Philippe
, is there no increase of ground loop size to use 2 caps like in your picture = the importance of the little size get off with populating with the bigger one ?
, is there no increase of ground loop size to use 2 caps like in your picture = the importance of the little size get off with populating with the bigger one ?
I would consider a 1uF a reservoir cap more than a decoupling cap (this is more terminology, as both are 'decoupling', but small case size low values 0.47uF and lower next to the pins are more often termed decoupling capacitor and the larger sizes and 0.47uf and above are termed reservoir capacitors.
The small value small size COGs help reduce the harmonic noise that an oscillator creates, as they have very square wave outputs, (fast rise times so more higher frequency harmonics), a OCG was found to be better than just X7Rs on there own as they have better RF performance, the testing and circuitry was for far more sensitive equipment than a DAC, and may not be as critical in this instance, but I would still recommend fitting one if you can, it can only help. The version of the layout I am playing with will have positions for these extra decoupling caps as I do consider them important.
As to aging, X7R X8Rs etc they are used on mil/aero/medical/auto equipment, where long life and reliability are paramount.
The small value small size COGs help reduce the harmonic noise that an oscillator creates, as they have very square wave outputs, (fast rise times so more higher frequency harmonics), a OCG was found to be better than just X7Rs on there own as they have better RF performance, the testing and circuitry was for far more sensitive equipment than a DAC, and may not be as critical in this instance, but I would still recommend fitting one if you can, it can only help. The version of the layout I am playing with will have positions for these extra decoupling caps as I do consider them important.
As to aging, X7R X8Rs etc they are used on mil/aero/medical/auto equipment, where long life and reliability are paramount.
Thank you very much Marce for you complete answer and valuable informations.
I'll try to fit & solder both caps - 1nF COG & 1uF MLCC X7R in this little pad area.
Eldam, I've got few spare time left for mods...
So, I suggest you to keep on testing and report your results 😉
Regards
Phil
I'll try to fit & solder both caps - 1nF COG & 1uF MLCC X7R in this little pad area.
Eldam, I've got few spare time left for mods...
So, I suggest you to keep on testing and report your results 😉
Regards
Phil
Lol Phil, you make the same with your picture and question ??? 😉 you are still in a mods thread 🙄 No, 2 caps at C17 is not a mods at all...lol.
I don't talk about mods here...
it was just a theoric question about your picture with two caps near the crystal.
As one cap is bigger than the others then in the same place (even if the littlier is near the crystal) and as i surmise your are looking for the best result by asking yourself before.
As you have not a specific pcb but the genuine one, don't you think two little caps with one bigger do increase parasitic inductance and local ground loop or not and minimize the profit of the littlier one in size ?
mes meilleurs... et un peu de respect mon gars malgré le clin d'oeil s'il vous plait... I just said I didn't ask anything to JP whom helped a lot before.
I don't talk about mods here...
it was just a theoric question about your picture with two caps near the crystal.
As one cap is bigger than the others then in the same place (even if the littlier is near the crystal) and as i surmise your are looking for the best result by asking yourself before.
As you have not a specific pcb but the genuine one, don't you think two little caps with one bigger do increase parasitic inductance and local ground loop or not and minimize the profit of the littlier one in size ?
mes meilleurs... et un peu de respect mon gars malgré le clin d'oeil s'il vous plait... I just said I didn't ask anything to JP whom helped a lot before.
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Dear Eldam,
As mentionned COG cap will be in 0603 package and X7R a 0805 one.
They are intended to replace C17 whose size is 1210.
I think there is enough space there to fit those two caps.
Maybe I'm wrong but I'll try.
Concerning parastic inductance and Gnd loop, Marce has given us some nice hints.
He would have mention it in case of special care, but he don't.
So, I'll go this way 😉
Regards
Phil
As mentionned COG cap will be in 0603 package and X7R a 0805 one.
They are intended to replace C17 whose size is 1210.
I think there is enough space there to fit those two caps.
Maybe I'm wrong but I'll try.
Concerning parastic inductance and Gnd loop, Marce has given us some nice hints.
He would have mention it in case of special care, but he don't.
So, I'll go this way 😉
Regards
Phil
Thank you marce for your didactic answer.
About the agging, it's very interresting : It's not easy for a non technician like me to organize into a hieararchy the importance of informations in the white papers (i read your link and after white papers from anothers brands or electronics suppliers like Analog devices) both as you said there are different uses between devices and some of these white papers are written by the manufacters which are vendor as well.
About the agging, it's very interresting : It's not easy for a non technician like me to organize into a hieararchy the importance of informations in the white papers (i read your link and after white papers from anothers brands or electronics suppliers like Analog devices) both as you said there are different uses between devices and some of these white papers are written by the manufacters which are vendor as well.
korben,
I am interrested by your input after your test in relation to the standalone 1 uf 1210 smd. I didn't understand if C17 is needed just for decoupling high frequencies noise or is usefull both for a faster reservoir cap as there is already a filtered current before with ferrite bead. My understanding was Marce maid a specific pcb for it.
Tell us please if you have time if a difference can be heard in your system.
I am interrested by your input after your test in relation to the standalone 1 uf 1210 smd. I didn't understand if C17 is needed just for decoupling high frequencies noise or is usefull both for a faster reservoir cap as there is already a filtered current before with ferrite bead. My understanding was Marce maid a specific pcb for it.
Tell us please if you have time if a difference can be heard in your system.
The BIG advantage this design has over most of the others I have seen is each section has its own regulated supply, with a pi-filters and inductors, and the distance from these supplies to their respective devices is small, so we have an optimal supply situation to start with, the rest is icing on the cake.
I am playing around with this design, the full PSU and the JG buffer, and currently have a range of layouts. initially I am concentrating on SMD based designs with the smallest component being 0603 chip devices as I think these are the limit for basic DIY. I will also eventually do a full version with all the mod options on, though my own belief and experience with digital layout is that PTH caps with the added lead inductance are not going to improve things, they wont make things worse either, but are much easier for DIYers to play with.
below is some early screen shots from two of the earlier versions, all the DAC part is single sided placement and routing with the only vias being GND vias, this gives a contagious ground plane on the bottom layer on the digital side, this is a requirement for digital signal fidelity (signal integrity/EMC).
I am playing around with this design, the full PSU and the JG buffer, and currently have a range of layouts. initially I am concentrating on SMD based designs with the smallest component being 0603 chip devices as I think these are the limit for basic DIY. I will also eventually do a full version with all the mod options on, though my own belief and experience with digital layout is that PTH caps with the added lead inductance are not going to improve things, they wont make things worse either, but are much easier for DIYers to play with.
below is some early screen shots from two of the earlier versions, all the DAC part is single sided placement and routing with the only vias being GND vias, this gives a contagious ground plane on the bottom layer on the digital side, this is a requirement for digital signal fidelity (signal integrity/EMC).
Héhé... it is the unofficial V4 😀
Do the plated through hole caps exist for polymers with the same capacitance value and ESR but with less inductance than the bulk one ? there also between "smd bulk" with the tiny pretty little pads on each side of its plastic base !
It's interresting to know the limit of what the ears are abble to hear between two close layout. But there are maybe too much parameters removed like the complex cap mathematic equivalent when another caps are used...
When I say this DAC is fantastic for fool enthusiast like me to understand more...🙂
Do the plated through hole caps exist for polymers with the same capacitance value and ESR but with less inductance than the bulk one ? there also between "smd bulk" with the tiny pretty little pads on each side of its plastic base !
It's interresting to know the limit of what the ears are abble to hear between two close layout. But there are maybe too much parameters removed like the complex cap mathematic equivalent when another caps are used...
When I say this DAC is fantastic for fool enthusiast like me to understand more...🙂
Doing the layout is a bit of fun for me, a change doing a PCB for my own enjoyment without project managers breathing down your throat. But also I will end up with a few variants on a theme. The simplest design I put up earlier would make a nice easy DIY project for a first timer or new to this, the PCBs can be etched at home or a batch will be affordable, it is a good design to practice SMD soldering skills without breaking the bank, and at the end of it you get a working DAC (I am going to add a power connector and USB connector so you have a choice of powering options, from a wall wart.
For the more advanced and tweakers I am going to add all the options on the original circuit, plus the PSU and the JG buffer, possibly with on board regulators:
When I am ready we must start a new thread, then any request will be considered...🙂
The story so far...though I am not happy with it at the moment, I want to move the local supplies round to reduce the track length to the power pins.
For the more advanced and tweakers I am going to add all the options on the original circuit, plus the PSU and the JG buffer, possibly with on board regulators:
When I am ready we must start a new thread, then any request will be considered...🙂
The story so far...though I am not happy with it at the moment, I want to move the local supplies round to reduce the track length to the power pins.
Bravo.
The sucess of this little DAC chip is impressive. Step by step the Wolfsons, AD or BB loose altitude in the sky of affordable DIY projects.
The sucess of this little DAC chip is impressive. Step by step the Wolfsons, AD or BB loose altitude in the sky of affordable DIY projects.
has anyone implemented the i2s connection with Amanero 😕
seems that the only mods that are being discussed here are caps 😀
Hi
I've done it using Subbu DAC V3 Beta PCB but without UF-L connectors and an USB Isolator who requires a PSU.
In your case, you need to pick I2S from R4/5/6 lines on Subbu DAC.
You need at least one digital Gnd on ES9023 as return path for I2S signal. (ie pin 14 DGND). Try to make your connexion short.
From Amanero to Subbu DAC V3 :
LRCK Line goes to R6 (LRCK)
BCK Line goes to R5 (BCK)
DATA Line goes to R4 (SDI)
Regards
Phil
Pchw, I have a bib psu board on the way to try with the Subbu. Do I need to know the impedance as well? What value for the dummy load resistor should I use for making the adjustments to the psu to achieve 280ma. I will be ordering a 12.6v .5amp transformer. Sorry to keep asking my novice questions here. Thanks. Regards.
The V3 DAC draws about 80ma, so a 60 ohm resistor is a pretty good approximation of the DAC when setting up the shunt regulator. The resistor should be rated at 1W for safety.
---Gary
Hi Freeman,
If the reg is at the ball part from the get go, then a 50 - 60 ohm 1W resistor will be good to use. Use Ohm's Law:
5V / 50 ohm (just for easy calculation) is 100ma, so the dissipation of the dummy load will be 5V * 100ma = 0.5W. 1 watt is good enough.
I use a 50ohm 10W resistor because I happened to have one, but more important, I wasn't sure what voltage coulld appear at the output. I use a 9-0-9 2A transformer, so potentially, I could send all 12VDC into the load, that will be around 3W. I simply played safe on the err side 🙂
Your transformer is somewhat marginal for 280ma once you consider at least 10% loss in (transformer) regulation. It will run hot. I suggest to start with 150ma first and see how hot the transformer is. If you feel it has more juice, you can always solder another resistor parallel to the CCS set resistor (R101) to increase the current. It is easier to increase the current this way.
If the reg is at the ball part from the get go, then a 50 - 60 ohm 1W resistor will be good to use. Use Ohm's Law:
5V / 50 ohm (just for easy calculation) is 100ma, so the dissipation of the dummy load will be 5V * 100ma = 0.5W. 1 watt is good enough.
I use a 50ohm 10W resistor because I happened to have one, but more important, I wasn't sure what voltage coulld appear at the output. I use a 9-0-9 2A transformer, so potentially, I could send all 12VDC into the load, that will be around 3W. I simply played safe on the err side 🙂
Your transformer is somewhat marginal for 280ma once you consider at least 10% loss in (transformer) regulation. It will run hot. I suggest to start with 150ma first and see how hot the transformer is. If you feel it has more juice, you can always solder another resistor parallel to the CCS set resistor (R101) to increase the current. It is easier to increase the current this way.
Thanks pchw. I have a hammond 12-0-12 25va in my parts bin which seems to be a better fit. How are the three secondary wires connected to the Salas board? Regards.
It can be done to set up the BiB board for full wave rectification, but it doesn't look at neat as the full wave bridge. I ended up doing wiring up point-2-point which allowed me to use my existing parts.
I will dig out my notes after work to show you how to do it.
I will dig out my notes after work to show you how to do it.