Kali The Goddess of Time
Every SBC has a crystal that it used to send digital signals to your DACs.
The accuracy of this crystal is very important in how well the DAC will transform the digital signal into analog sounds. Simply put: a better crystal means a better sound! Most SBCs use a very cheap crystal with lots of jitter in order to save costs.
Furthermore, there are 2 kinds of frequencies for digital files: 44.1Khz (wave files) and 48khz (streamed music). Some SBCs (like RPIs) can output only 48Khz, so imagine the degradation of the sound that was recorded at a different frequency.
Kali will solve both of those problems
First, it has a very low jitter NDK crystal feed by LDOs in series for ultra quiet power supply. Second, the FPGA will read the incoming stream, will buffer the DATA 0.7s while discarding the incoming clocks. Using the NDKs it will reclock the buffered data OUTSIDE the fpga (since fpgas introduce about 200ps of jitter) and provide a MCLK/BCLK that is direct from crystal, providing a jitter-free (almost) to your DAC.
Meanwhile, it will clock the file using the correct crystal (there are 2), fixing the problems outlined in the beginning.
Works great with Piano
Kali will not work if your DAC is a master. Dac has to be slave. We highly recommend our Piano 2.1 - they were designed to work perfectly toghether!
The million dollar question (actually $69): how does it sound?
Well, the music will "open up". The stage will sound bigger, more tri-dimensional. You will hear sounds, words, instruments that were drowned before in a sea of digital mud.
Is it worth it?
Do you enjoy a better wine/microbrewery beer, or anything will do? Do you have some medium/good speakers or you are using the cheapest PC speakers? Do you love music or just want to hear some beats?
We can’t answer the question for you. It’s your choice.
Features
- The basic design includes FPGA based FIFO board
- 22Mhz clock I2S input/output: 44.1k / 88.2k / 176k
- 24Mhz clock I2S input/outut: 48k,96k,192k
- FIFO Memory: 4MB SRAM
- Can be use with external Crystal Oscillators for MCLK or upgraded to a higher quality, multi-frequency clock that comes with automatic Fs switching and better performance
- LED indicators (Power, Full, Lock, Empty, Sample Rate, Mclk)
- DC power supply: (5V/3A) with Filter circuits
- Sampling frequency 48k,96K,192K is deriving from 24Mhz master clock , 44.1k,88.2k,176.k deriving from 22Mhz master clock.
- Automatically switching frequencies according to the input I2S signals
- Extremely fast and very low propagation delay Flip-Flops are added on I2s signals output from FPGA, for synchronization with MCLK before sending to DAC
- Ultra-low-noise voltage regulators for optimal audio performance
- Integrated EEPROM for automatic configuration (with write-protection)
- Purchase stand-alone Kali unit or get the Vana Player bundle (Sparky + Kali + Piano 2.1 + Volt + CM + 5V Adaptor + Acrylic Box)
- HAT Size / Not HAT compliant
Technical Specifications
| LED indicators |
Power, Full, Lock, Empty, Sample Rate, Mclk |
| DC Power Supply |
(5V/3A) with Filter circuits |
| Operating Temperature |
-25C to 85C |
| Board Size |
LWH = 58mm * 77.54mm * 23.8mm |
Question:
Why it’s the Reclocker in 2 differnet version (22/24 Mhz or 44/48 MHz) available? For what solution it need 2 different versions?
Answer:
This is to support different types of music files ,
“2 kinds of frequencies for digital files: 44.1Khz (wave files) and 48khz (streamed music). Some SBCs (like RPIs) can output only 48Khz “
Kali 22/24 Mhz will support only upto 192 Khz music sample rate ,
Higher frequency 44/48 MHz oscillators are used to support upto 384 kHz music sample rate
It’s like Single board computers à Kali à Piano DAC
When a music file pay from single board computer ,many single board computers use poor crystal where kali come in to picture – kali will provide better clock and to the DAC it will give buffered audio + sable clock from kali .This way we can avoid jitter and better reproduction of the recorded audio .
The precise timing of a digital music stream is vital to high performance, and if that isn’t done properly (usually because of poorly designed digital-clock circuitry) performance suffers.
Note -: Jitter is best defined as digital timing errors
