- Storage: Solid State Storage (SD etc.) connected to FPGA based dev. board.
- Control: Simple controls (play/pause, stop, next, prev) with on board switches.
- Display: No display, maybe a 7-segment.
- Output: Direct SPDIF generation -I should check if it is possible with readily available gpio voltage/current options- or on-chip sigma delta dac with external output filters.
- Clock: Master or slave.
Limited storage :( User unfriendly :(
Absolutely silent ! Bit-perfect ! Jitter ?! Synchronization ?!
What do you think ?
Anyone have attempted to do such thing before ? Anyone wanna try ?
How about GHI Electronics?
They already have USBThumb MP3 Player. Some Mod (maybe tiny CPLD) will generate I2S signal from WAV file.
Re: ultimate source
Why would you bother with SPDIF, if you already had the data in the FPGA? You could just output directly to I2S.
Because spdif or aes/ebu is standard on commercial dacs, and I dont want to build my own dac due to smd parts.
Has anyone tried to implement ide/atapi interface ? Is it hard ?
I should search for a dev. board with those kind of connectors/interfaces for audio.
I found them.
First guy does not use VS100x (stream processor), generic DAC.
So it means he can generate I2S signal (can be easily converted to SPDIF) from WAV file on SD Card.
I found VS1033,
This is new version of MP3 decoding chips, and it has I2S output.
So If you get one of MP3 DIY players using VS1001 etc then replace to VS1033, you can get WAV(44.1/16) to I2S portable.
VS1033 normally uses 12.88MHz clock (for 48kHz) so it have to be changed.
I was reading the CD player transport thread today and it got me thinking. Then I looked down and saw the thumbdrive and said viola! The things are ubiquitous, very inexpensive, and could hold most of a CD or two of compressed lossless audio. First you rip the CD with CD Paranoia to get the best copy. Then copy to a thumbdrive. This way you have a backup on the hard drive "just in case" as well as the original. Thumbdrives don't care about scratches and fit in pockets easier than CDs, plus you can put whatever mix of music on each one you want. Just USB -> Decoder -> DAC.
May I know the link to that cdrom thread?
Is there info in that thread (or another diyaudio thread)
to diy a decoder that takes a thumbdrive and outputs
I2S or spdif?
Thanks for any info.
with tiny modification.
This "ultimate source" is an interesting idea. I was thinking in the car for these holidays.
There are some issue.
(1) Read SD card by MCU
Some DIY MP3 player already does it.
I think Daisy MP3 is good base for modify.
(2) make I2S signal
Almost Electrical DIYers does not care it. they are using VS1011 or something (MP3 stream decoder). by using VS1033, it can be done. but...
(3) make I2S signal 44.1kHz/16bit faithful to sourse, high acculate clock
VS1033 contains SRC and output is 48kHz. It can not be acceptable for audio maniacs.
So we need some hardware to make this conversion.
(a) PIC RAM buffer to FIFO
2 x 74HC164 and some glue logic, PIC firmware can do it.
SN74V245 is 4K x 18 fifo, $9 at digikey.
(c) FIFO to I2S
11.289MHz(256fs) as master clock, /4(64fs) as bit and counter clock, then 64 state and LRCLK / SDOUT generator (2 x 74HC165+glue logic) will make I2S signal.
Will Anyone try? If I do, it will be from some month later.
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