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Designing a practical ES9038 based eight channel DAC

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Brian and I have been thinking through some of the design and building challenges associated with a new 8 channel design.

We have come to the conclusion that we should be bringing some very direct questions to the people who are really wanting it so that we can reason about the various challenges and associated costs in terms of both material and complexity.

We will also want to gauge the actual interest in this design - and probably take pre-orders once it's finished so that we know how many to make in the first run.

Here are some of the immediate questions:

Input:

1 - What actual multi-channel source are you planning to use?
2 - Will PCM/DSD input be sufficient? Note anything else will likely require some sort of separate input module(s) - so be specific.

Output:
1 - What are your ideas around the physical layout and casing?
2 - Do you prefer individual output boards or a monolithic 8 channel board?
3 - Do you value absolute fidelity(floating - mercury type front end) or lower cost (gnd reffed IVY type front end)?
4 - Are you likely to need SE outputs?

Control:
1 - How do you anticipate controlling the DAC?
2 - Is on-board control important to you?

Note: This is a crucial topic.

Regulators:
1 - do you prefer a tight local PCB layout with on-board regs - or would you rather have the flexibility of Trident/AVCC style regulators?

Master Clock:
1 - do you prefer the optimal layout, performance, simplicity and reliability of a local best in class on-board master clock - or the flexibility and added complexity/cost of external clock sources or Rhea modules?

Note: I am strongly inclined to opt for the local clock unless I see a very compelling reason not to do so.

There are other questions that I am sure will come up in the course of discussion.

My current thinking on output modules is to make them individual channel modules that would be neatly wired using appropriate headers and balanced wiring to the DAC and channels summed there to suite the application. Those modules will be designed such that they will have XLR/RCA connectors on board for direct back panel mounting. I want to hear your thoughts in this regard.

Now is your chance! What sort of 8 channel DAC are you looking for?

Cheers!
Russ
 
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input
1. Pure Music source with crossovers for multiway speakers. Possibly 5.1 surround from DVD player.
2. For me yes PCM/DSD would be sufficient.
Output
1. It would be large enough for 8 XLR and 8 RCA outs. Direct panel mounting sounds great!
2. The point of multi-channel is more than just a stereo pair. It seems stereo pairs would be the most common expansion so perhaps consider it as 2* 4 ch solution boards that would allow optional jumping for 2 ch. Thus very high quality 4 ch, 6ch, or 8ch with two Mercury style boards.
3. Haven't heard the Mercury yet but suspect I will want it after I hear it at least for the four channel implementation. 8 ch moves toward audio interface territory or surround sound.
4. Yes unbalanced outputs are needed but could be off board ventus or ventus EZ.
regulation
1. For me why not place the best regs on the board. Playing with regs seems like more of an ultimate stereo tweek.
2. yes local clock

No ->Now is your chance ;^)
 
I am reponding as someone who has been doing MCH playback for a while and offering what I would like to have (and not had yet).

Input:

1 - What actual multi-channel source are you planning to use? PC-based server.
2 - Will PCM/DSD input be sufficient? Yes, but with capacity for higher sampling rates.
3 - Note anything else will likely require some sort of separate input module(s) - so be specific. Big point here. I would like to have USB, HDMI and LAN inputs.

Output:
1 - What are your ideas around the physical layout and casing? A 2R height that is large enough and foot-sure.
2 - Do you prefer individual output boards or a monolithic 8 channel board? The former but that increases cost and means multiconnectors which open up other issues.
3 - Do you value absolute fidelity(floating - mercury type front end) or lower cost (gnd reffed IVY type front end)? Above my pay grade.
4 - Are you likely to need SE outputs? Not likely.

Control:
1 - How do you anticipate controlling the DAC? Web interface but not critical.
2 - Is on-board control important to you? I do most of my control in the server so I see this as only for setup/maintenance.

Note: This is a crucial topic.

Regulators:
1 - do you prefer a tight local PCB layout with on-board regs - or would you rather have the flexibility of Trident/AVCC style regulators? No comment.

Master Clock:
1 - do you prefer the optimal layout, performance, simplicity and reliability of a local best in class on-board master clock - or the flexibility and added complexity/cost of external clock sources or Rhea modules? The former.


Any thoughts on volume control
 
Here it is:

Input
1 - What actual multi-channel source are you planning to use?
A modified miniSHARC board >> Cronus (providing clock for the miniSHARC and ASRC (Metronome) before it) >> DAC

2 - Will PCM/DSD input be sufficient?
Yes

Output:
1 - What are your ideas around the physical layout and casing?
Large box (3RU?) hosting everything; the DAC outputs connected to panel-mounted XLR connecters through wires (not board-mounted XLRs). DAC directly connected to Cronus (sitting on/under it). Since Cronus is connected to multiple boards with short wires (above), mounting the DAC on the rear panel would not be practical.

2 - Do you prefer individual output boards or a monolithic 8 channel board?
Individual boards (better placement flexibility, reparability, and upgradeability).

3 - Do you value absolute fidelity(floating - mercury type front end) or lower cost (gnd reffed IVY type front end)?
Mercury-type.

4 - Are you likely to need SE outputs?
No.

Control:

1 - How do you anticipate controlling the DAC?
No DAC controls: all done in miniSHARC and before it.

2 - Is on-board control important to you?
No (above)

Regulators:
1 - do you prefer a tight local PCB layout with on-board regs - or would you rather have the flexibility of Trident/AVCC style regulators?
Trident/AVCC-style regulators (upgradeability and reparability considerations, but no really strong opinion here).

Master Clock:
1 - do you prefer the optimal layout, performance, simplicity and reliability of a local best in class on-board master clock - or the flexibility and added complexity/cost of external clock sources or Rhea modules?

On-board master clock.

Eagerly anticipating this (already have pretty much everything else assembled/tested and collecting dust for a year or so)...

Thanks a lot!
 
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1 - What actual multi-channel source are you planning to use? minisharc, USB multichannel, nanoavr via 2 teleporters. So multichannel I2S switching is necessary. Essentially planning on replacing my AVR with the DAC.
2 - Will PCM/DSD input be sufficient? YES Note anything else will likely require some sort of separate input module(s) - so be specific. I2S multichannel switching.

Output:
1 - What are your ideas around the physical layout and casing? Like to fit in a 2U enclosure.
2 - Do you prefer individual output boards or a monolithic 8 channel board? Individual boards may give better flexibility on layout.
3 - Do you value absolute fidelity(floating - mercury type front end) or lower cost (gnd reffed IVY type front end)? Better Fidelity.
4 - Are you likely to need SE outputs? NO

Control:
1 - How do you anticipate controlling the DAC? With an Arduino
2 - Is on-board control important to you? Not Really. Due to the multiplicity of multichannel sources, I would like to use the DAC volume control.

1 - do you prefer a tight local PCB layout with on-board regs - or would you rather have the flexibility of Trident/AVCC style regulators? Not Sure.

1 - do you prefer the optimal layout, performance, simplicity and reliability of a local best in class on-board master clock - or the flexibility and added complexity/cost of external clock sources or Rhea modules? On-board clock is fine.

My current thinking on output modules is to make them individual channel modules that would be neatly wired using appropriate headers and balanced wiring to the DAC and channels summed there to suite the application. Those modules will be designed such that they will have XLR/RCA connectors on board for direct back panel mounting. I want to hear your thoughts in this regard. Would prefer to use panel mount connectors. I generally wire from the board to the back panel even when on board connectors are provided.


As far as I am concerned you can take your time since I have quite a backlog of projects. Need to save up some money also since in won't be inexpensive.
 
Immediate Answers:

Input:

1 - What actual multi-channel source are you planning to use?

Either 8-channel USB to I2S or AVB to I2S

2 - Will PCM/DSD input be sufficient? Note anything else will likely require some sort of separate input module(s) - so be specific.

YES

Output:
1 - What are your ideas around the physical layout and casing?
2 - Do you prefer individual output boards or a monolithic 8 channel board?

DAC in middle - individual stackable boards on left and right sides.

3 - Do you value absolute fidelity(floating - mercury type front end) or lower cost (gnd reffed IVY type front end)?

absolute fidelity

4 - Are you likely to need SE outputs?

Not usually, but possibly in some builds I do. Good if it was an option but omitted by default to keep cost down

Control:
1 - How do you anticipate controlling the DAC?

Arduino via I2C interface - onboard isolator option for I2C, RESET, and GPIO pins would be wonderful!

2 - Is on-board control important to you? NO

Regulators:
1 - do you prefer a tight local PCB layout with on-board regs - or would you rather have the flexibility of Trident/AVCC style regulators?

Trident/AVCC style regulators

Master Clock:
1 - do you prefer the optimal layout, performance, simplicity and reliability of a local best in class on-board master clock - or the flexibility and added complexity/cost of external clock sources or Rhea modules?

Local clock with option for external (like current board)

My current thinking on output modules is to make them individual channel modules that would be neatly wired using appropriate headers and balanced wiring to the DAC and channels summed there to suite the application. Those modules will be designed such that they will have XLR/RCA connectors on board for direct back panel mounting. I want to hear your thoughts in this regard.

Sounds Good (SE and connectors optional to keep cost down tho, as I usually use neither in my builds)
 
Hi

I would be interested in a 8 channel DAC.
I am willing to pre-order

I will be using it from a Mini DSP (Open DDRC 88D)

Input:

1 - What actual multi-channel source are you planning to use?

MiniDSP or nanoDigi

2 - Will PCM/DSD input be sufficient? Note anything else will likely require some sort of separate input module(s) - so be specific.

YES

Output:
1 - What are your ideas around the physical layout and casing?

Would prefer XLR

2 - Do you prefer individual output boards or a monolithic 8 channel board?

monolithic 8 channel board

3 - Do you value absolute fidelity(floating - mercury type front end) or lower cost (gnd reffed IVY type front end)?

Will go with Lower cost

4 - Are you likely to need SE outputs?

Not likely if XLR is available

Control:
1 - How do you anticipate controlling the DAC?

Hopefully via jumpers or Arduino

2 - Is on-board control important to you?

Preferred

Regulators:
1 - do you prefer a tight local PCB layout with on-board regs - or would you rather have the flexibility of Trident/AVCC style regulators?

Trident/AVCC style regulators

Master Clock:
1 - do you prefer the optimal layout, performance, simplicity and reliability of a local best in class on-board master clock - or the flexibility and added complexity/cost of external clock sources or Rhea modules?

Don't want to tamper with Master Clock
 
I don't mind helping with prototyping. Sign me up for pre-order

Input:

1 - What actual multi-channel source are you planning to use? Minidsp DDRC-88D
2 - Will PCM/DSD input be sufficient? Note anything else will likely require some sort of separate input module(s) - so be specific. PCM will do

Output:
1 - What are your ideas around the physical layout and casing? Would love to get a cabinet with front & back panels already cutout.
2 - Do you prefer individual output boards or a monolithic 8 channel board? Monolithic
3 - Do you value absolute fidelity(floating - mercury type front end) or lower cost (gnd reffed IVY type front end)? Prefer fidelity unless it is substantially expensive
4 - Are you likely to need SE outputs? No

Control:
1 - How do you anticipate controlling the DAC? Don't mind jumpers/DIP switches, prefer an Arduino
2 - Is on-board control important to you? Yes

Note: This is a crucial topic.

Regulators:
1 - do you prefer a tight local PCB layout with on-board regs - or would you rather have the flexibility of Trident/AVCC style regulators? Onboard Regs

Master Clock:
1 - do you prefer the optimal layout, performance, simplicity and reliability of a local best in class on-board master clock - or the flexibility and added complexity/cost of external clock sources or Rhea modules? On board master clock
 
I'm very interested in this and am most likely going to join in on the pre-order GB. My participation depends on the final details that materialize for the board and output stage.

Input:

1 - What actual multi-channel source are you planning to use? 2x MiniDSP MiniSHARC's driving 6x + 2x channels
2 - Will PCM/DSD input be sufficient? Note anything else will likely require some sort of separate input module(s) - so be specific. This is good with me.

Output:
1 - What are your ideas around the physical layout and casing? I'm flexible since this is a new build
2 - Do you prefer individual output boards or a monolithic 8 channel board? Individual boards offer more layout flexibility, so that'd be my preference.
3 - Do you value absolute fidelity(floating - mercury type front end) or lower cost (gnd reffed IVY type front end)? I think it depends on how much more expensive a mercury-type front end would run versus the improvements. 2x as expensive with a subtle improvement, I'd prefer Ivy. 40-50% more expensive with a pronounced improvement, I'd prefer Mercury.
4 - Are you likely to need SE outputs? I plan on using balanced.

Control:
1 - How do you anticipate controlling the DAC? Arduino via i2c (HiFiDuino)
2 - Is on-board control important to you? Not needed.

Note: This is a crucial topic.

Regulators:
1 - do you prefer a tight local PCB layout with on-board regs - or would you rather have the flexibility of Trident/AVCC style regulators? I'll trust you guys on this one. I'll either feed the board with an ultra-low noise regulated source, or I'll use a trident solution you provide. One is a situation where the "power cleanup" happens on-board with the trident, and the other is before the power reaches the board. For me, it seems to be a similar outcome at roughly similar costs. Others may have more of an opinion if they're going to use this as an upgrade where they may already have an ultra-low-noise AVCC supply in their DAC case.

Master Clock:
1 - do you prefer the optimal layout, performance, simplicity and reliability of a local best in class on-board master clock - or the flexibility and added complexity/cost of external clock sources or Rhea modules? I'd prefer on-board with external as an option
 
Input:
1 - What actual multi-channel source are you planning to use? OPPO BDP-103 modded with VanityHD AES3 8 channels outputs goes into my BSS BLU-160 DSP. 8 channels of AES3 or SPDIF output from the BSS into this DAC
2 - Will PCM/DSD input be sufficient? Yes.
3 - Note anything else will likely require some sort of separate input module(s) - No

Output:
1 - What are your ideas around the physical layout and casing? None at the moment.
2 - Do you prefer individual output boards or a monolithic 8 channel board? Monolithic.
3 - Do you value absolute fidelity? Yes.
4 - Are you likely to need SE outputs? No.

Control:
1 - How do you anticipate controlling the DAC? I do not need to control it as far as I know. I control volume digitally before the dac. But it would be cool if a remote controled volume control could be added to this dac. But no deal-breaker for me.
2 - Is on-board control important to you? No.

Regulators:
1 - do you prefer a tight local PCB layout with on-board regs - or would you rather have the flexibility of Trident/AVCC style regulators? tight pcb, but with really really good implemented regulators, this is important

Master Clock:
1 - do you prefer the optimal layout, performance, simplicity and reliability of a local best in class on-board master clock - or the flexibility and added complexity/cost of external clock sources or Rhea modules? Local clock.


Fixed XLR outputs on the board is perfectly fine for me.
It would be really cool if DSP resources could be used for speaker correction EQ inside the DAC. Preferably with FIR-filters.
I also want to see mesurements of actual performance before ordering.
Pop-free turnon and turnoff is important.
Very high SNR is important for me.
Adjustable output-levels would be cool.
 
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My preferences

Input:
1 - What actual multi-channel source are you planning to use?
the DIYINHK multichannel USB XMOS board
2 - Will PCM/DSD input be sufficient?
yes

Output:
1 - What are your ideas around the physical layout and casing?
don't care
2 - Do you prefer individual output boards or a monolithic 8 channel board?
will be using my current 8 channels of IVY-IV boards
3 - Do you value absolute fidelity (floating - mercury type front end) or lower cost (gnd reffed IVY type front end)?
IVY
4 - Are you likely to need SE outputs?
yes

Control:
1 - How do you anticipate controlling the DAC?
I will write my own software
2 - Is on-board control important to you?
no

Note: This is a crucial topic.

Regulators:
1 - do you prefer a tight local PCB layout with on-board regs - or would you rather have the flexibility of Trident/AVCC style regulators?
flexible powering options

Master Clock:
1 - do you prefer the optimal layout, performance, simplicity and reliability of a local best in class on-board master clock - or the flexibility and added complexity/cost of external clock sources or Rhea modules?
on board local clock, with external clock as an option for sync playback
 
It seem most are wanting the best audio possible. Judging by how much better the I2s input sounds over SPDIF in two ch mode thanks to the amazing Hermes and Cronus it almost seems like the truly missing piece is an 8 ch usb to I2s incorporating isolation and reclocking and teleporter outputs.

It would provide the cleanest most pristine 32 bit 384 and dsd that could support the current Buffalo III-sePro in 2,4,6,8 channels, just buy more BIIIs. From the best a new a multi channel version of the DAC is really only offering a more compact and more cost effective entry point. Perhaps a BIII audio optimized for 4 channels would have wide appeal. Lowers cost and complexity for those needing only 4 channels. Can be combined with Buff III for 6 ch or doubled to provide 8. It may be unrealistic to want a full 8 ch ultimate audio and better suited to considering cost and ease of implementation when creating an all in one 8 ch DAC.


Does a USB to I2S 32 bit 384KHz device exist? I can't find one without adopting a unique control structure such as AVB or DANTE that requires smart receivers.
 
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