Hi everybody!
As some may know, I'm working on a DAC made from the ESS Sabre.
I promised to a tenth of people that they could get their hands on these boards. I will email them again when project will be finished. Price will be quite high, I'll explain you why, but I'll make no profit.
My goal is to make independent boards with a lot of connectors, to try the DAC with several I/V, several regulators, the digital input you want, the use of i2c to command the chip... Well, everything outboard.
Onboard:
- 4 Layers board
- All big caps Oscons
- All small caps np0/c0g to avoid microphonic effect when used for live events
- Big FairRite beads with very low Rdc (6.2mOhms)
-Power supply header with sensing and ground sensing pins.
-All input pins on the input header (if you want DSD...)
-Control header of everything that can be set up physically (to use with remote µC)
This project is taking me much more time than it should, but I had no luck: first version (about only the schematic) burnt with my computer. After having redone it and drawn footprints for shielded sub-d connectors, I accidentally erased my work. Yes I know I got no luck...
I forgot the sub-d connectors (takes forever to draw...), remade the schematic, and started to remake the PCB
Then, the first questions comes... Next post to keeps things clean.
As some may know, I'm working on a DAC made from the ESS Sabre.
I promised to a tenth of people that they could get their hands on these boards. I will email them again when project will be finished. Price will be quite high, I'll explain you why, but I'll make no profit.
My goal is to make independent boards with a lot of connectors, to try the DAC with several I/V, several regulators, the digital input you want, the use of i2c to command the chip... Well, everything outboard.
Onboard:
- 4 Layers board
- All big caps Oscons
- All small caps np0/c0g to avoid microphonic effect when used for live events
- Big FairRite beads with very low Rdc (6.2mOhms)
-Power supply header with sensing and ground sensing pins.
-All input pins on the input header (if you want DSD...)
-Control header of everything that can be set up physically (to use with remote µC)
This project is taking me much more time than it should, but I had no luck: first version (about only the schematic) burnt with my computer. After having redone it and drawn footprints for shielded sub-d connectors, I accidentally erased my work. Yes I know I got no luck...
I forgot the sub-d connectors (takes forever to draw...), remade the schematic, and started to remake the PCB
Then, the first questions comes... Next post to keeps things clean.
Ok, so I'm making the routing.
4 layers board is here to get the best out of it. It may reveal useless, but if you don't try... you don't know. There have not been any 4-layers board made for this chip yet.
The first question is about placement of my Oscons caps.
What you see is the right of the Sabre.
Oh note: it's a mess, it's not the real routing, I'm just drawing lines to figure out the best placement for each component. I'll clean it up, don't worry xD
Well, you see 4 analog lines (red) on top, and 4 analog lines under.
In the middle, blue pads, circled in yellow, are Oscons decoupling caps. I put them here.
Under everything, blue pads, in a yellow square, are FairRite beads.
Of course, both are connected.
Light blue are power connections (imagine it as polygon fills).
The question is:
Is it best to keep Caps where they are, and run the line to the bead perpendicular to analog lines (shown example)?
Or should I put the caps near the beads, further under the analog lines (where the beads are now) and run the "cleant" power line under the analog lines?
The pros of the first are:
- Connection to DAC's power pins are kept short
- Equal distance of the analog lines from the caps mean that all channels should sound the same (same perturbation from caps)
Cons:
- Caps are near the analog lines and may mess them up
Pros of the second solution:
- Caps are further away from analog lines
- But they only are on one side
- Connection to DAC's power pins are longer (but connections will be polygons anyway so it may not be THAT bad).
What do you think I should do?
Thank you
Pic:
4 layers board is here to get the best out of it. It may reveal useless, but if you don't try... you don't know. There have not been any 4-layers board made for this chip yet.
The first question is about placement of my Oscons caps.
What you see is the right of the Sabre.
Oh note: it's a mess, it's not the real routing, I'm just drawing lines to figure out the best placement for each component. I'll clean it up, don't worry xD
Well, you see 4 analog lines (red) on top, and 4 analog lines under.
In the middle, blue pads, circled in yellow, are Oscons decoupling caps. I put them here.
Under everything, blue pads, in a yellow square, are FairRite beads.
Of course, both are connected.
Light blue are power connections (imagine it as polygon fills).
The question is:
Is it best to keep Caps where they are, and run the line to the bead perpendicular to analog lines (shown example)?
Or should I put the caps near the beads, further under the analog lines (where the beads are now) and run the "cleant" power line under the analog lines?
The pros of the first are:
- Connection to DAC's power pins are kept short
- Equal distance of the analog lines from the caps mean that all channels should sound the same (same perturbation from caps)
Cons:
- Caps are near the analog lines and may mess them up
Pros of the second solution:
- Caps are further away from analog lines
- But they only are on one side
- Connection to DAC's power pins are longer (but connections will be polygons anyway so it may not be THAT bad).
What do you think I should do?
Thank you
Pic:
An externally hosted image should be here but it was not working when we last tested it.
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