Regarding the offer of kits in return for help. Maybe not framed the right way to promote what you want: Transactional leadership - Wikipedia
Or, perhaps a more enjoyable and entertaining way to learn: 282: How to Motivate People, with Dan Ariely
Or, perhaps a more enjoyable and entertaining way to learn: 282: How to Motivate People, with Dan Ariely
Thanks a lot for the heads-up Mark: I really should clarify my intent.
I'm not asking for help. If people want to help, they will do that no matter what, as many do that already, you being first among them. Instead, I'm just trying to make it easier for people to feel "concerned" by the project, even though it's using a very expensive and complex DAC chip that otherwise would be out of reach for your typical DIYer. I've read several comments along these lines on other threads, and all I'm trying to do is to lower the barrier to entry.
For many DIYers on this site, the cost of a kit would be prohibitive, and I am worried that this fact alone might turn many people off. Instead, if the availability of a handful of free kits could allow some of us to participate in a project that would otherwise be out of reach, we would all benefit from the increased level of engagement. But this should not be interpreted as a form of quid pro quo or transactional leadership, which would be grossly disrespectful. Rather, it's just a way to acknowledge the very high risk factors attached to the overall project, and a way to foster participation by taking financial considerations out of the equation for the ones that can afford them the least.
There is also a very selfish motivation on my part: if I am the only end-user for this system, I have very little incentive to complete the project within any reasonable amount of time, because I'm already getting a lot out of it through the sheer amount of learning that I am deriving from it. But if there is a dozen readers who are eagerly waiting for a nice piece of kit, this creates an external forcing function that will keep me honest and engaged. By the same token, by making the kits available for free and by expecting nothing else in return (other than a basic level of feedback), I keep this external pressure as healthy as it can be. In other words, nobody can reasonably complain that the kits are taking too long to become available. Furthermore, this expectation of a kit coming down the pipe should create some level of project ownership that will motivate people to make meaningful contributions, not just at the engineering level, but also and maybe more importantly at product management and project management levels.
This is a perfect example of a self-fulfilling prophecy, which can be a very powerful force.
My grand-father used to say something along these lines: "From each according to his ability, to each according to his needs." This is rather funny, because he was a very politically conservative guy, yet this slogan was popularised by Karl Marx (Cf. Wikipedia). And while it was later used in some morally-corrupt ways, I still believe that it holds true in many situations. The present one might be one of them.
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Hi, so what's your current schematic you're working on ? This topic needs pictures
Schematic for which component of the system? There are quite a few...
I'm more focused on the DAC chip
Got it!
Well, I hope to have a schematic for the DAC board within two to three weeks. It will be very close to the schematic for the daughterboard of the AKM evaluation board (AKD4499-B). All schematics will be provided with detailed BOMs. Unfortunately, I cannot share the original schematics, but you can get them by contacting AKM's sales department.
I hope to have schematics for the Plate PSU board and the DAC PSU board within the same timeframe as well. You will need both PSU boards to power the DAC board.
Schematics for the XLR board will come right after, followed by schematics for the development board. Schematics for the MCU board (the one with the STM32H743) will take quite a bit more time, because this is a really complex chip. But I hope to be done with all that before the end of October.
You can find a synoptic for the power supply architecture on this post.
All schematics are being developed using Altium CircuitStudio. The original project files will be added to a GitHub repository sometime next week. Everything is licensed under CC BY 4.0.
I hope this helps.
Ismael
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You probably want to get a copy of the AK4499 evaluation board manual, which is included with the eval boards, or can possibly be obtained by asking the AKM distributor for your geographic area. Otherwise, it looks like AKM hasn't posted that document on their website. Don't know why that is.
The document that comes with the eval boards is slightly newer than the one I have from the distributor. A page was added showing LF distortion vs cap values for the Reference Voltage bias circuitry.
EDIT: Although information in the eval board manual is mostly accurate, it looks like a few small revisions in the eval board circuitry didn't make it into the version of the manuals currently being shipped.
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So, people making requests can give their reasons for wanting one in private?
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I already have a 117 pages AK4499_myakm.pdf and a brief 10 pages AK4499EQ.pdf. The first one have a recommanded external circuits (fig. 81). I'll wait for what you will post in a few time, thanks!
I'm looking for my personal project, combo this awesome chip with my DSP
These are not enough. You'll need the evaluation board's manual if you want to understand how to properly use this converter.
But our schematics should help as well.
Integrating this with a DSP should be really cool. Which DSP chip are you using? We're going to use the AM5728 Sitara.
Yes. I am not looking for any kind of public endorsement.
Thanks a lot for helping me clarify this.
Mark, I must say that I love your attention to details.
OK it's the one I don't have, you're right it's not public (yet?)
It's a combo, 1701 for crossover/volume etc and 1452 for FIR. Just a little board with the add-on for FIR, but I can get the i2s outs and stack 2 stereo DACs or one 4ch DAC under it.
It's just a huuuge project for a little guy like me
OK it's the one I don't have, you're right it's not public (yet?)
It's a combo, 1701 for crossover/volume etc and 1452 for FIR. Just a little board with the add-on for FIR, but I can get the i2s outs and stack 2 stereo DACs or one 4ch DAC under it.
It's just a huuuge project for a little guy like me
This is an awesome project!
I sent you a PM.
OK it's the one I don't have, you're right it's not public (yet?)
It's a combo, 1701 for crossover/volume etc and 1452 for FIR. Just a little board with the add-on for FIR, but I can get the i2s outs and stack 2 stereo DACs or one 4ch DAC under it.
It's just a huuuge project for a little guy like me
For your project, you might be able to use our DAC board as some kind of "DAC on Module" (DAM) or "Converter on Module" (CAM). It will have the AK4499 with the big capacitors and the I-V stage. Nothing else. It will be quite small though.
Going back about 10 pages there was some discussion regarding power supplies. I wanted to throw a reference in to the mix - Simple Isolated +/-15V Split Rail
– QuantAsylum - this page shows a design for an isolated +/-15V from 5V in that could be used for the opamp supplies. May wish to explore different LDOs though. The low power handling would mean a bit of a change of the topology currently proposed (probably won't have enough power to drive the opamps as well as VREF regulator and MVDD). But the isolation may be worthwhile.
Another separate observation on clicking back through the thread is that the OTOBUS pin out looks to have very few ground connections. For all digital signal wires there should be an adjacent pin connected to ground. For signal integrity and EMI it is important to have a return path as close possible to the signal wire, particularly for fast (short rise time) signals. This ensures that the loop area of the signal path is minimised.
Chris
Chris
– QuantAsylum - this page shows a design for an isolated +/-15V from 5V in that could be used for the opamp supplies. May wish to explore different LDOs though. The low power handling would mean a bit of a change of the topology currently proposed (probably won't have enough power to drive the opamps as well as VREF regulator and MVDD). But the isolation may be worthwhile.
Another separate observation on clicking back through the thread is that the OTOBUS pin out looks to have very few ground connections. For all digital signal wires there should be an adjacent pin connected to ground. For signal integrity and EMI it is important to have a return path as close possible to the signal wire, particularly for fast (short rise time) signals. This ensures that the loop area of the signal path is minimised.
Chris
Chris
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