Author Topic: DACs (BOSS / PIANO 2.1 and others...)  (Read 2434 times)

Offline Nidri

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Re: DACs (BOSS / PIANO 2.1 and others...)
« Reply #15 on: July 02, 2018, 07:15:13 PM »
^^^ Thanks for the update.

Offline BigAl

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Re: DACs (BOSS / PIANO 2.1 and others...)
« Reply #16 on: July 10, 2018, 09:13:19 AM »
Hi Andre

Thanks for the info. I've just started looking at the RPi and hats, and would like to know what the basic differences are between the BOSS 1.2 and Katana.

I realise that Katana will cost more, but what is the projected cost and the cost/performance differential compared to the BOSS?

Finally, how long do we need to wait...?

Thanks

Offline ALLO

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Re: DACs (BOSS / PIANO 2.1 and others...)
« Reply #17 on: July 10, 2018, 10:38:40 AM »
hi BigAl...

you are asking a question that is hard to answer.
there are many factors...what amp you use, cable, power supplies, speakers...

is the katana be better than the boss? yes, no doubt about it.
will you hear a difference? i cant answer that...

we will start selling the katana this month... but our SA distri will take some time to bring them in.

if we can organize a group buy on this forrum, we can assure to get them in faster.

regards



Andre
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kali / boss / digione / usbridge and more...

Offline ALLO

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Re: DACs (BOSS / PIANO 2.1 and others...)
« Reply #18 on: July 10, 2018, 04:52:08 PM »
Hi to all,

as many of you heard , we have been working on a new DAC .


We asked ourselves how its possible to bring true HIFI sound to the RPI. We wanted a price point thats accessible to everyone while blowing away any DAC made by anyone under 1000$ .
Lets see if we succeeded

1. DAC IC

First we chose a very capable IC , the ess9038q2m . This IC has excellent specs (theoretical THD+N at -120) and the analog stage (output) is left to the designer (more on analog stage below). One extra advantage of the ess9038q2m is DOP
Of course we used super caps and everything in audio path is film caps and thin film R.

2. Clocks

Any delta sigma IC is very sensitive to the clocks (jitter). We used the "ultra low jitter clocks from NDK [url]NZ2520SDA[/http://www.ndk.com/en/products/search/clock/1190972_1433.html]. We also made sure that power was filtered by 2 LDOs in series along with a HF filter. Noise tested is in uV. Of course we also used buffers (that also has its power filtered 3 times..)
What we achieved is the lowest jitter ever (390fs)

3. Analog stage

There are 2 kinds of analog stages , transfos and opamps. A lot of people swear by trans (with good reason) and others chose specific monolithic opamps. Still the consensus is that transfos are better as far as sound quality (but very expensive and bulky) and that opamps are better as far as THD+N numbers . If Opamps are used the quality of the PSU (opamps need dual rail 15V) is very important .

Still we felt that opamps CAN be better than transfos..

We concentrated a lot of efforts in this analog stage . You see , monolithic (integrated circuits) opamps suffer from the fact that not enough real estate is available on the silicon die .( excellent article https://sparkoslabs.com/audio-op-amps-g ... bandwidth/ )

So our choice was ultimately to build a discreet opamp (with IV stage we got 6 of them) while feeding it from a DC/DC convertor that has filters on input (+ LDO) and filters on output (+ LDOs) and of a course a common mode choke (each rail has independent filtering) for a total noise thats lower than 1mV

However building an opamp is not a trivial task . What we did is partner with Sparkoslabs.com and used his excellent design (thx you Andrew the wizard) . One review of those opamps https://www.monoandstereo.com/2014/08/s ... eview.html .

Each board is then hand trimmed (individually ) for DC offset (when board is warm to simulate conditions of a board that been running for at least 45 min)) and then programmed for THD+N compensation .



So in essence Katana dac is an excellent implementation of the Ess9038q2m in Master Mode (we are the first to do so) , with a discreet stage made by 6 opamps running in class A amplification . THD+N numbers (1Khz , 0 dbfs , a weighted ) at -112.75 !!!
Pricing at 249$ (US) and 259Eur (tax included) Release date 17 of July
Andre
CMO
ALLO.com
kali / boss / digione / usbridge and more...

Offline BigAl

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Re: DACs (BOSS / PIANO 2.1 and others...)
« Reply #19 on: July 23, 2018, 11:54:42 AM »
Any developments yet?  Was the release on track?

Online Scubadude

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Re: DACs (BOSS / PIANO 2.1 and others...)
« Reply #20 on: August 01, 2018, 06:50:37 AM »
The first Katana reviews are surfacing and seem to be very favourable. Would love someone to pit it against known high-end references in a He-man main rig.
"We should no more let numbers define audio quality than we should let chemical analysis be the arbiter of fine wines."  Nelson Pass

Offline Wietsche

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Re: DACs (BOSS / PIANO 2.1 and others...)
« Reply #21 on: August 05, 2018, 09:33:04 PM »
Hi,

If you want to have a look at the Katana, head over to my new dedicated review thread: https://www.avforums.co.za/index.php/topic,73522.0.html

My previous posts were moved there as well.

Cheers,
W