Debian Wheezy
I followed the directions over at Computer Audiophile to the letter, no re-sampling, and excellent sound.
I followed the directions over at Computer Audiophile to the letter, no re-sampling, and excellent sound.
The raspberry pi plays even better through i2s with it's bad clocks than through usb with use of a wave io.
Bbb through wave io sounds the same as pi through wave io.
I hope the cape is ready soon
Wave IO
What do you hear in the BBB sound output through USB that is undesirable? It sounds great to me, but I'm curious what kind of specific performance improvements should be expect through the i2s and Botic.
The raspberry pi plays even better through i2s with it's bad clocks than through usb with use of a wave io.
Bbb through wave io sounds the same as pi through wave io.
I hope the cape is ready soon
What do you hear in the BBB sound output through USB that is undesirable? It sounds great to me, but I'm curious what kind of specific performance improvements should be expect through the i2s and Botic.
Electromagnetic interference (EMI)
Less EMI generated by USB or SPDIF processing.
But, If you don't use Teleporter then some EMI will be generated by BBB (and gadgets connected to it), because it will be close to DAC. Also there will be ground loop issues in some configurations and also EMI from I2S/DSD connection that needs to be handled too.
If you use Teleporter, then possible ground loops and EMI from BBB are reduced, but LVDS communication will add some EMI and also some jitter.
So... it will be different and surely fun to play with.
It is not that usb through wave io is undesirable. The sound through i2s is a tad more transparant and dynamic.
So if I have a choice...........
Using the botic will probably bring even more transparancy because of the lower jitter.
I have almost finished the other big project (which many of you will likely want) - and this board is also nearly complete - I am just going over the details and making sure I have no mistakes (that I can see anyway). 
My goal is to order PCBs in the next 2 weeks. Some weeks my formal occupation keeps me way too busy!!!
My goal is to order PCBs in the next 2 weeks. Some weeks my formal occupation keeps me way too busy!!!
I think it's up to the software you are using on the bbb. The only thing that can be problematic is that it puts out 20 or 24 bit words while your chip can only handle 16bits.
I had this problem with my dddac, it cannot accept 16bit I2S output from a Philips cd-pro loader, it needs 24 bits.
Regards,
The ES9018 requires that stereo I2S samples are sent in the 64bit word. So the driver will be also written in this way.
But later the support for 32bit word length (16bit stereo) could be added.
Be aware that standard Botic cape as currently planned can support only 16, 32 or 64 bit frames. For 24bit (3 byte) output the clocks would need to have different frequencies (3*44100*x) and (3*48000*x).
But later the support for 32bit word length (16bit stereo) could be added.
Be aware that standard Botic cape as currently planned can support only 16, 32 or 64 bit frames. For 24bit (3 byte) output the clocks would need to have different frequencies (3*44100*x) and (3*48000*x).
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Thanks Miero,
So those of us using a 16bit chip such as the tda1541A will need to wait to see if the 32 bit (16bit stereo) is added in a subsequent release. Correct?
I think it will be worthwhile. As great as the buffalo is, there is quite a community here that are sticking with their vintage chips.
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