Buffalo DAC (ESS Sabre 9008)

[MrMajestic]

Re: 192kHz S/PDIF

So, just finished testing a Buffalo with the updated comparator in place. I get solid lock at 24bit/192kHz S/PDIF.

Since I don't have a true 192kHz source, my test rig used a Metronome to upsample a 16/44.1 signal to 24/192 I2S, which was then fed through a WM8804 module to transmit the S/PDIF to the Buffalo.

Future Buffalos will use the new comparator.

Is this something I should be worried about on the last run of Buffalo's? Or is it only in certain cases?

 

[BrianDonegan]

Sounds awesome, so when are the new Buffalo boards going to be available again?

I am building now. It will be about four to five weeks. I am building a lot of them.

Also how about the Counterpoint?

Same as this morning... http://www.diyaudio.com/forums/showthread.php?postid=1646450#post1646450

On another side note, the USB receiver - what level is the I2S signal from it? 3.3V or 5V? I was looking at the PCM2707 datasheet and I couldn't find a clear answer on that so I'm wondering if you know.

I'll check. Since it is running of the USB 5V, I would think it is 5V but I will throw it on the scope and measure.

 

[steinh]

Trouble with hyperactive automute

Hi!
I have recently finished my Buffalo and I am very pleased with it's performance! But I have one issue; the automute function steps in between all tracks. And it has a short delay for it to disengage, that "kills" the opening of every track. Just the first half a second or so, but still very distracting. Anyone have a suggestion how to fix this?

Stein

 

[muizel]

Ps Metronome

When you use a Metronome with the Buffalo and Ivy. I think the best is to make a separate 7.5 volt ps for the Metronome ? Is that right and would a LM317 do the trick or need the Metronome a more sophisticated approach ?

Thanks René.

 

[fmak]

Re: Ps Metronome

When you use a Metronome with the Buffalo and Ivy. I think the best is to make a separate 7.5 volt ps for the Metronome ? Is that right and would a LM317 do the trick or need the Metronome a more sophisticated approach ?

Thanks René.

I have actually gone from powereing the Buffalo/Ivy with the TW supplies to powering all modules separately throuh ALW (Jung type) regulators. The sound goes from very acceptable to great transparency and clarity.

So, the better the PS, the better the result. Also try two transformers whichis what I usefor the Ivy and the Buffalo/other digital modules.

 

[muizel]

Re: Re: Ps Metronome

I have actually gone from powereing the Buffalo/Ivy with the TW supplies to powering all modules separately throuh ALW (Jung type) regulators. The sound goes from very acceptable to great transparency and clarity.

So, the better the PS, the better the result. Also try two transformers whichis what I usefor the Ivy and the Buffalo/other digital modules.

Thanks fmak,

Can you give me a link for the schematic of the PS you build ? that would be great

René.

 

[BrianDonegan]

So, the better the PS, the better the result.

This is the theory behind the new Placid power supply. It should be available by the time the next round of Buffalo DACs starts shipping.

 

[mikelm]

My experience also confirms that the theory is correct . . .

 

[Russ White]

Re: Ps Metronome

When you use a Metronome with the Buffalo and Ivy. I think the best is to make a separate 7.5 volt ps for the Metronome ? Is that right and would a LM317 do the trick or need the Metronome a more sophisticated approach ?

Thanks Ren�.

Just curious why put a metronome in front of a Buffalo?

Only reason I can think of would be to convert 48fs I2S to 64fs I2S. Is that what you are doing?

In any case I would use the same supply as you use for VD on the buffalo. It should work just fine.

Cheers!
Russ

 

[muizel]

Re: Re: Ps Metronome

Just curious why put a metronome in front of a Buffalo?

Only reason I can think of would be to convert 48fs I2S to 64fs I2S. Is that what you are doing?

In any case I would use the same supply as you use for VD on the buffalo. It should work just fine.

Cheers!
Russ

Hi Russ,

I have a CDM2 PRO drive waiting over here and want to connect the Buffalo through i2s that's all .

Since you recommend (manual of metronome) a 7.5 volt dc ps for the metronome my first idea was to make a separate ps for it.

Cheers René.

 

[langtuhanoi]

I use Bluray Pioneer player with HDMI port.
Is there HDMI device what split audio signal and video signal (HDMI audio > I2S audio) and video signal to projector (HDMI video > HDMI video)
Thank

 

[mikelm]

this is the closest I have seen to what you look for

http://www.gefen.com/kvm/dproduct.jsp?prod_id=3939

 

[fmak]

Re: Re: Re: Ps Metronome

Thanks fmak,

Can you give me a link for the schematic of the PS you build ? that would be great

René.

Search for ALW regulator in main forum. Not simple to make up and you need to test your prototype for stability etc. But I make laods of them and use for everything. The pcb mounting holes are 'stupid'.

good for 0.5A and vbery low noise (O(10 uV) 1Mhz bandwidth) with right opamp.

 

[fmak]

This is the theory behind the new Placid power supply. It should be available by the time the next round of Buffalo DACs starts shipping.

I'd like to try this. However, the performance of the reulators on board the Buffalo and Ivy also matters and can be improved.

Russ, any mods or alternative here? LT makes some 40 uV 3.3V chips and I have used them to modify commercial equipment successfully

Fred

 

[BrianDonegan]

There are no regulators on the IVY.

 

[Russ White]

I have used them to modify commercial equipment successfully

Fred

I have spoken with Dustin about this at length and tested many theories.

While I encourage you to try whatever you are comfortable doing your self, I would absolutely not encourage people to go fiddling with the on board power local regulators. Nor do I have any suggestions for doing so.

Measurements and listening have indicated the single most critical power supply to be the analog supply. If I were going to do any fiddling it would be there, but what is there already is great. With placid coming one could possibly remove the opamp (not really easy at all) and use the shunt reg to supply 3.3V. Would it make a perceptible difference? I have no idea. But if you have to fiddle, that's the place I would go.

Cheers!
Russ

 

[mikelm]

fiddling & PSU noise

.
This is a diy site, everyone here is a fiddler, fiddling is what we do

In my experience reducing noise in supplies never fails to bring good audible effects. With the buffalo the changes are more subtle because it is pretty good from the beginning

I'm not sure how low noise placid is but I look forward to trying it.

I agree with Fmac's conclusion if every other potential noise source has been covered then the spot light will then fall on the buffalo board itself.

There are two areas there which draw my attention.

The regulators have already been mentioned, but the other slight concern I have is the small bypass capacitors across the 100uF on board caps.

I did some research on this area in spice a while back and found that if estimated lead or track inductances are included a small bypass cap sets up a tuned cct that "rings" at ultrasonic frequencies. This ringing is excited by the signals in the circuit and effectively adds noise.

This research plus my experience with listening has persuaded me to always use snubber resistors with bypass caps ( Perhaps 0.1 ohms with a 1uF cap ). These snubber resistors completely stop this ringing

Russ, did you consider this as an option when you designed the buffalo board and rule it out for some reason . . . or has it not been tried yet ?

cheers

mike

 

[Russ White]

Mike, those bigger lytics are the decoupling caps for the digital supply regs, a snubber would be of little use there as the only thing the regs drive directly are digital circuits.

There is only one small bypass cap at the critical AVCC pins.

At the AVCC pins you really only want a small capacitance because the supply is in a feedback loop, and you don't want he opamp driving a high capacitance. Its all actually very well thought out.

Feel free to try what you like. I am very pleased with it as it is.

The placid will be very very low noise. Basically it will be dominated by the noise of the opamp and the LED voltage reference which will be significantly attenuated by a filter. It also has very good PSRR and load regulation.

I don't have one in my hand yet to confirm it, but soon.

Cheers!
Riss

 

[LTK]

I agree with Russ, the supply for AVCC L&R makes a big difference, I've tried a few supplies to the VA socket for the onboard LM4562 which seems to be buffering the 3.3v for the AVCC and even that has an impact on the sound

Russ, I'd certainly try feeding the AVCC direct from the Placid, it should be very interesting IMHO

 

[DexterMorgan]

Hi,

When connecting the USB-board to the Buffalo DAC running I2S input, should SCK or DO be connected to D2? In the manual it says that 'serial data' should be connected to D2 ...

Dex