Twisted Pear Audio - Buffalo32S (ES9018 DAC)

[Muser]

Buffalo 32s Schematic

Hi guys:
I've been scouring this thread and tpa's support area for a picture of the 32s schematic. Can't find one. Is there one and I just missed it? I'm fetching information for the chief solder technician on my project and he wants to work off a schematic. Thanks for all of your kind tolerance of newbies here (when I learn more, I'll probably be deeply embarrassed by questions


Thanks in advance.
Larry

 

[Russ White]

Re: Buffalo 32s Schematic

Hi guys:
I've been scouring this thread and tpa's support area for a picture of the 32s schematic. Can't find one. Is there one and I just missed it? I'm fetching information for the chief solder technician on my project and he wants to work off a schematic. Thanks for all of your kind tolerance of newbies here (when I learn more, I'll probably be deeply embarrassed by questions


Thanks in advance.
Larry

Hi Larry,

There is no public schematic for now.

But if you are using the DAC as designed you will not need one at all. The manual should suffice. There is really nothing to do but solder some Terminal blocks and possibly cut few marked traces. All described in the manual.

I will likely post the schematic at some point, but for now there is some IP I want to protect for a little while.

Cheers!
Russ

 

[Muser]

Re: Buffalo 32s Schematic

Russ
OK, Russ. Thanks. You and Brian are certainly generous with your advice and time. Still makes me wonder if you have a full-time job or if you're independently wealthy and just doing TPA for kicks.

FWIW, my dad (the chief solder technician) is a master of precision and likes as much certainty as possible. I've had my kit for about a week and I'm getting antsy to put the DAC together, so I'm willing to do a lot to get that Solder Tech to work!

Not too much slave driving, but I'm willing to annoy him into action, too.
Larry

 

[AlanElsdon]

Re: Re: Roaming Buffalo now at home

Brian rocks. Thanks for the kind words.

You will lose less DNR using the Volumite than going through the attenuator and distortion will be less too. Channel matching will be much better.

Cheers!
Russ

I am sold - put an order in for one - but what exactly do you mean by DNR (Dynamic Range /Digital Noise Reduction / Do Not Resuscitate?).

 

[Spartacus]

Re: Re: Roaming Buffalo now at home

You will lose less DNR using the Volumite than going through the attenuator and distortion will be less too. Channel matching will be much better.

Cheers!
Russ

Hello Russ, have you measured this?

 

[Russ White]

Re: Re: Re: Roaming Buffalo now at home

Hello Russ, have you measured this?

No, I don't have an LSA to measure, but I know do know how LDRs work. And I can read the distortion charts . LDRs add a pretty hefty amount of distortion especially once you get over 1VRMS. I for one would not be willing to take a -50db THD+N distortion figure over a -117db THD+N. Even if were all 2nd order...

The DNR of the Buf32S at -60dbfs is 127db. If you run that clean signal through a set of interconnects and then some more passives (even the best quality) it will be less. Add to that the output impedance will be higher. So the best approach in my book, is to put nothing at all between the source and the amp. Then you will have the purest possibly signal and good line driving capability.

This is just my 2C. Some people may like the sound of the LSA, but I try to keep distortion to a minimum.

Cheers!
Russ

 

[Spartacus]

Re: Re: Re: Re: Roaming Buffalo now at home

No, I don't have an LSA to measure, but I know do know how LDRs work. And I can read the distortion charts . LDRs add a pretty hefty amount of distortion especially once you get over 1VRMS. I for one would not be willing to take a -50db THD+N distortion figure over a -117db THD+N. Even if were all 2nd order...

The DNR of the Buf32S at -60dbfs is 127db. If you run that clean signal through a set of interconnects and then some more passives (even the best quality) it will be less. Add to that the output impedance will be higher. So the best approach in my book, is to put nothing at all between the source and the amp. Then you will have the purest possibly signal and good line driving capability.

This is just my 2C. Some people may like the sound of the LSA, but I try to keep distortion to a minimum.

Cheers!
Russ

Thanks for the reply Russ. I'm using digital attenuation myself, and it sounds great. I'm also aware that LDR based attenuators have a distortion profile that varies with level.

As far as I can see, all attenuation methods have their strengths and weaknesses. Digital attenuation compromises the dynamic range of the DAC. Theoretically, if you have 60dB of digital attenuation, you are knocking 60dB off the DAC's performance, including PSRR.

But theory only tells one so much, as I'm sure you know. That's why I was curious to see a measurement to shed some more light on the issue, and I'd be interested to hear anyone's experience of comparing analog with digital attenuation via the Buffalo.

I'm absolutely delighted with the performance of my Buffalo. I've also found it to be very responsive to PSU mods, so it seems this is an area worth maximizing.

 

[Russ White]

Re: Re: Re: Re: Re: Roaming Buffalo now at home

As far as I can see, all attenuation methods have their strengths and weaknesses. Digital attenuation compromises the dynamic range of the DAC. Theoretically, if you have 60dB of digital attenuation, you are knocking 60dB off the DAC's performance, including PSRR.

This is not exactly correct, but there is only one point I will address. The DNR of the DAC is measured at -60dbfs. That's equivalent of applying 60db of attenuation. So that's 127db DNR at -60db attenuation for a full scale signal.

Also with the Buffalo32S there are more bits to shift downward.

I am very happy you enjoy your Buffalo.

Cheers!
Russ

 

[mikelm]

well, I have both LDR & volumite in my system.

My analogue control is 2.2K ohm Caddock TF020 in series with an LDR shunt ( but I think series & shunt LDR's would also be excellent ). The low impedance keeps distortion down and these controls are build onto input of my amps so I have no leads with attenuated signals on them.

having tried many options I would now not consider using any other analogue volume control but having said this I have taken extreme measures to ensure that the LED element has a silent supply and I know from experience that these LED/ LDR controls do need this to get the very best from them.

What I have now is clearly better that any other analogue control I have tried including TVC's ( although I would suspect that a stepped potentiometer with TF020's or texas bulk foils would be excellent if I could afford it )

I have compared using the LDR & volumite with the other one turn full up and my conclusion was that volumite is excellent as long as you do not have too much gain in ur system.

it's a pity that DVD's are recorded quieter than CD's because the difference makes it harder to set the system gain to an opimum.

If I was just playing music I would simply reduce the gain of my amp to 10 - 15 and I think volumite would be fine but with my system as it is now I prefer the sound of the LDR's.

compared to other volume controls volumite might be a clear winner in all circumstances but I have not made that comparison.

mike

 

[Russ White]

Mike you might want to simply reduce the output swing of the DAC. Is it an original Buffalo or a Buffalo32S?

 

[Spartacus]

Re: Re: Re: Re: Re: Re: Roaming Buffalo now at home

This is not exactly correct, but there is only one point I will address.

The DNR of the DAC is measured at -60dbsfs. That's equivalent of applying 60db of attenuation. So that's 127db DNR at -60db attenuation for a full scale signal.

Could you expand on why it is not correct? I'm aware that the DNR of the Buffalo is exceptional - I have all the figures in the data sheet.

I'm more concerned with supply noise finding it's way through into the signal. Again, the greater the digital attenuation, the more damaging any supply related noise will be.

 

[mikelm]

edited out of existance

 

[mikelm]

Mike you might want to simply reduce the output swing of the DAC. Is it an original Buffalo or a Buffalo32S?

then I would have to change it back when I was playing a DVD

I think a more ideal arrangement would be a higher output from the DAC ( I think I remember you commenting that this sounded good ) and less overall gain in the amp.

One day I might try and LDR or switchable gain resistor in my amp.

This would make my analogue control redundant and give me ideal conditions for volumite

 

[Russ White]

Re: Re: Re: Re: Re: Re: Re: Roaming Buffalo now at home

Could you expand on why it is not correct? I'm aware that the DNR of the Buffalo is exceptional - I have all the figures in the data sheet.

I'm more concerned with supply noise finding it's way through into the signal. Again, the greater the digital attenuation, the more damaging any supply related noise will be.

This is where you can see the beauty of fully differential signals. Even if there is some (very tiny) ripple on AVCC it will be common mode, and very effectively canceled by the fully differential I/V stage. This is especially true for the Buffalo32S.

So what you need to look at is the common mode and power supply rejection of the I/V stage.

Cheers!
Russ

 

[Spartacus]

Re: Re: Re: Re: Re: Re: Re: Re: Roaming Buffalo now at home

This is where you can see the beauty of fully differential signals. Even if there is some (very tiny) ripple on AVCC it will be common mode, and very effectively canceled by the fully differential I/V stage. This is especially true for the Buffalo32S.

So what you need to look at is the common mode and power supply rejection of the I/V stage.

Cheers!
Russ

Sure, the IVY has good CMRR. But still, digital attenuation is not a free lunch - it does have negative effects that need to be addressed. How much of an effect will depend on the system as a whole. A passive attenuator will not have these issues (obviously they have other issues), and this is where I feel a measurement will be the telling arbiter of the pros and cons of each method.

 

[mikelm]

Re: Re: Re: Re: Re: Re: Re: Re: Re: Roaming Buffalo now at home

Sure, the IVY has good CMRR. But still, digital attenuation is not a free lunch - it does have negative effects that need to be addressed. . . . and this is where I feel a measurement will be the telling arbiter of the pros and cons of each method.

If what Russ says is true and the DAC's noise is substantially cancelled out and they have 32 bits to play with then it may be pretty close to a free lunch.

I'm happy to trust my ears but I appreciate that this is not useful to anyone else - for all you know i could have the worst hifi on the planet . . . and think it's the best . . . hehe

 

[Spartacus]

Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: Roaming Buffalo now at home

If what Russ says is true and the DAC's noise is substantially cancelled out and they have 32 bits to play with then it may be pretty close to a free lunch.

For me, this is about enquiry and understanding, and has nothing to do with who's is best and all that nonsense. Like everyone else, I just want to build the best DAC I can, and I'm grateful to anyone who can help .... and maybe I can help some in return. I'm happy to hear any clarification anyone can give on the issue.

Getting back to PSRR, I'm happy to accept that an IVY will help the DAC's PSRR. But two points:

1) not everyone has an IVY,

2) even with an IVY, the Buffalo's PSRR is not infinite - plenty of people with IVYs have done PSU mods to their Buffalos and reported significant gains in sound quality.

If you accept point 2), then it follows that worsening the DAC's overall PSRR via digital attenuation could well have a negative effect on sound quality.

Maybe, maybe not, but I don't think it's safe to assume that because it's digital, it's perfect.

P.S. I really enjoy reading about your experiences Mike, as well as those of others, so keep it coming!

 

[Russ White]

Hi Spartacus,

I understand your pursuit, and don't fault your logic, and I applaud your curiosity.

A couple of key points:

1) Buffalo != Buffalo32S. Besides using a different DAC (ESS9018 vs ES9008) they are substantially different circuits and layouts.

2) The I/V stage in the Buffalo32S has some secret sauce which makes it even more effective than the older IVY at CMRR and PSRR. This is the reason I will not make the schematics public for a while.

Also people 'tend' to think a mod makes things better, its all about expectations. Now I am not saying that is wrong, because musical enjoyment is as much emotional as sensory. I have learned not to expect people to always have a logical approach to it, especially myself .

Bottom line, do exactly what gets you the most pleasure from the DAC. Experiment, and have fun by all means.

The same thing goes for what comes after the DAC. There are so many variables there. Use what brings you pleasure. I have given my opinion based on personal experience.

Cheers!
Russ

 

[jkeny]

Leo, has already reported (on AOS) that even with the new Buffalo32 there is an immediate improvement when using Paul Hynes shunt regs so I think the quality of the PS is still important, no?

As was stated to me recently - it's always easier to remove noise from a good quality initial PS than from a lesser initial PS!

 

[AlanElsdon]

Roaming Buffalo

I will wait for the Volumite to arrive and then compare it against the LSA in my system. I have to say that out of all the pre-amps I have had the simplest have been the best (TVC / Pass B1 / LSA) - however if it is possible to run the Buffalo 32 directly into my amps and reduce the number of interfaces then it must be a good thing.

I will report in a few weeks time once I have the Volumite working in the system - this will of course be purely subjective.

Alan