OTICE: If you choose China post air mail free shipping and the order less than $30 ， for the low profit ，the packages all will send by hongkong post without tracking number ，hope you can understand .normally deliver time about 15-30days (brazil need about 30-60days).sometimes need a little long by accident .Please be patience and don\'t worry .If the order less than $30 and you need send with tracking number .please choose hongkong post need $2.11 for the tracking number .Thank you !!
Semi-finished kit! Including the board with all of the elements! SMD components have to weld and test good， straight welded components need buyers themselves
AK4490EQ DAC decoder! AKM official standard circuit! The official circuit effect is guaranteed not recommended to buy unauthorized changes to the circuit!
This version supports I2S / DSD decoding!
AKM new decoder chip， high-performance 32-bit stereo DAC 120 db dynamic range can be achieved.
Pure soft control (on-board microcontroller MCU)! Individually designed using I2S / DSD signal input!
I2S data up to 32bit 768KHz sampling rate! NOTE: I2S I2S format required data standards， do not support the left or right-aligned format.
DSD supports 2.8M 5.6M 11.2M sampling data (DSD64， DSD128， DSD256)!
Support for DSD better than AK4495 with AK4399!
Support soft control volume (VOL I accept a single joint Potentiometer 10K)!
Each channel 3 5534 (a total of six two-channel) sound rules Naiting!
Sense of hearing: sound balance， good dynamic， high-frequency detail， IF thickness charming， low-frequency full， the sound field is very good， realistic strong， warm sound Naiting type version!
Features: Volume control with soft， you can set five kinds of internal digital filter mode (provided by a jumper on the board to the MCU high and low signal， and then implemented by the MCU soft control!)， You can set the DSD sampling rate (also via jumpers setting)!
Jumpers on the board Features (K port)， K port a total of six jumpers be set on the board. Nos. 1-3 to patch internal digital filter mode (see below Table 1)， No. 4，5 jumper settings DSD sampling rate (see below Table 2)， No. 6 jumper for switching PCM (I2S) / DSD mode. No. 4，5 jumpers valid only in DSD mode.
! ! ! K port 6 feet short connected to PCM mode， not less then empty the DSD mode! It can also be set via I2S interfaces on the 1st pin DSD / PCM， I2S interface to the 1st input low as PCM mode， I2S interface number 1 Input high level of DSD mode.
PS: I2S interface using a foot switch PCM / DSD should disconnect the K port on the 6th， it may cause damage to the external signal source! ! !
K port 5 feet generally do not need to change the default.
Table 1:
K port filter state
1 foot 2 feet 3 feet
Empty Empty Empty Short delay sh-arp roll off filter
Empty shorting empty Short delay slow roll off filter
Short empty empty Sh-arp roll-off filter
Short Short empty Slow roll-off filter
Random random shorting Super Slow roll off Filter Enable
Table 2:
Unused
. . .
Electrical Characteristics:
PCB Size: 12 * 11cm
Power Supply: Dual analog supply DC 15V (! Attention dual 15V DC input， AC or pick the wrong line connecting incorrectly can cause permanent damage to the circuit)， digital power AC single 9-12V (here AC!).
Since this board analog section power supply is a dual DC input， so the need rectified and filtered power supply
Since this board is I2S / DSD signal straight into (without digital reception function)， required coaxial
Explanation:
On board volume control (VOL port) using potentiometer， but not really potentiometer to control volume， but read potentiometer midfoot voltage ratio (the percentage voltage VCC to GND) with microcontroller， then by Write DAC soft control internal registers to achieve volume control， so long as good contact can potentiometer， potentiometer quality is good or bad and will not affect the sound quality.
VOL mouth below 5 pin no use but also what not to take otherwise it will damage the board! ! !
Board official standard analog part IV LPF circuit. Circuit is as follows.