I don´t have it yet, but some here in this Forum already used this board with I2S Connection from a Kali. I ordered it on Thanksbuyer:
AK4495S SEQ II2S DAO Decode Board AD827 Operational Amp LT1963-3.3 - Free Shipping - ThanksBuyer
As my Aroio Image (including squeezelite and a convolver for room correction) does not support a simple I2S out (and I do not know how to apply e.g. Hifiberry DAC driver into the Image to run it with Kali as well) I will use the supported Hifiberry DAC+ pro and its I2S out to run the AK4495 board. This works already with a cheap ES9023 DAC as slave (Master clock delivered by HBD+pro) and sounds very well!
AK4495S SEQ II2S DAO Decode Board AD827 Operational Amp LT1963-3.3 - Free Shipping - ThanksBuyer
As my Aroio Image (including squeezelite and a convolver for room correction) does not support a simple I2S out (and I do not know how to apply e.g. Hifiberry DAC driver into the Image to run it with Kali as well) I will use the supported Hifiberry DAC+ pro and its I2S out to run the AK4495 board. This works already with a cheap ES9023 DAC as slave (Master clock delivered by HBD+pro) and sounds very well!
I was hoping to get away without a fan this time around, however, it's not looking that way.
The regulators run at about 115F, which isn't too bad, but if I put anything resembling a cover on the case, the temps start to climb pretty fast.
Another contributor to the heat, the Audiofeel 301 op amp is running at 118, so I think I will have to take it apart and place a 50mm fan into the panel that separates the transformer from the dac. I really didn't expect that, and it does sound very good, especially for $30!
The regulators run at about 115F, which isn't too bad, but if I put anything resembling a cover on the case, the temps start to climb pretty fast.
Another contributor to the heat, the Audiofeel 301 op amp is running at 118, so I think I will have to take it apart and place a 50mm fan into the panel that separates the transformer from the dac. I really didn't expect that, and it does sound very good, especially for $30!
Hi,
some update to my AK4495SEQ DAC experience.
My board arrived now. I did following mods on it:
- check all output filter resistors - only one was wrong compared to AKM dev. board description. Nearly all capacitors in filter stage were changed to WIMA FKP 2 types with correct values.
- Removed filter switch (did anybody check if the setup makes sense putting Jumper in 90 deg direction to switch connections here? I could not hear any difference...)
- Zener diods were changed to a selected pair as I noted a voltage drop difference between the mounted ones (15,3V vs. 15,1 V) but this did not change my output offset of 9 mV I had after filter adjustment described above.
- Aluminum capacitors around DAC chip were changed to 220uF/10V Panasonic FM types. Only the one with 100uF on board layout was changed to a organic polymer FP type with 6,3V and 380 uF (ESR 7mOhm!)
- Output channel identification is wrong, left is right and right is left
- 4x big capacitors and 2x small ones for PSU were changed to Panasonic FM types (480uF and 330uF / 35V)
- 3x 4700uF entry PSU Nover caps remained (maybe they are fake, but difficult to find same size..)
- current buffer caps for OP amp were replaced to 16V FP polymer types, 330uF
- after the AD827 op-amp burned for some reason (left channel suddenly no sound any more...) I replaced it by a LME49720.
- -9,5 dB attenuation by 390 Ohm serial and 200 Ohm parallel resistors / channel (220 and 110 seemed to much load for the op-amp to me) at the output.
Sound: Feeding the I2S from my raspberry Pi with Hifiberry DAC+ pro I realized a even more precise and defined high range, more micro dynamics and better separation between instruments with a more precise staging compared to my orig. set-up with Kali+Piano 2.1.
I realized a big Impact of the OP-amps to the sound performance. The AD827 was very good, too, especially with a dry kicking bass and smooth midrange. The LME sounds a little more analytic, but some how more precise, but still smooth. The NE5532 is also not too bad with a very strong bass Performance but some harshness in high frequency compared to the others.
I am very happy with this result which will become my new main-System now. The ring-transformer from Thanksbuyers was a mess, as the tensions were all but correct and wrong wired - I ordered an R-core on ebay (2x 0-15V, 2x 0-9V) which works perfectly and has a very small size. Further I can run the RPi with the 4th pair of 0-9V which saves space in my new housing.
This was a really fun Project which can highly be recommanded. Thanks for your inputs and investigations on the mods. ;-)
some update to my AK4495SEQ DAC experience.
My board arrived now. I did following mods on it:
- check all output filter resistors - only one was wrong compared to AKM dev. board description. Nearly all capacitors in filter stage were changed to WIMA FKP 2 types with correct values.
- Removed filter switch (did anybody check if the setup makes sense putting Jumper in 90 deg direction to switch connections here? I could not hear any difference...)
- Zener diods were changed to a selected pair as I noted a voltage drop difference between the mounted ones (15,3V vs. 15,1 V) but this did not change my output offset of 9 mV I had after filter adjustment described above.
- Aluminum capacitors around DAC chip were changed to 220uF/10V Panasonic FM types. Only the one with 100uF on board layout was changed to a organic polymer FP type with 6,3V and 380 uF (ESR 7mOhm!)
- Output channel identification is wrong, left is right and right is left
- 4x big capacitors and 2x small ones for PSU were changed to Panasonic FM types (480uF and 330uF / 35V)
- 3x 4700uF entry PSU Nover caps remained (maybe they are fake, but difficult to find same size..)
- current buffer caps for OP amp were replaced to 16V FP polymer types, 330uF
- after the AD827 op-amp burned for some reason (left channel suddenly no sound any more...) I replaced it by a LME49720.
- -9,5 dB attenuation by 390 Ohm serial and 200 Ohm parallel resistors / channel (220 and 110 seemed to much load for the op-amp to me) at the output.
Sound: Feeding the I2S from my raspberry Pi with Hifiberry DAC+ pro I realized a even more precise and defined high range, more micro dynamics and better separation between instruments with a more precise staging compared to my orig. set-up with Kali+Piano 2.1.
I realized a big Impact of the OP-amps to the sound performance. The AD827 was very good, too, especially with a dry kicking bass and smooth midrange. The LME sounds a little more analytic, but some how more precise, but still smooth. The NE5532 is also not too bad with a very strong bass Performance but some harshness in high frequency compared to the others.
I am very happy with this result which will become my new main-System now. The ring-transformer from Thanksbuyers was a mess, as the tensions were all but correct and wrong wired - I ordered an R-core on ebay (2x 0-15V, 2x 0-9V) which works perfectly and has a very small size. Further I can run the RPi with the 4th pair of 0-9V which saves space in my new housing.
This was a really fun Project which can highly be recommanded. Thanks for your inputs and investigations on the mods. ;-)
What transformers do you use for powering the DAC board? 2 sparate ones?
Did you board have 680 uF Elna caps?
Which resistor was wrong?
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The hot regulator on the other board is the one servicing the XMOS chip which is absent on yours.
Post#73 of this thread talk about filters in hardware mode and about the associated inputs : SD - SLOW - SSLOW
removing the dip switch is not enough, you should mod SSLOW pin in order to expect some sound differences, otherwise you're stuck with SSLOW filter
Chris
Hi all,
"What transformers do you use for powering the DAC board? 2 sparate ones?"
- It is a single one with 4 outlines from ebay (30W, from Hongkong 2x 15V/0,5A and 2x9V/0,8A)
Did you board have 680 uF Elna caps?
- Yes, it was written on it, but I had my doubts so I changed them to 480uF Panasonic
Which resistor was wrong?
- the 3,2 kOhm I changed it to 3,6 kOhm
The hot regulator on the other board is the one servicing the XMOS chip which is absent on yours.
- OK, lucky me to not have it.. ;-)
you should mod SSLOW pin in order to expect some sound differences, otherwise you're stuck with SSLOW filter
- I will check again, if Pin 12 is grounded or not..
"What transformers do you use for powering the DAC board? 2 sparate ones?"
- It is a single one with 4 outlines from ebay (30W, from Hongkong 2x 15V/0,5A and 2x9V/0,8A)
Did you board have 680 uF Elna caps?
- Yes, it was written on it, but I had my doubts so I changed them to 480uF Panasonic
Which resistor was wrong?
- the 3,2 kOhm I changed it to 3,6 kOhm
The hot regulator on the other board is the one servicing the XMOS chip which is absent on yours.
- OK, lucky me to not have it.. ;-)
you should mod SSLOW pin in order to expect some sound differences, otherwise you're stuck with SSLOW filter
- I will check again, if Pin 12 is grounded or not..
Assuming that Chinese AK4495 boards with the 2 red dipswitch have the same pcb layout and design, at least for the 4495 section, we can say that AK4495 operate in hardware mode as did mine and others seen on DIYA. In this mode the behavior of the chip is setup by some pins and not by the registers using a microcontroller.
In hardware mode AK4495 digital filter selection is made by 3 pins according the following table:
SD pin....SLOW......SSLOW pin............Filter
0..............0..............0......................Sharp Roll Off
0..............1..............0......................Slow Roll Off
1..............0..............0......................Short Delay Sharp Roll Off
1..............1..............0......................Short Delay Slow Roll Off
x..............x..............1......................Super Slow Filter
Dip switches are connected to pin SD and SLOW.
Thus, the two jumpers you plan to install in order to replace the dip switchs may only have an effect on filter selection if SSLOW pin is not tied to VDD (High Level). SSLOW is pin 5.
In hardware mode AK4495 digital filter selection is made by 3 pins according the following table:
SD pin....SLOW......SSLOW pin............Filter
0..............0..............0......................Sharp Roll Off
0..............1..............0......................Slow Roll Off
1..............0..............0......................Short Delay Sharp Roll Off
1..............1..............0......................Short Delay Slow Roll Off
x..............x..............1......................Super Slow Filter
Dip switches are connected to pin SD and SLOW.
Thus, the two jumpers you plan to install in order to replace the dip switchs may only have an effect on filter selection if SSLOW pin is not tied to VDD (High Level). SSLOW is pin 5.
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On my board pin 5 seems to be grounded (no SSLOW mode). The right line of the switch connections which connects the Jumpers is tied to pin 12 and connected with VDD (pin 44) so should be High (parallel mode).
pin 7 and 8 are connected to the free jumper pins on left side, so any jumper set will put each of them into hHgh mode, too as connected to VDD (pin 44).
The resistor to Gnd on these pins 7 and 8 avoids them floating when no jumper is set, I guess, but I wonder what is the right value for them? Would it make sense to replace them or remove them in case a jumper is set?
pin 7 and 8 are connected to the free jumper pins on left side, so any jumper set will put each of them into hHgh mode, too as connected to VDD (pin 44).
The resistor to Gnd on these pins 7 and 8 avoids them floating when no jumper is set, I guess, but I wonder what is the right value for them? Would it make sense to replace them or remove them in case a jumper is set?
Any value between 1K and 1M is ok, those are pull down resistors on a MOS input.
Do you hear differences between the 4 filters ?
I will first be able to listen in a week. My first quick check with one jumper did not show a dramatic impact..(I did not even realyze any change..) but I have to do it again with more time.
You say the resistors are not to Gnd but between Vdd and DAC pin7 / 8 when a jumper is set? I will check the values first and maybe remove one where I set the jumper if I cannot hear a difference..
You say the resistors are not to Gnd but between Vdd and DAC pin7 / 8 when a jumper is set? I will check the values first and maybe remove one where I set the jumper if I cannot hear a difference..
I've only said those are 'pull down' because you said they're tied to ground.
I didn't see any reason to change or mod them.
My DAC has been moded to operate in serial mode and I can't hear any difference between the 5 filters and the 5 SQQ settings.
Maybe those are my hears that should be moded !
, or not...Wow, thanks for the detailed breakdown of the filter scenarios, don't think the data sheet covered that nearly as well.
Many hours on mine so far, still can't shake the slightly boosted midrange. Am going to look at the regulators/power supplies next. Might be a good job for a scope, however.
I have seen a commercial implementation of the ak4495 where there are no local smd bypass capacitors on the pins, everyone loves it. Also with that one, the Short Delay, Sharp Rolloff was said to provide better bass. It was made by Giesler in Australia. They were using an Amenero USB also, fwiw.
Many hours on mine so far, still can't shake the slightly boosted midrange. Am going to look at the regulators/power supplies next. Might be a good job for a scope, however.
I have seen a commercial implementation of the ak4495 where there are no local smd bypass capacitors on the pins, everyone loves it. Also with that one, the Short Delay, Sharp Rolloff was said to provide better bass. It was made by Giesler in Australia. They were using an Amenero USB also, fwiw.
So, you still have the boosted mid issue. On my setup it disappeared, but I don't accurately know after which mod and in which domain: analog or digital.
Could you post a pic of your board?
My project is shown here; http://www.diyaudio.com/forums/digital-line-level/302211-ebay-usb-dac-board-7.html#post4992542
The midrange thing has gotten better with mine also, but improvement has been so gradual I almost can't tell. I have to rely on an rta to verify the difference at this point.
I am surprised when I listen to something that I haven't heard in a while and it does sound better however.
I know the Russian polystyrene parts can take a super long time to fill in, and I'm thinking maybe the Panasonic pureism were trying to emulate the black gate parts, since they have shown to take a really long time as well.
The midrange thing has gotten better with mine also, but improvement has been so gradual I almost can't tell. I have to rely on an rta to verify the difference at this point.
I am surprised when I listen to something that I haven't heard in a while and it does sound better however.
I know the Russian polystyrene parts can take a super long time to fill in, and I'm thinking maybe the Panasonic pureism were trying to emulate the black gate parts, since they have shown to take a really long time as well.
Hello,
I would like to give my latest impressions about this project. After listening for a while with this board and all the mods I did, again I could not hear a difference in different filter settings.
Than I compared the AK board with my Kali-Piano2.1. RPi DAC with a switching device. Allthough I think the switching device might reduce a little the sq for both, I could compare them in time and was surprised how small the differences were between both DAC. Biggest difference was in the bass and low midrange. Here I preferred the Piano2.1 with a slightly warmer and more punchy performance and slightly more volume in masculine voices. The better soundstage of the AK board I wrote as a first impression that days was not realizable in this test. Probably a slightly better resolution in high f-range but this might be caused by the thinner low frequency performance which usually leads to the impression of more transperency.
As often read here I guess the main influence on soundperformance might have the oitput stage and the op amp used. I had the LME49720 in place and already ordered an AD823 and OPA2227 for another test. I am also thinking about a transformer output directly taken from the DAC - would this make sense for this DAC? How should such set-up look like? I was thinking to first buy some cheap transformers like LTR 110 from Monacor and to set-up like this: (post 3050).
Any recommendation on this? Could I simply connect prim. of the transformer to AOUTRN and AOUTRP (and same for left channel) or do I need serial resistors to avoid overload and maybe ground the mid connection of the prim coil by an R//C (10K and 22uF)?
One benefit of the LTR 110 could be that I could take the smaller 300 Ohm sec. coil as output to reduce the output level - but maybe 5V input is already too much for this transformer so level should be decreased already on prim. side by U devider.. Let me know your thoughts about it...
I would like to give my latest impressions about this project. After listening for a while with this board and all the mods I did, again I could not hear a difference in different filter settings.
Than I compared the AK board with my Kali-Piano2.1. RPi DAC with a switching device. Allthough I think the switching device might reduce a little the sq for both, I could compare them in time and was surprised how small the differences were between both DAC. Biggest difference was in the bass and low midrange. Here I preferred the Piano2.1 with a slightly warmer and more punchy performance and slightly more volume in masculine voices. The better soundstage of the AK board I wrote as a first impression that days was not realizable in this test. Probably a slightly better resolution in high f-range but this might be caused by the thinner low frequency performance which usually leads to the impression of more transperency.
As often read here I guess the main influence on soundperformance might have the oitput stage and the op amp used. I had the LME49720 in place and already ordered an AD823 and OPA2227 for another test. I am also thinking about a transformer output directly taken from the DAC - would this make sense for this DAC? How should such set-up look like? I was thinking to first buy some cheap transformers like LTR 110 from Monacor and to set-up like this: (post 3050).
Any recommendation on this? Could I simply connect prim. of the transformer to AOUTRN and AOUTRP (and same for left channel) or do I need serial resistors to avoid overload and maybe ground the mid connection of the prim coil by an R//C (10K and 22uF)?
One benefit of the LTR 110 could be that I could take the smaller 300 Ohm sec. coil as output to reduce the output level - but maybe 5V input is already too much for this transformer so level should be decreased already on prim. side by U devider.. Let me know your thoughts about it...
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My recommendation for an output would be the audiofeel 2401, the one that is like the 301 that I have, but with an adjustment for D.C. offset. The $37 delivered for this is a bargain.
If you try the lm49720, make sure and decouple right on the pins, under the board, even then it may sound a little thin.
I was able to finally get the full bass response from mine by adding another 100uf to the 100uf that I had after the regs. The discreet op amp runs pretty warm, consuming some juice. That, and swapping out the .1uf after the lt1963 for a Wima fkp1 .01uf.
If you try the lm49720, make sure and decouple right on the pins, under the board, even then it may sound a little thin.
I was able to finally get the full bass response from mine by adding another 100uf to the 100uf that I had after the regs. The discreet op amp runs pretty warm, consuming some juice. That, and swapping out the .1uf after the lt1963 for a Wima fkp1 .01uf.
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