Reclocker (i2s ps jitter)

[ALLO.com]

Hi ,

in the past few months we have worked very hard on a new shield for RPIs/SBCs.

Basically the main idea belongs to Ian's. His hardware is actually superior to ours , mostly in the way he implemented the clocks and to the attention of the detail (like mounting xtals on a pcb supported by elastics ). So we credit Ian's idea and his great design.

Our hardware/soft is not a copy , its an implementation of the same idea. We use a FPGA and sram to buffer the DATA and we reclock bclk/mclk outside the FPGA using NDK (or Crystek) . The board has an eprom but its not HAT complaint (because of the space). FCC will be available for the board.

Main reason for making the board was to try to correct the audio clocks of SBCs and bring high quality audio to anyone that has an SBC around..for a great price.

feedback and thoughts on this?

[Ali Tait]

SBC?

[Wakefield Turntables]

Hi ,

in the past few months we have worked very hard on a new shield for RPIs/SBCs.

Basically the main idea belongs to Ian's. His hardware is actually superior to ours , mostly in the way he implemented the clocks and to the attention of the detail (like mounting xtals on a pcb supported by elastics ). So we credit Ian's idea and his great design.

Our hardware/soft is not a copy , its an implementation of the same idea. We use a FPGA and sram to buffer the DATA and we reclock bclk/mclk outside the FPGA using NDK (or Crystek) . The board has an eprom but its not HAT complaint (because of the space). FCC will be available for the board.

Main reason for making the board was to try to correct the audio clocks of SBCs and bring high quality audio to anyone that has an SBC around..for a great price.

feedback and thoughts on this?

feedback and thoughts.....

i didnt understand a bloody word of that, two many acronyms.

[danilo]

Weenie Jargon? The elastic band 'suspension ' is clearly impressive

[ALLO.com]

OK OK...
so here goes:

SBC: single board computer ... most know on the market is the Raspberry PI... people use it now to stream music, among many other things, but to stream it well, we built KALI , the add on board that plugs on top of the SBC (you can use the Raspberry Pi or our own... the Sparky).
see image attached to see how the system looks.

As mentioned, above, the main point of the reclocker board, is to sync the clocks and remove any jitter when streaming music from the SBC.

This greatly improves the sound quality.

[StanleyB]

Syncing the clocks does not necessarily equate to removing jitter.

[Wakefield Turntables]

Syncing the clocks does not necessarily equate to removing jitter.

Especially if the clocks are jitter prone, surely your only synching jitter to equal levels?

[ALLO.com]

hello,
we are actually generating a new clock from a low jitter oscillator that uses a master clock.

[lovejoy]

As with all of these things the proof is in the pudding.. How do we get to trying one of these?

If I get you correctly, this is a board that sits between the Pi and the DAC. I guess that is going to cause problems for any case that has been designed to house the two units when they are connected together?

[ALLO.com]

As with all of these things the proof is in the pudding.. How do we get to trying one of these?

If I get you correctly, this is a board that sits between the Pi and the DAC. I guess that is going to cause problems for any case that has been designed to house the two units when they are connected together?

correct Rich,
you can refer to the image i posted in an earlier post... you will see the KALI reclocker sitting between our Sparky SBC and Piano DAC.
as you can see, we opted for an open top/bottom enclosure, not a closed case... helps with airflow and only the spacers have to adjusted in case you want to add or remove a board.

for testing, you can please PM me.

cheers
Andre

[StanleyB]

As long as users of my DACs with the latest firmware upgrade don't get carried away with using this clock, I am not bothered. My own clocking process relies on the clock in the signal to generate an accurate reference. If that incoming clocked signal is no longer original, some or all of the extra data that is extracted from the valid audio signal may get washed away by a third party external clock if that external clock starts amending the clock phase and period. Over eager reclocking is one of the prime reason why digital audio can sound so synthetic through some DACs. A lot of the "goodness" in the signal can get discarded after being incorrectly identified as noise or a signal error. Soundstage, or the lack of it, tends to be a dead give away of an over active clock.

[ALLO.com]

As long as users of my DACs with the latest firmware upgrade don't get carried away with using this clock, I am not bothered. My own clocking process relies on the clock in the signal to generate an accurate reference. If that incoming clocked signal is no longer original, some or all of the extra data that is extracted from the valid audio signal may get washed away by a third party external clock if that external clock starts amending the clock phase and period. Over eager reclocking is one of the prime reason why digital audio can sound so synthetic through some DACs. A lot of the "goodness" in the signal can get discarded after being incorrectly identified as noise or a signal error. Soundstage, or the lack of it, tends to be a dead give away of an over active clock.

Stanley,

This is for i2s signals..basically the jittery clocks from RPI (bclk . lrclk) is replaced with a high quality low jitter clock . DATA is (buffered) and then synchronized using this new clock...how can the signal loose any info ?? We have measured the RMS jitter of the MCLK (ours) at 3.081ps but the floor of the oscilloscope is 1ps...so we think that jitter is actually lower. Any DAC will benefit from a better (low jitter/phase noise ) clock. Including yours.

[StanleyB]

Stanley,

This is for i2s signals..basically the jittery clocks from RPI (bclk . lrclk) is replaced with a high quality low jitter clock . DATA is (buffered) and then synchronized using this new clock...how can the signal loose any info ?? We have measured the RMS jitter of the MCLK (ours) at 3.081ps but the floor of the oscilloscope is 1ps...so we think that jitter is actually lower. Any DAC will benefit from a better (low jitter/phase noise ) clock. Including yours.
Been there, done it, and eventually ended up giving customers the option to select how the clocks connect or interact with each other. The famous option-3 in some of my firmwares eventually settled the argument for me.
Good luck with your endeavour. But there is a lot to be said against brickwalling the clock. Very fine detail on the boundaries of data errors are easily ignored by a fixed clock. One only has to listen to the kind of detail my SEG can reproduce in order to get an idea of what has often been stripped out by most other DACs. The smoking gun turned out to be the fixed clock.

[ALLO.com]

Been there, done it, and eventually ended up giving customers the option to select how the clocks connect or interact with each other. The famous option-3 in some of my firmwares eventually settled the argument for me.
Good luck with your endeavour. But there is a lot to be said against brickwalling the clock. Very fine detail on the boundaries of data errors are easily ignored by a fixed clock. One only has to listen to the kind of detail my SEG can reproduce in order to get an idea of what has often been stripped out by most other DACs. The smoking gun turned out to be the fixed clock.

Hi again,
I am not sure I understand your statement , clocks do not connect or interact to eachother. Furthermore DATA (on i2s bus( does not have "fine details" ..its just bits (0/1)
Frankly speaking , I think that your "famous option-3" might be nothing but marketing talk.

[ALLO.com]

A very solid contribution to the forum about our hardware from LoveJoy.

http://theartofsound.net/forum/showthread.php?46515-Allo-Audio-Piano-DAC-for-Raspberry-Pi/page2

[WAD62]

correct Rich,
you can refer to the image i posted in an earlier post... you will see the KALI reclocker sitting between our Sparky SBC and Piano DAC.
as you can see, we opted for an open top/bottom enclosure, not a closed case... helps with airflow and only the spacers have to adjusted in case you want to add or remove a board.

for testing, you can please PM me.

cheers
Andre

Hi Andre, just to confirm, is this compatible with a Pi (2 in my case), and it's associated DAC boards? IQ, audiophonics etc...?

[ALLO.com]

Hi Will,
yes you can use the KALI with RPI 2 as LoveJoy did (see his complete review in the link above), on the other hand, this current version of KALI wont work with Master DACs... only Slaves...