Hello Folks,

I have the great privilege to design some pretty cool gear for myself and for people who like me enjoy great music and enjoy the DIY aspect. I get to do what I do because you people like the result.

Lets make a few things clear. I am not an electrical engineer, but I know my way around. I am not sure I am even an "audiophile" because I think that term has been somewhat bastardized. I am a naturally inquisitive and curious person who loves music and challenges.

So that's enough about me. What am I taking the time to post about here...

I have been thinking a great deal bout the direction to take for the ES9018 DIY edition board.

There are some details of execution which leave me perplexed as to which road to choose.

Some people want (or think they want) flexibility, but the honest truth is that the very best design is not going to be all that "flexible". The reason is that certain parasitic properties of PCB design will start to dominate if you leave too many options open. I don't feel like I am doing people a service if I give them a flexible pile of junk. I have been conversing with some of my EE friends and there seems like some things you just can't compromise on and retain a good degree of measurable success. Especially regarding RF and EMI.

What spawned all of this critical thinking? Well honestly a very brutally honest email from a comrade name Per. :) I won't mention his full name because I am not sure he wants me to. In any case he made me realize just how little I know about a few things. Lets just say I know more now, but I am still a journeyman.

Here are some thoughts:

1) Would you really want to pipe in all your critical power supplies and add all the wire and/or trace inductance and possibly EMI? Or do you want well thought out local regulators with extremely short load lines? I will expound more on this later.

2) In our listening tests and measurements it has been proven that the link between the DAC and the I/V stage needs to be EXTREMELY short to get the best possible DNR. This means that active I/V conversion after the DAC really needs to be on the same PCB to be optimal for both supply (especially GND) reasons and because of the length of the copper going to the I/V stage. This is not to say external I/V does not work nor sound great, it just does not prove optimal from an engineering standpoint.

There are more points to come, but I want to get some feedback on these two first.

Lets make this an open dialog. I want to design what you people want, but I also want to make it the "best" practical implementation at the same time. There are some aspects of those two goals that conflict. Some of you (there is no offense meant here to you) think you know what you want. But if you had as much experience as me in this area I think you might change your mind. So please let this dialog be instructive to all involved.

So lets hear it. What do you want? While this is my project, I consider myself always a student. If I need to know something you know I will listen and learn. This project is not just about me anyway. It is about you too!

It is important to me to produce quality work, so I am trying to focus my efforts on what produces the best possible result while still getting you what you "want". I am leaning toward an updated Buffalo32S versus a "tweakers" type board, but that is me and what I want, not necessarily you. The reason I want this is that I have learned from experience that the way to performance is optimal layout. Optimal layout requires clear design goals and that does not usually work well with open ended options.

Think of it this way. The best time to tweak a design is before its laid out. Now is when you should speak up and let me know what YOU want. :)

Now I hear all of you who say "But Russ! I really want to try supply X and Output stage Y." OK, I can produce a board for you, but what would be on it? And are you willing to potentially compromise the final result? Or would you rather participate in designing what you really want from the outset? In this way no "tweaking" is required. You would already have what you want. Just enjoy the music. :)

Enough rambling. Lets here from you!

Cheers!
Russ

Edited by user Thursday, July 22, 2010 8:02:03 AM(UTC)  | Reason: Not specified

Perhaps a single board for standard and tweaker with vias/jumpers for power and output stage. The tweaker can be sold with the poewer and i/v unpopulated, and the standard can be tweaked by removing the jumpers.

You should really take a listen to the Buff32 with the built in audio stage. Its quite different and much more envolving(IMO)than the Buff24/IVY combo.
I would spend my efforts with the PS's. Personally I am waiting for the Placid, I do not know enough to design my own PS

It is all very difficult... another solution could be to offer a selection of Buff32s boards but with different output stages built in - like the current one. I can think of at least two. Maybe the current one and another one with an improved discrete design like the CounterPoint - I was thinking this maybe very good?

This allows people flexibility of choice, I guess there could be others?

Also a choice on the main power supplies seems like a good option, but with the Placid on the way, that option seems covered.

Just my two pennies worth...

Request:
1)Please do a real galvanic isolation on all signal inputs (I2S and SPDIF)!
Use proper transformers or optocouplers with the required bandwith.
I hate what groundloops and ground noise can do to systems performance!

2)I like to use Blackgates, so through hole possibility on onboard caps is wanted.

Keep up the good stuff!!

Cheers,
Tom

Edited by user Tuesday, August 18, 2009 12:23:39 PM(UTC)  | Reason: Not specified

I'd add that it would be nice if the next iteration used 21Ohm output resistors as default and for the headphone listeners there would be shorting jumpers. IMHO the majority of builders intend to use the Buffalo as a DAC/preamplifier into power/headphone amplifier and for these the cutting procedure is useless nuisance.

From my experience with other DAC's the more notable improvements were always attained by improving the quality (and number) of the power supplies.
My number one wish would therefore be the option to use different on-board regulators and bypass caps.
Well, I would also like to hear the B32S V2 with separate ground planes for the left and right channels.

Russ,

This isn't going to help, but one of these days (months, years) I will get round to finishing the design for Quoll - my discrete IV circuit study that triggered the ideas for the cap mod of IVY.

The benefit that it will offer over the chip used in IVY is that the compensation will be tweaked for this circuit configuration, and all the poles pulled out to the virtual earth point, which can't be done with the off the shelf monolithic circuit. The downside is that discrete circuits never get as good matching of devices as monolithics.

As 6 months have gone by without progress, nobody should hold their breath.

PD

just an acknowledgment here that I heard all of you.

I will have some design news coming.

Hi Russ and Brian,

Re post from Ejaouen

"Hi
About this new buffalo board :
I would like it to be 8 channel capable "build in" so NO "buffalo stereo" this time.
It could be nice to have the 8 channel voltage out possibility.
Concerning your points :
1) I think well thought out (by you) included LDO regs and short traces powersupply would be the best performing and easiest solution by far. I do not want to tinker with powersupply.
2) concerning output stage I would really love "build in" simplistic discrete I/V stage for the 8 channels
or 8 channels of IVY
or at least access to the ESS chip 8 channel voltage outputs.

In fact I do not need to tinker I just want the best "stock" performance (spec numbers : DNR, SNR) and 8 channels of discrete I/V outputs.

Thanks a lot"

I would like to concur with this. My true interest lies with speaker design and to that end my stereo system revolves around single ended usage. How ever the information that my "OLD brain" has gleed from your site and work has been very much enlightening to me.

My next venture into speaker projects (The wife will only stand for so many speakers in our tiny lounge room) will be for the home theater side of things and my current thinking is along the lines of some sort of source / control (probably PC bassed) feeding a buffalo via 2 to 4 separate inputs which will have the 8 outputs (single ended and ballanced) to feed what ever amps and speakers I intend to try. (Usually have to follow someone elses designs "thankyou Zaph and Tony Gee" until I feel brave enough to have a go myself).

Balanced out to 7 Sympatico's by each speaker and single ended to the sub would I think be very impresive with the speakers matched for the room and would give the builder a greater degree of flexability.

Anyway Just my thoughts.

Regards

Ian