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New FIFO buffer for RPI/SBCs

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bvlabs

bvlabs

Member
Joined 2008
Update on Katana,
we were hoping to ship KATANAv1.2 by next Monday but One of the component required for the modification is unavailable and has a longer lead time than initially expected. There will be an additional delay of 2 weeks before we can ship.

P.S. - This is 12 day before...
 
C

chris14

Member
Joined 2018
What is the current opinion on the optimal configuration for
Katana ? Will addition of Isolator 1.2 allow for simple low cost SMPS power to the Pi and then add 1,2 or 3 higher quality psu's for DAC/opamp/microcontoller. Either Nirvana and/or more expensive linear power supplies could be used to power the rest of the stack. Based on your testing of v1.2 can you provide some guidance on this.
 
C

cdsgames

Member
Joined 2015
bvlabs said:
Update on Katana,
we were hoping to ship KATANAv1.2 by next Monday but One of the component required for the modification is unavailable and has a longer lead time than initially expected. There will be an additional delay of 2 weeks before we can ship.

P.S. - This is 12 day before...
Click to expand...




We are aware. We dont want to release anything until the testing has been completed and we are satisfied with sound. Please have patience , its coming soon.
 
C

cdsgames

Member
Joined 2015
Small update.


Components have arrived . Last decision for a particular filter will be made mid next week (after audio test) and manufacturing will start.



Noise on the opamp rails is now at at the floor of testing equipment. We have added a few capacitors , one of them 1000uF..



Sorry for all those delays but we wanted to make sure that SQ was tested and it took some time to get it right.


Katana 1.2 is better sounding then ver 1



Tomorrow we are releasing the new upgrade (field). It will work only with new Katana 1.2
 
pistollero

pistollero

Member
Joined 2016
cdsgames said:
Small update.


Components have arrived . Last decision for a particular filter will be made mid next week (after audio test) and manufacturing will start.



Noise on the opamp rails is now at at the floor of testing equipment. We have added a few capacitors , one of them 1000uF..



Sorry for all those delays but we wanted to make sure that SQ was tested and it took some time to get it right.


Katana 1.2 is better sounding then ver 1



Tomorrow we are releasing the new upgrade (field). It will work only with new Katana 1.2
Click to expand...

very nice news!

just one doubt. When you do tests and measurements do you test the balanced outs?

and about the digital volume, how it affects the performance specs of the dac??
 
sckramer

sckramer

Member
Joined 2010
Off Topic Breather ;D from Katana

attachment.php



WOW


This on top of piCore 4 Realtime / CPU Affinity -- really good!

The immediate obvious improvement is timbre and bass -- stops quicker / lets up more subtly, more dimensional, tuneful. Phasey highs coming forward / slicing thru the soundstage ie: more and interesting. Guitars sound crazy... to the bone. Amazing late night listening this past week.

fyi Plopped this straight on the same pi/piCore that was running the original DigiONE (fyi piCore Realtime improved this, and would not want to use anything else right now).

Work of art from an engineering perspective if you ask me!

( Sorry, please don't mind me -- continue on the Katana discussion :D )

* ref: DigiOne RCA/BNC output for RPI
* yggdrasil analog 2 dac used on so far, it sure isn't immune to digital transport
 

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S

soundcheck

Member
Joined 2005
soundcheck-audio.blogspot.com
To use the idle time I'd like to bring up another subject.

Which amp would be the perfect match for Katana ?

* direct DAC -> amp connection
* level/gain adjust
* single ended / differential
* no coupling caps

I am getting quite close to all above with my Anaview AMS0100. What I am lacking is the gain adjust.
Especially if going out differential from Katana, just using the digital VC would be too intrusive.
Katana does not provide analog level adjust like e.g. the beforementioned Benchmark DAC3. That's however not a feature I'd like to see on the DAC side anyhow, since it lowers your SNR. It would be better to have an amp with gain adjustment.

Any opinions?

Perhaps I should start a new thread on that subject!?!?
 
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wtnh

wtnh

Member
Joined 2015
soundcheck said:
To use the idle time I'd like to bring up another subject.

Which amp would be the perfect match for Katana ?

* direct DAC -> amp connection
* level/gain adjust
* single ended / differential
* no coupling caps

I am getting quite close to all above with my Anaview AMS0100. What I am lacking is the gain adjust.
Especially if going out differential from Katana, just using the digital VC would be too intrusive.
Katana does not provide analog level adjust like e.g. the beforementioned Benchmark DAC3. That's however not a feature I'd like to see on the DAC side anyhow, since it lowers your SNR. It would be better to have an amp with gain adjustment.

Any opinions?

Perhaps I should start a new thread on that subject!?!?
Click to expand...

A new thread is a good idea. Meanwhile, I think one option worth looking at is Allo's relay attenuator:
Relay Attenuator 10k Stereo

Using that approach (or similar) you can run a DAC wide open and connect directly to a power amp. They use Omron signal relays and thin film precision resistors. There might be a way to use two of them for differential applications - or a custom build would make for an interesting project.

Other options could include a motor-driven stepped attenuator or pot, but I like the relay approach better.

Cheers

Whit
 
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wtnh

wtnh

Member
Joined 2015
soundcheck said:
I do not intend to lower the DAC output signal.
That's what an/that attenuator does.
You drag down a great signal into the noise floor and that - now worse signal - you amplify by typically factor 20-30.
That doesn't make sense!
Fixing the amp gain is IMO the way to go.
Click to expand...

Sorry - I missed that what you looking for is a variable gain amp (VGA). There are plenty of IC's that do that (both analog and digitally controlled) but I don't recall ever seeing discrete audio power amps (at least high-end ones) that provide that capability. Gain is usually fixed by bias in the gain stages and messing with that would probably be suboptimal as far as linearity goes. And increasing feedback (to reduce gain) is probably not great either.

But if somebody finds an example, by all means, post it here. Or perhaps a new thread in the amplifier discussions.

Cheers

Whit
 
wtnh

wtnh

Member
Joined 2015
Markw4 said:
The digital volume control in Sabre dacs works well, without loss of resolution. No reason not to use it, unless Allo has chosen not to make it available for Katana. Still a good idea to choose gain staging wisely, of course.
Click to expand...

Yup - there is a good ESS slide deck describing their approach:
http://www.esstech.com/files/3014/4095/4308/digital-vs-analog-volume-control.pdf

They can achieve good results because internally they use 32-bit data paths in the Sabres.

Perhaps Allo can comment on whether this has been implemented in Katana firmware?

Cheers

Whit
 
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