CSR / SaviAudio Bluetooth jitter
Hi,
I'm wondering whether to buy a bluetooth (CSR8670 or similar) with spdif and feed that into a receiver, say WM8805, AK4113 etc, to get a low-ish jitter I2S (50ps), or buy a bluetooth with I2S firmware and feed that directly to the DAC.
While I Understand phase noise and jitter, I'm not clear on the information given in CSR datasheets about jitter. For example the datasheet on CSRA64215 (APTX LL, I2S out) has only a few mentions of jitter in 107 pages:
1) Spec for PCM timing: PCM_CLK jitter - 48 MHz DDS generation - 21 ns pk-pk
2) Less relevant are specs for an external oscillator : Edge jitter (at zero crossing) - 10 ps rms(b)
So does anyone know if using an spdif+receiver will produce less jitter than I2S direct with CSR chips? 21ns seems huge so I'm guessing spdif is the way to go.
Thanks
EDIT - to complicate matters, I've just found a SaviAudio SA9910 BT4.2 96/24 I2S out device. Hunting for a datasheet...
Hi,
I'm wondering whether to buy a bluetooth (CSR8670 or similar) with spdif and feed that into a receiver, say WM8805, AK4113 etc, to get a low-ish jitter I2S (50ps), or buy a bluetooth with I2S firmware and feed that directly to the DAC.
While I Understand phase noise and jitter, I'm not clear on the information given in CSR datasheets about jitter. For example the datasheet on CSRA64215 (APTX LL, I2S out) has only a few mentions of jitter in 107 pages:
1) Spec for PCM timing: PCM_CLK jitter - 48 MHz DDS generation - 21 ns pk-pk
2) Less relevant are specs for an external oscillator : Edge jitter (at zero crossing) - 10 ps rms(b)
So does anyone know if using an spdif+receiver will produce less jitter than I2S direct with CSR chips? 21ns seems huge so I'm guessing spdif is the way to go.
Thanks
EDIT - to complicate matters, I've just found a SaviAudio SA9910 BT4.2 96/24 I2S out device. Hunting for a datasheet...
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Bluetooth Digital Optical Transmitter Receiver AC1070\
I have found this item to sound particularly good, if you are keen you could add a Coax Spdif output.
I find it great for when I have guests, I get them to BT connect their phones and be the DJ's, I get to hear different music, they get to hear a good system, win win.
Dan.
I have found this item to sound particularly good, if you are keen you could add a Coax Spdif output.
I find it great for when I have guests, I get them to BT connect their phones and be the DJ's, I get to hear different music, they get to hear a good system, win win.
Dan.
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well, my internet wizardry managed to obtain a datasheet for savitech sa9910 module and it is based on sa9620 - datasheet says "the I2S interface setting at slave mode and supply standard format 44.1KHz, 48KHz, 96KHz, 32-bit". As a slave, it'll want something an ESS DAC, maybe I'll try a ES9018k2m since they are practically free these days.
There are no jitter specs and it is not clear if it upsamples or requires an LHDC transmitter to upsample (Huawei seems to be the only one atm). The module looks to be a standard 30 pin 22x15 pcb so I guess it's worth a try at an exorbitant $8.
There are no jitter specs and it is not clear if it upsamples or requires an LHDC transmitter to upsample (Huawei seems to be the only one atm). The module looks to be a standard 30 pin 22x15 pcb so I guess it's worth a try at an exorbitant $8.
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So I tried out a Qualcomm QC3008 (BT5.0, APTX, 80mhz dsp), and their CSR8670 (BT4.2, APTX, 80MHz dsp). Both are I2S out into a ES9018k2m and I can't hear any difference. That's not to say there aren't any differences, but simply the BT+DAC combo doesn't produce audible differences for me.
Modifying the DAC has changed the sound but switching BT modules doesn't. I reckon I need to try a DAC that is more sensitive to jitter - I've got a "classic" AD1852 I can try, if I can work out how to create a MCLK (11.2896Mhz) for it. Anybody have any ideas about creating a MCLK for a BT module without reclocking all the I2S lines? I don't want to reclock in any way because this would change the BT modules' jitter, and that's what I'm curious about.
I haven't tried the SA9910 yet - the adapter pcb didn't quite fit the module pcb so I'm hunting for a correct adapter pcb.
Modifying the DAC has changed the sound but switching BT modules doesn't. I reckon I need to try a DAC that is more sensitive to jitter - I've got a "classic" AD1852 I can try, if I can work out how to create a MCLK (11.2896Mhz) for it. Anybody have any ideas about creating a MCLK for a BT module without reclocking all the I2S lines? I don't want to reclock in any way because this would change the BT modules' jitter, and that's what I'm curious about.
I haven't tried the SA9910 yet - the adapter pcb didn't quite fit the module pcb so I'm hunting for a correct adapter pcb.
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