Yeah it is the "spring festival" in china so hardly any of the chinese vendors have shipped anything in a week or more, and won't be shipping until february.
I'm trying to resist ordering up board and transformer. I hardly need another project. I should finish up at least a couple others first.
I'm trying to resist ordering up board and transformer. I hardly need another project. I should finish up at least a couple others first.
Something I just noticed, is that the ceramic bypass caps for the various supplies on the ak4495 are not consistent. The VREF neg don't have the bypass caps. I am assuming that this was because of space constraints on the board.
While I was considering removing all of these to avoid interactions with the electrolytic caps, better sound, I thought it was odd since most of these boards follow the datasheet examples.
While I was considering removing all of these to avoid interactions with the electrolytic caps, better sound, I thought it was odd since most of these boards follow the datasheet examples.
What do you do with circuit boards when you can't listen to them?
I tend to look them over, now noticing the output filter that bears a striking resemblance to the one on the AKM evaluation board, but several of the capacitor values have been changed, as I had suspected...
I'm sure it will sound good, however, I had planned on replacing these, so will put it back to the datasheet example as soon as I can make sure it powers up. I figure after this many versions of a product, that they should have a fairly good idea of how to get the most out of it.
I tend to look them over, now noticing the output filter that bears a striking resemblance to the one on the AKM evaluation board, but several of the capacitor values have been changed, as I had suspected...
I'm sure it will sound good, however, I had planned on replacing these, so will put it back to the datasheet example as soon as I can make sure it powers up. I figure after this many versions of a product, that they should have a fairly good idea of how to get the most out of it.
...and the resistors too, in a most dyslexic manner; I would suggest checking your board if you have one.
The values of the filter capacitors must have been the result of availability, the corner points are so far from typical suggested values. For the example a 5khz -3db point vs 13 or 14khz as per the data sheet example. That's on the + input, the other was at 50khz or so.
It gets a bit better having the resistors placed correctly, also the gain is super low with the provided 2.7k in the feedback loop. Is an easy fix to remove one of the two resistors that are paralleled in that position, then nearly identical to the data sheet example.
Almost not worth powering up as it is, but I don't want to do anything to it without making sure it works first.
The values of the filter capacitors must have been the result of availability, the corner points are so far from typical suggested values. For the example a 5khz -3db point vs 13 or 14khz as per the data sheet example. That's on the + input, the other was at 50khz or so.
It gets a bit better having the resistors placed correctly, also the gain is super low with the provided 2.7k in the feedback loop. Is an easy fix to remove one of the two resistors that are paralleled in that position, then nearly identical to the data sheet example.
Almost not worth powering up as it is, but I don't want to do anything to it without making sure it works first.
Interesting: I will check mine tonight. Is the DC offset going down after startup?
I wonder if you also get a loud 'plop' on both channels when the first track is played.
That plop never happens again until next power up after some extensive cooling down.
I get no plop after a quick restart.
I get a click on shutdown and a pop on startup, if I don't turn the amplifier on after, which is my routine.
Still have the offset going on, will replace the capacitors in the output filter first, then move on to the resistors. Seems backwards, but I know I will only need to change the caps once.
The epay vendor gave me an eval version of the driver for windows, could have found that on my own, beeps and all.
Any sources for a legit, fully functioning driver by chance?
Still have the offset going on, will replace the capacitors in the output filter first, then move on to the resistors. Seems backwards, but I know I will only need to change the caps once.
The epay vendor gave me an eval version of the driver for windows, could have found that on my own, beeps and all.
Any sources for a legit, fully functioning driver by chance?
I am using this driver which seems to be the most recent (2016-02-16):
XMOS-USB-Audio-(v3.34.0).rar, found here
Probably legit
, no beep.
Yes, please post what you have done. I have ordered a similar DAC but with I2S entry. The layout of DAC and Output filter looks similar. It would be interesting what exactly you did, which parts were removed and which values you put as resistors and capacitors - maybe you could Show this on a photo of your board?
Thanks a lot!
Thanks a lot!
Hi here!
Does this board DSD ? (I don't think so)...
But if i am right, why is it so? -As far as i can see, bot the akm4495seq and the xmos support DSD (Native?)
I asked one seller, if his card was playing DSD, and the answer was no?
Maybee he was wrong?, but anyway if it could wouldent it be written in the salespages on ebay?
Voice & Audio Interfaces | XMOS
Assembled XMOS U8 + AK4495SEQ + AD827 DAC USB Decoder Board | eBay
AK4495SEQ | Product | AKM - Asahi Kasei Microdevices
Does this board DSD ? (I don't think so)...
But if i am right, why is it so? -As far as i can see, bot the akm4495seq and the xmos support DSD (Native?)
I asked one seller, if his card was playing DSD, and the answer was no?
Maybee he was wrong?, but anyway if it could wouldent it be written in the salespages on ebay?
Voice & Audio Interfaces | XMOS
Assembled XMOS U8 + AK4495SEQ + AD827 DAC USB Decoder Board | eBay
AK4495SEQ | Product | AKM - Asahi Kasei Microdevices
I haven't explored the possibility of DSD, not enirely sure of the merits of that enough to have pursued it. So much of the sound impression comes from the analog portion I have noticed.
Maybe the next generation of diy boards will welcome those improvements, since commercial products are out with that feature.
I found some Epcos main filter caps to use, after it runs a bit here first. I noticed that one of the regulators, the one for the xmos portion, was very warm for the first ten hours or so. Am glad to have it a bit cooler to the touch now. The case I used now has a mini-version of a line conditioner, that is a 1 uf X capacitor, and a few turns around a ferrite core.
After listening to another setup I had modified over the course of a couple years, I am again beginning to appreciate the work the goes into getting the sound the way I want it.
I will try to get a picture of my diagram I made, I know the values printed on the board are what the akm evaluation board suggests.
Maybe the next generation of diy boards will welcome those improvements, since commercial products are out with that feature.
I found some Epcos main filter caps to use, after it runs a bit here first. I noticed that one of the regulators, the one for the xmos portion, was very warm for the first ten hours or so. Am glad to have it a bit cooler to the touch now. The case I used now has a mini-version of a line conditioner, that is a 1 uf X capacitor, and a few turns around a ferrite core.
After listening to another setup I had modified over the course of a couple years, I am again beginning to appreciate the work the goes into getting the sound the way I want it.
I will try to get a picture of my diagram I made, I know the values printed on the board are what the akm evaluation board suggests.
So this thread below has what every owner of one of these boards should be aware of, that is the intended schematic/board layout. It shows how one of the resistor values has been changed from the AK evaluation board example, and this is what I believe to contribute to the large DC offset.
http://www.diyaudio.com/forums/digi...ed-ak4495-ak4118-dac-today-9.html#post4471473
Note that r8 is 3.6k in the manufacturers suggestion, while my board at least, has this position using a 3.3k.
Also on my board, r5, r3 were both 5.4k.
http://www.diyaudio.com/forums/digi...ed-ak4495-ak4118-dac-today-9.html#post4471473
Note that r8 is 3.6k in the manufacturers suggestion, while my board at least, has this position using a 3.3k.
Also on my board, r5, r3 were both 5.4k.
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I saw that there were errors in that diagram from the other board I had referenced, two of the resistors has been given the same designation, as well as the ones you noticed. Sorry about that, it gives a good idea of the board layout though aside from the errors. I had already made a similar diagram to follow for my work.
I plan on just adding a resistor over the 3.3k to bring it to 3.6k(underside of the board), that should greatly reduce the offset.
For me that will be a trip to the store, and won't happen until a week or so, currently l have replaced all of the tiny filter capacitors with the values suggested in the AKM schematic for the evaluation board, as well as the power supply (after regulator, bypasses) for the op amp.
I used some Wima FKP2 that were available for the filter and local bypass on the op amp. The electrolytic parts I used were some Elna Silmic ARS that were surplus parts from the "bay".
The 8 capacitors around the AK chip have smd bypassed on all but two, the neg VREF.
I plan on using some 47uf 25v Panasonic pureism parts to replace all but the DVDD, which will be a 47uf solid polymer-type. I will likely remove the smd parts to avoid interactions(ringing) on the supplies around the AK chip.
For now I will listen and enjoy. The sound is a lot more bold now, and will smooth out more in days to come. There is no shortage of detail with these boards, are very nice.
I plan on just adding a resistor over the 3.3k to bring it to 3.6k(underside of the board), that should greatly reduce the offset.
For me that will be a trip to the store, and won't happen until a week or so, currently l have replaced all of the tiny filter capacitors with the values suggested in the AKM schematic for the evaluation board, as well as the power supply (after regulator, bypasses) for the op amp.
I used some Wima FKP2 that were available for the filter and local bypass on the op amp. The electrolytic parts I used were some Elna Silmic ARS that were surplus parts from the "bay".
The 8 capacitors around the AK chip have smd bypassed on all but two, the neg VREF.
I plan on using some 47uf 25v Panasonic pureism parts to replace all but the DVDD, which will be a 47uf solid polymer-type. I will likely remove the smd parts to avoid interactions(ringing) on the supplies around the AK chip.
For now I will listen and enjoy. The sound is a lot more bold now, and will smooth out more in days to come. There is no shortage of detail with these boards, are very nice.
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I fixed some errors in post#99 of the thread :
http://www.diyaudio.com/forums/digi...iang-released-ak4495-ak4118-dac-today-10.html
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