Allo Boss DAC review

https://sites.google.com/site/computeraudioorg/cable-break-in

Burn in theory, tell me what you think…

FYI Audioquest explains something similar about their wire

Hi Edward,

Totally agree!

In my opinion, even after soldering wires or components, it needs new break-in / burn-in…
Even in mains section or psu section. Difference is VERY noticable. Normally I take 150 Hrs as rule.

Sometimes audio components just act as a very good bottle of wine :slight_smile:

Regards,
Alex

Haha, if it really ‘burn out’ than you got a reliable issues, can send back and get a new ones😀! Actually the main component in the electronic circuits that requires burn-in is mostly the capacitor. These guys are chemically bonded with two electrodes, one positive and the other negative. When a voltage is applied to the capacitor for a period of time, the chemical reaction inside the capacitor becomes more stable. Once the stability has reached, the performance of the capacitor will peak over its lifetime until the chemical inside the capacitor start to degrade, then it is time to change.

Big caps like the ones use in power supply are notoriously hard to burn-in because of its sheer size. Burn-in approximately less than 100hrs are quite common but some can go up to 300hrs. One will hear the sound improvement as it go along until no improvement is observed.

On our film capacitors we ask 50h of burn-in (small surface). Janis is burning his unit as we speak. Lets see if (any) improvements are detected .

I did today retesting of the Allo Boss DAC after 4 days non stop burning-in with looping burn-in track.

Yes, there is overall improvement, very positive impact on mid-low, but no improvement in high frequencies.

Overall: even greater dynamics and presence, richer audio reproduction, and better segregation of different frequency sounds

Mid-low: much better natural, deeper and solidly round voice that now is less metallic that Kali-Piano combination (was opposite in beginning), as well disappeared the washing-off of voice with low frequencies

High: no real improvement here, Boss is still missing presence of high frequency reproduction, it is also sounds less transparent, and less accurate that Kali-Piano combination

Also I compared once more with Audiophonics 9018K2M, but only on 24bit, as it has quite audible high frequency distortions on 16bit playback, even with all extra wiring and serial drive of ALSA synchronization. Audiophonics has still the best natural and velvety voice, but less dynamics and bass, as well is somehow in the middle between Boss and Piano in high frequency reproduction.

Summary:

  • Boss is the best price performance DAC, and I think especially good for Rock, Rap, etc.
  • Kali-Piano is the best high frequency DAC, great for Pop
  • Audiophonics 9018K2M is the best voice DAC, good for vocal and classical music, but unfortunately it doesn’t work with 16bit music files, unless up-converted by Roon DSP and then not bit perfect

Talking about “golden ears”.

Basically there is a subset of people that can hear small details that usually escape most people (like me for example). Janis has those…

Not happy with the feedback of "mid to hi frequency reproduction problems " from above , our engineering team has taken the BOSS and started reviewing it from the top. We started with the filters , LDOs , Oscilators …nothing. Ground was checked , jitter , again nothing.

At last we arrived at low pass filter in the end of the analog signal. On the Piano TI has in the datasheet a LPF with 73Khz cutoff, in the new datasheet they have it at 150Khz (so different resistors and capacitors). What we did, is we took the old capacitor value and added the new resistor to it…basically a cutoff frequency of 16Khz (-3db). From 8-20Khz the LPF is introducing noise , instead of cleaning hi frequency noise thats above human hearing(but still can distort the audio)

We are rushing now, testing the unit with the right values and sourcing in time for mass production.

I am now a firm believer that Janis has " golden ears"…

3 Likes

Will the Boss DAC work with DietPi?

Yes it will

:+1:

Thanks for the prompt reply

Great review @Janis , and it’s awesome to see that @allo.com reacts and tries to improve the Boss before mass production :+1:
I can’t wait to read an update by @Janis with this new improved version.

BTW, I’d really love to read a comparison between the HifiBerry DAC+ pro and the Piano Boss. If I understood correctly they both use the same DAC chip, but with a radically different board integration…

Again, thanks for this great review.

So did the LPF get fixed in the production version of the Boss?

yes it did, we are shipping corrected versions to reviewers and customers since Friday . Expect feedback this week .

1 Like

The boss was tested with an RPI, right? Considering to buy it, would it make any difference to go for the Sparky instead of an RPI 3 for it?

The BOSS as a master DAC only works on RPI

OK - thank you for the info

Recieved my Boss DAC today, installed it on a clean DietPi RP3 but the DAC is not recognized. I selected the Boss DAC but aplay tells me no dac found. Do I need to install a driver?

I will check with Dan if driver was added

Hi, posted this on DIY Audio as well. Does it make any sense to add the "Boss’ on top of the Kali and would that even work?

Nope , Boss already has the clocks

OK thanks!