As all of you may know already, the great ES9018 DAC chip on Buffalo DAC is doing this partially as usual. The Buffalo DAC default setting employs "Over sampling mode ( 8x )". Hence, 44.1 k 16 bit materials are internally re-sampled to 352.8 kHz.
For a true 352.8 kHz /24 bit file, internal sampling rate is 352.8 kHz x 8 = 2.8224 MHz!
Hi Bunpei,
I think you are confusing two features. If you turn off the OSF the chip does work better if you input PCM at 8X the original sample rate. Here ESS is assuming you likely used an external digital OSF that outputs at 8X FS. The OSF rate and the final sample rate are not exactly the same.
In the best performance mode, all sample rates in are internally asynchronously re-sampled to rate that is independent of the source sample rate. That rate is set by the master clock alone.
It very true that prior to jitter reduction the supplied sample rate is run through the 8X OSF .
So it is true to say that ay one point the sample rate is 8X FS, after that it is even higher.
I think you are confusing two features. If you turn off the OSF the chip does work better if you input PCM at 8X the original sample rate. Here ESS is assuming you likely used an external digital OSF that outputs at 8X FS. The OSF rate and the final sample rate are not exactly the same.
In the best performance mode, all sample rates in are internally asynchronously re-sampled to rate that is independent of the source sample rate. That rate is set by the master clock alone.
It very true that prior to jitter reduction the supplied sample rate is run through the 8X OSF .
So it is true to say that ay one point the sample rate is 8X FS, after that it is even higher.
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Set the correct register via I2C.
We do not recommend nor supply firmware for that configuration, but it is not at all hard to do.
We may consider providing firmware for that application if there is a big enough demand, but I caution that the performance of the DAC is very much compromised in my experience in this mode.
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In the case of SDTran192, its recent firmware has capability of outputting I2C commands to set ES9018 registers on Buffalo II. The firmware switches the oversampling filter mode file by file depending on its sampling rate. For 352.8 kHz/ 24 bit: No over sampling, and for other sampling rates: Over sampling.
Can the user choose manually between oversampling and NOS, regardless of the file's rate?
Is not that the same that the Buffalo II does? If input signal is the maximum allowable (352.8khz), then no resample is possible, so no resampling will happen. If input signal is lower, then it will upsample them by default, as you pointed out:
It would be very simple to give you firmware the switches between OSF and Non-OSF. It is just a matter if it makes sense to bother. I would never use the chip in Non-OSF mode.
Even Volumite could easily be made to do this.
Remember all this register does is bypass the very first section of digital processing. In the end unless you turn off the Jitter reduction (which would be foolish) it will be re-sampled in any case, just not filtered.
Cheers!
Russ
Even Volumite could easily be made to do this.
Remember all this register does is bypass the very first section of digital processing. In the end unless you turn off the Jitter reduction (which would be foolish) it will be re-sampled in any case, just not filtered.
Cheers!
Russ
To say exactly, they say on "Normal mode" the maximum (allowable) PCM sampling frequency is 500 kHz. That's why Russ says 384 kHz/ 32 bit can be one of goals on his "XMOS USB -> I2S" development.
In my case, I tried two methods for write and read values on registers on Buffalo DACs via I2C. On the both methods, you need to detach MCU device on the Buffalo DAC.
1. Using ESS Technology ES9018 Evaluation Board for this purpose.
The board has an USB interface chip that bridge PC and I2C on board.
We can use very good GUI-based software provided by ESS to read and write registers on ES9018. I cut some patterns on the Evaluation Board, added an switch and extended SCL & SDA lines to Buffalo DAC. With the help of the excellent GUI software, I could recognize the effect of changing register value in almost a real time manner after clicking a mouse on PC screen.
2. Connecting Arduino board to I2C pins on Buffalo DAC
You can know how to do this on this blog page very well.
H I F I D U I N O: Programming Buffalo DAC: Review of Arduino I2C
Bunpei
FWIW, you might try flipping DIP switch 3 off and listen for awhile. That changes the OS filter from fast to slow roll off. It seems to relax the sound a bit without losing detail and resolution -closer to the NOS sound.
Just got my Buffalo II up and running on Optima Red battery power with PH regs and Onetics OPTs last Saturday and it's still settling in so I can't comment on the absolute value of the fast vs slow sonics, but I like slow a lot so far. Its hard to turn off the music at night. The only other DAC that had that long term effect on me was my Altman Attraction DAC.
I will comment on the sonics of the BII so far -its killer. Many thanks Russ and Brian on the great kit.
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Hi all,
I just wanted to say that I am very impressed with the Buffalo II, I have one up and running with an output stage based on the 6n6p tube and Lundahl 1689 transformers and it really is very good. It is not optimized yet and I am planing to upgrade several parts but it is very musical, transparent and engaging as it is, I will post some pictures when I kind of organize the mess
To give you the perspective I have owned EAD DSP 7000 Mk3, Audio Synthesis DAX-2 (both of them had all grades of PCM63 made - K, K2,KY, Y, Korean and Japan made) and I am currently using and Exemplar 3910 as source. The Bufallo is not as good as the Exemplar yet, but I am working on it
I am just trying to encourage people who are not decided about it to try a DAC that is very good without a million hours and thousands of dollars in modding.
I think I posted the schematic I am using some posts earlier, if anyone is interested.
I just wanted to say that I am very impressed with the Buffalo II, I have one up and running with an output stage based on the 6n6p tube and Lundahl 1689 transformers and it really is very good. It is not optimized yet and I am planing to upgrade several parts but it is very musical, transparent and engaging as it is, I will post some pictures when I kind of organize the mess
To give you the perspective I have owned EAD DSP 7000 Mk3, Audio Synthesis DAX-2 (both of them had all grades of PCM63 made - K, K2,KY, Y, Korean and Japan made) and I am currently using and Exemplar 3910 as source. The Bufallo is not as good as the Exemplar yet, but I am working on it
I am just trying to encourage people who are not decided about it to try a DAC that is very good without a million hours and thousands of dollars in modding.
I think I posted the schematic I am using some posts earlier, if anyone is interested.
Please repost?
Thanks
Thanks
Hi all,
I just wanted to say that I am very impressed with the Buffalo II, I have one up and running with an output stage based on the 6n6p tube and Lundahl 1689 transformers and it really is very good. It is not optimized yet and I am planing to upgrade several parts but it is very musical, transparent and engaging as it is, I will post some pictures when I kind of organize the mess
To give you the perspective I have owned EAD DSP 7000 Mk3, Audio Synthesis DAX-2 (both of them had all grades of PCM63 made - K, K2,KY, Y, Korean and Japan made) and I am currently using and Exemplar 3910 as source. The Bufallo is not as good as the Exemplar yet, but I am working on it
I am just trying to encourage people who are not decided about it to try a DAC that is very good without a million hours and thousands of dollars in modding.
I think I posted the schematic I am using some posts earlier, if anyone is interested.
I just came across this tube output stage that someone is using and I was wondering if you guys might care to comment:
audio-talk :: View topic - Buffalo DAC output stage
Looks simple and effective, of course the transformer could be a different one
I suppose the last post is a reply to my post, so here is what I wrote then...Using Lundahls 1689PP though.
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