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|16th January 2009, 01:24 PM||#1|
Join Date: Dec 2007
NeoY2k's ESS Sabre DAC platform
Some of you already knew I was drawing boards for the ESS Sabre. And some of you wanted some. So here is all about this project!!!!
- DIY use?
In fact, I'm a sound engineer that studied electronics for 5 years before switching to sound... I'm not really experienced to say the truth. But I'm doing my best!
I'm creating a full system for how most sound engineers work now (at least in France): oscillating between live sound reinforcement, live recording, studio recording, field recording... So it's a platform of high performance converters / interconnections, that can also transmit over long distances, and where everything can be chained. Its center network part is the Dice from TC.
I took too long to release that DAC board... I'm going to work harder now. Had not much time unfortunately.
What does that mean?
What I'm making right now are prototypes. I'm not going to create a "diy" company. That means I won't have much boards to spare...
The other point being that, before selling these boards to you, I'm going to build them and first check if they work, and if they perform adequately. But to save on PCB cost, some of these boards don't have mounting holes... They weren't designed to be sold. They just are designed to work, and to be integrated in larger boards.
These designs are not free. I'm keeping them to make my full system, even if there's no rocket science in them.
Last but not least, everything is surface mounted. So I'll ship most of the boards ready soldered, unless you can do it yourself. Forget about soldering these boards with a soldering iron: it sometimes is a really tight fit, and I use some 0603 parts (and even 0402 jumpers but these are just to be solder bumps to connect or not connect some lines).
Concerning the price: I still have no real idea. Expensive because I'm making few boards and only use top grade parts... I'll let you know.
That was the disclaimer/annoying stuff. Now, the fun stuff!
How is the project going on?
Boards have been sent to be made to the factory! I chose a very long delivery time to save... But well. Here it is, we're near testing!
Huh. The most important point, of course.
I have no photos of course, but here are the 3d views and descriptions!!!
On this board, there is only the DAC, and decoupling using solid polymer capacitors, big Fair Rite beads, NP0/C0G local bypass, and headers. And the clock of course. The clock is the CCHD 950 from crystek, the most expensive part.
It can be used in 2ch or 8ch mode! Your choice.
Left header: Half of the outputs.
Right header: The other 4 outputs.
Top header: Lines for all the signal imputs (so yes, you can do 8ch DSD with this board).
Bottom header: Power supplies, 7 independent lines for everything (AVCCL, AVCCR, AVDDL, AVDDR, Clock, Digital VCC, Digital VDD) with both remote sensing and remote ground sensing pins. Usefull if you want to try some super regs with remote sensing.
Bottom left header: i2c. To control the DAC.
Bottom left header, bis: Pullups. You need to have some on the i2c line at some point, so if you want to have them here, just put usual jumper on the header.
Bottom right: Control. Pins to set the i2c address, to reset, to get the "locked" and "muted" infos.
Well, everybody knows the Twisted Pear's IVY. It's basically the same thing, some slightly different stuff. I have no idea what the difference in practice will be with the IVY. I'll check. Probably should be the same thing.
- I only use big Silver Mica caps and instrumentation precision resistors in the signal path. For who cares. The footprints for the caps are compatible with ( I don't remember the ref) matching NP0 caps to minimize costs, and resistors footprints are standard 1206.
-Filtering is slightly different in that you can have a PI filter on the input, another on the output, and a resistor on input for half voltage/half current mode (see IVY about that).
-Always the same C0G/Oscon/FairRite decoupling stuff on each supply rail.
-You can shunt every part of the schematic you don't use and there are a lot of test points.
-You can plug in my gain switcher (see below)
Positive Voltage Regulator
It's made to use LT1763 or LT1963. The 1763 is 20µV noise, the 1963 is higher current/RF regulation but 40µV noise. These parts are amongst the best integrated regulators I know. And I must confess I love LT.
These can be used in adjustable mode (resistor ratio on the back) or fixed mode.
In fixed mode, you can use remote sensing or local sensing. In adj mode, local sensing only.
Negative Voltage Regulator
Guess what's in...
The LT1964, lowest noise of integrated negative regulators. Adjustable mode or fixed voltage mode. Bypass. I think that's all.
I don't know why I make this board as I probably won't use it. So I'll probably have a lot to spare.
This is a double T pad (balanced), with true bypass (disconnecting both input and output). To serve wherever you want to put it.
Feedback resistor switcher for I/V
This is a strange part. There's a relay. You can plug it in my I/V board to change the resistor in the signal path. It could switch between two output levels, or switch between 2ch or 8ch operation. The bad is that it makes a longer feedback path, and that never is good news. Test purpose, mostly.
Balanced receiver to single ended
Near everything is in the title. It's based on the best integrated circuit right now: the THAT 1200. Hey, they are cheap on mouser! So why use something not as good?
You can use it after the I/V board to drive unbalanced loads. But as it is made to be driven from not perfectly balanced load etc... it would make a great input stage for where you need it.
All these boards have been sent to factory. They are ALL made from 4 layers pcb! with solid ground plane (of course).
They all have a separate Via/hole to connect a single ground wire for star grounding of boards between them. Care has been taken that there is single non shared path to ground for everything inside each board.
Now, I'm waiting for the boards to come... Solder them... And start to cry for the mistakes I'll have made, of course!
|16th January 2009, 06:42 PM||#4|
Join Date: Oct 2003
So are you offering PCBs in a Group Buy thread or only by PM ?
Can we just buy selected PCBs or whole set ?
Empty boards of stuffed ?
I might be interested in multipel DAC boards if you can provide more detail (schematics, board outline, price, etc.).
|17th January 2009, 12:06 AM||#5|
Join Date: Dec 2007
Thank you all.
More informations to come tomorrow. First: I'm going to sleep, it's 1 AM here.
I don't sell full sets. I will sell individual boards.
There's no group buy. There only are spares that I won't use.
And I first have to test them!!!!
I will tell here how many I do have left, considering I have some people that already are on the waiting list - they are helping me since I started this project and I thank them again.
For board outlines, dimensions are on the pictures.
For schematics, I will post them of course.
Ah, and please apologize for schematics faults that I may not have updated and silkscreen flaws. Of course I'll tell you what is wrong lol.
Stuffed or empty boards, your choice.
|17th January 2009, 04:18 AM||#6|
Join Date: Jan 2008
[QUOTE : Stuffed or empty boards, your choice.]
Are you going to post for the pricing of your stuff boards and the empty boards after succesfully testing the modules?
|12th February 2009, 05:46 PM||#9|
Join Date: Dec 2007
Ok so far.
I had sent the files to the factory when I submit this thread. There were some minor flaws in the generated files so I decided to let the factory do the panelizing in the end and handle this stuff. It added further delays.
Boards should be right there in say 2 weeks maximum, given the time the post will take (they will come from eastern europe).
Sorry for the long wait and not having kept you up to date.
|22nd February 2009, 04:27 PM||#10|
Join Date: Dec 2007
I'm so late. I feel lame. Should have accounted for the time for the international bank transfer too, and time for the panelizing design, and gerber files correction etc. Plus I ordered solder screens too.
Just have to wait.
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