "break in" circuits, it´s just out of the box sound. And my preamp didn't´t sound so well either when out of the box as it does now. What I can say now is that my Emotiva UMC-200 beat the shit out of Allo Boss DAC so far. This is not to say that the Boss DAC is bad - it´s not - it´s quite nice! But what it means is the Emotiva UMC-200 is great stuff! Just so you know, the Emotiva preamp has a Room EQ, but this was turned off wile comparing.

In my setup, the Allo Boss DAC so far have not been worth the about 85 € of total for getting the Boss DAC - the most expensive single component used yet and the one producing the least added benefit in my setup, at least for now. But I look forward to see how it will play after having been "broken in". The Allo Boss DAC should not be rulled out in my setup, and fine Emotiva is High End gear, maybe not a fair comparison. It can be said though that the Emotiva benefitted immensely from reduced jitter!

Well, I´ll be back

giving a report on how the "broken in" Allo Boss DAC sounds.

jesper

Ok, an update on the Allo Boss DAC:

I kept playing it now for a while, but still up in about 20-25 hours, so it´s not yet run enough time for final decision. I can say it´s improving, but the mid range and voices I'm not satisfied with.

I decided to look into the Boss DAC's analog power and found that the DAC uses 3.3V, not 5V. this means there needs to be some proper capacitor to stabilise the 3.3V as well. Out with the DAC and solder another capacitor onto the board

I took a polypropylene capacitor of 1.5uF (ICEL MPL 160V K5 1.5uF 1%) and soldered it to the Boss DAC board at the big capacitor located between the PCM5122 and the left (white) RCA. It looks blue and yellow on allo.com's pic of the Boss DAC.

Now, the troubles in the mid range and voice are gone and the sound opened up - just an amazing improvement!
Now the sound is already fantastic! Wow!

So, the power supply of 3.3V MUST have a bigger, better capacitor to get the ALLO BOSS DAC to perform better in the mid range.

Now get out your soldering iron and a few capacitors and rock the place! I´d like to hear from someone who dared to try this tweak too. You won´t regret it (unless you don´t know how to solder)!

hondagx35

Hi jesper,

thank you for sharing this.

Frank

Stephane

This means that the capacitors above did the trick of very much reduce jitter of the RPi.

Hello,
Do you have a screen-copy of the oscilloscope showing the improvement?
Thank you.

DJ le Roi

jesper wroteOk, an update on the Allo Boss DAC:

I kept playing it now for a while, but still up in about 20-25 hours, so it´s not yet run enough time for final decision. I can say it´s improving, but the mid range and voices I'm not satisfied with.

I decided to look into the Boss DAC's analog power and found that the DAC uses 3.3V, not 5V. this means there needs to be some proper capacitor to stabilise the 3.3V as well. Out with the DAC and solder another capacitor onto the board

I took a polypropylene capacitor of 1.5uF (ICEL MPL 160V K5 1.5uF 1%) and soldered it to the Boss DAC board at the big capacitor located between the PCM5122 and the left (white) RCA. It looks blue and yellow on allo.com's pic of the Boss DAC.

Now, the troubles in the mid range and voice are gone and the sound opened up - just an amazing improvement!
Now the sound is already fantastic! Wow!

So, the power supply of 3.3V MUST have a bigger, better capacitor to get the ALLO BOSS DAC to perform better in the mid range.

Now get out your soldering iron and a few capacitors and rock the place! I´d like to hear from someone who dared to try this tweak too. You won´t regret it (unless you don´t know how to solder)!

This sounds very interesting! Is it possible you show me a photo of the modification?

jesper

Hi Stephane,
No oscilloscope pic as I don´t have one, but I can assure you that the sound improvement is very obvious, at least in my setup. I trust my ears better than a test pic, but of course that would be interesting to see. If someone that has an oscilloscope and could do this simple tweak I would also like to see the pics. I guess someone having moderately good speakers might not get the same results, but I´m quite sure it will be obvious to the listener. The speakers I have are high end - very good indeed - which, after this tweak they really prove to be. I actually disconnected my subwoofer for music listening as it goes so deep and I even have to cut off 2 to 4 dB on the sub channels (active speakers), and these are 6,5" only!

The tweak is so cheap (10-20€) that I honestly think it´s worth trying. If you have some good capacitors laying around, like I had, the tweak is more or less for free. It´s for sure THE BEST improvement for the least money in my setup.

Kind regards,
Jesper

jesper

Dear DJ le Roi,
Pics, of course. As you see it´s in the tweak stage - no box, etc.

but that will come later.

Here is the 1,5uF polypropylene capacitor soldered to the Boss DAC:

: IMG_5920-1.JPG (37.03 KiB) Viewed 13499 times

Here is the tweak with two capacitors, mentioned above, soldered to the 5V power input of the RPi fed with 5V from iFi iPower:

: IMG_5922-1.JPG (42.45 KiB) Viewed 13499 times

Here is one of my speakers. Note the stones under and on top. These really improve the overall sound and especially the bass becomes very deep having these, as it will not move - about 9 kg/stone! Also note the power cable to the speakers (red, black, yellow) and the thin blue ones. They are twisted, which improved the overall transient response.

: IMG_5924-1.JPG (32.02 KiB) Viewed 13499 times

Kind regards,
Jesper

jesper

Ops, speaker pic rotated to the side. Lean your head to the left...

jesper

Thanks Frank,
I like to learn too and learned a lot from others sharing their wins too. I still have to learn more about the RPi and programming it. I like to get a good Room EQ installed. Any tip on this is appreciated.

I have been tweaking speakers and audio equipment for quite some years, but I must admit these RPi:s are fun to tweak!

I have another tweak in the pipeline too - adding a Class A non-feedback balanced output direct from the DAC output. It´s LC Audio´s ZAPfilter 2, a really nice one. It´s without OP:s, just pure transistors. That might just set everything up into the strata...

Kind regards,
Jesper

Audiohrdwr

Jesper,
thanks for the info.
On the BOSS which uses 3.3V we have 4 caps:
1> 4.7uF ceramic after LDO
2> 22uF film
3> 0.1uF film
4> 0.22 F !!! Super cap. That's 220,000uF

We know that it takes about 50h to break in the film caps but from reports we got, it can take up to 2 weeks to break in the super cap.
Judging by your feedback and set up, you have golden ears and we don't doubt you heard an improvement after adding your 1.5uF capacitor but could it be that the capacitor in question was already broken in ?
Please confirm.
regards
Andre

jesper

Hi André,
The 1.5 uF polypropylene capacitor was not new but never used.

As you might be aware of, all capacitors of same size and materials does not always have the same specifics and characteristics in audio. What I used was a quality audio filter capacitor. Capacitors have different parameters and one important one is its inner resistance, which should be as low as possible, because it acts like a resistor in series. If that inner resistance is higher it blocks the delivery speed of electrons in and out of it and that, in audio, will result in a less stable voltage output. A wobbling output, even if very little, by my test results obviously disturbs the signal.

In this case the midrange improved noticeably, and it opened up the whole soundstage and especially voices became more natural and less "compressed".

If you have the BOSS DAC I urge you to try my two capacitor tweaks - it´s worth it! (at least if you have quality amp and speakers).
Kindly,
Jesper

bertie

Hi Jesper, these posts are so interesting!
If I had the slightest soldering skill

I would have new capacitors soldered right way.
Still, at the rate new circuit boards are appearing I doubt it will be long until some manufacturer advertises a new 'low internal resistance' RPi with crazy-ass capacitors dwarfing the board and I will be their first customer.
I see you have an Emotiva processor, I use their stereo balanced XSP preamp and, like you, am very happy.
Thanks for posting your improvements

Waluan

jesper wroteOk, an update on the Allo Boss DAC:

I kept playing it now for a while, but still up in about 20-25 hours, so it´s not yet run enough time for final decision. I can say it´s improving, but the mid range and voices I'm not satisfied with.

I decided to look into the Boss DAC's analog power and found that the DAC uses 3.3V, not 5V. this means there needs to be some proper capacitor to stabilise the 3.3V as well. Out with the DAC and solder another capacitor onto the board

I took a polypropylene capacitor of 1.5uF (ICEL MPL 160V K5 1.5uF 1%) and soldered it to the Boss DAC board at the big capacitor located between the PCM5122 and the left (white) RCA. It looks blue and yellow on allo.com's pic of the Boss DAC.

Now, the troubles in the mid range and voice are gone and the sound opened up - just an amazing improvement!
Now the sound is already fantastic! Wow!

So, the power supply of 3.3V MUST have a bigger, better capacitor to get the ALLO BOSS DAC to perform better in the mid range.

Now get out your soldering iron and a few capacitors and rock the place! I´d like to hear from someone who dared to try this tweak too. You won´t regret it (unless you don´t know how to solder)!

Hi Jesper,

Well, you inspired me! I have a Boss DAC v1.2 and I run it off independent power supply, ifi as well. Although I plan to do the power supply tricks you suggest in the future the Cap on the analog path of the DAC caught my eye as the easiest and fastest to try. So I tried to find a cap with similar specs to the one you mentioned and ended up buying a (Mumford Mcap Zn – 250 VDC 3% tin films condenser, Capacity (µF): 1.5).

And we soldered it. My impressions the middle frequencies became more crisp and clear and instrumental separation was better, also since I have a sensitive (right) ear that squeaks at high frequencies, it now is much more comfortable. REALLY GREAT! In short I felt most music sounded more audiophile and clean even when some of it clearly wasn't audiophile produced music.

However.... The bass went to the background and shrunk, loll. I mean it really went down.
I won't go back since i like the new sound more, but what can I do to save the low frequencies from limbo?? lolll

I am no expert at electronics but I am considering upgrading the super cap which Allo and others claim is a reason of these rich lows the Boss DAC is popular for.

The one on the Boss is rated at .2f 5.5v. will replacing it with a 1f or 2f alleviate the problem?
Would love to hear your and others suggestions on how to solve this issue.

Thanks again for your inspiring post!

Best,
Nasr