Dave, thank you very much for the detailed description. I followed advices of Lampizator and made tube output exactly as he described but with WM8741 i did not get an improvement vs stage with LME97420. I used one of the best tubes Telefunken NOS 12ax7.
Perhaps i will try it again with this Dac because i still have the tube outout stage. It might give different result.
I completely agree with NinoSimona that it is a nice Dac to do some experiments.
Perhaps i will try it again with this Dac because i still have the tube outout stage. It might give different result.
I completely agree with NinoSimona that it is a nice Dac to do some experiments.
Hi I changed that cap.
I didn't have a 220uf cap so I used 2x 100uf 16v sepc caps one mounted on top and other under pcb.
I noticed the difference straight away.
I have had a problem with slight distortion in female voices when using op amp output.
I found that if I bridge first two 11k resistors on the + signal from the AK4399 it stops the distortion.
It also seems to give me a much closer sound to what I'm getting from tube output.
Tubes still have a slightly bigger soundstage and the sound Is more central and warmer.
Op amp has slightly more detail.
Yes I bridged them so they are not used in the circuit but only one pair on the + side.
Sounds strange but it went louder and gave me a better sound.
It might be because I am using LME49720HA op amps.
Hi Guys, so finally everything's received, unfortunately that's the only positive message, everything else so far sucks 
, out of 2 trafos 1 damaged, fortunately just the bottom metal frame so fixable, Monday arrived chassis, every pcs. scratched + some of it damaged including front panel and today at the end DAC board, unfortunately without Elna caps as I requested, everything what could go wrong...went wrong 
, actually not, I didn't test it yet so it might be even worse
how it looks now...
http://www.diyaudio.com/forums/gallery/uploads/305587/DSC00839.JPG
I won't touch it until all replacements arrived so hopefully within next 2 weeks, I was so excited and now this...
In the mean time I plan some upgrades of the caps, I marked some board caps and their values below
http://www.diyaudio.com/forums/gallery/showphoto.php/photo/10877
can you tell me what makes or doesn't make sense to change? I was thinking about those aluminum BC wishay (220uf/25V) then those 47uf/25V output Elnas and finally those black filter 10uf/35V Elnas, I wouldn't touch those 3 small blue Sanyo 47uf/6.3V around AK4399 chips and 1 big next to the LT1963A regulator if it's not necessary, what do you think?
other than that, I need to re-solder RCA plugs as they aren't touching back plate properly, those 3 red WIMA caps next to the coax RCA aren't soldered properly and some other cosmetic changes, overall board contain hi spec. components and looks good
, out of 2 trafos 1 damaged, fortunately just the bottom metal frame so fixable, Monday arrived chassis, every pcs. scratched + some of it damaged including front panel and today at the end DAC board, unfortunately without Elna caps as I requested, everything what could go wrong...went wrong , actually not, I didn't test it yet so it might be even worse how it looks now...
http://www.diyaudio.com/forums/gallery/uploads/305587/DSC00839.JPG
I won't touch it until all replacements arrived so hopefully within next 2 weeks, I was so excited and now this...
In the mean time I plan some upgrades of the caps, I marked some board caps and their values below
http://www.diyaudio.com/forums/gallery/showphoto.php/photo/10877
can you tell me what makes or doesn't make sense to change? I was thinking about those aluminum BC wishay (220uf/25V) then those 47uf/25V output Elnas and finally those black filter 10uf/35V Elnas, I wouldn't touch those 3 small blue Sanyo 47uf/6.3V around AK4399 chips and 1 big next to the LT1963A regulator if it's not necessary, what do you think?
other than that, I need to re-solder RCA plugs as they aren't touching back plate properly, those 3 red WIMA caps next to the coax RCA aren't soldered properly and some other cosmetic changes, overall board contain hi spec. components and looks good
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Sad to hear your story kukynas, that's too bad. I hope everything turns out ok, did you message minishow for a solution?
Pictures viewed, I see you have the newest version, with the AK4118. My advise is first to listen to the DAC, with your new transformers and all. It needs some time to burn in. Then you must decide whether you keep the 5534 opamps or not.
Then I would firstly improve analog output power supply, e.g. bigger Elna Silmic II's, maybe with a 100nF bypass, or use a 220nF filmcap between the + and - supply lines of the opamp, as close to the chip as possible.
There's lots of things you can improve, if I have new findings, I'll post a message.
Dave: I understand now. I don't think this is a good idea. It goes louder because of the fact that the gain of the - side gets bigger, because of the lower resistance (almost 0 ) when the two 11k resistors are bypassed. If you want higher gain, I would adjust both - and + the same value.
Pictures viewed, I see you have the newest version, with the AK4118. My advise is first to listen to the DAC, with your new transformers and all. It needs some time to burn in. Then you must decide whether you keep the 5534 opamps or not.
Then I would firstly improve analog output power supply, e.g. bigger Elna Silmic II's, maybe with a 100nF bypass, or use a 220nF filmcap between the + and - supply lines of the opamp, as close to the chip as possible.
There's lots of things you can improve, if I have new findings, I'll post a message.
Dave: I understand now. I don't think this is a good idea. It goes louder because of the fact that the gain of the - side gets bigger, because of the lower resistance (almost 0 ) when the two 11k resistors are bypassed. If you want higher gain, I would adjust both - and + the same value.
I didn't really want more gain but it did improve the sound a lot.
It got rid of a distorted sound I was getting from the mid range.
What made me think of doing this was because if I took my tube output from before these resistors I got a clear sound but if I took it after these resistors it was slightly distorted.
What's even more strange if I short the resistors on the - side as well the distorted sound comes back.
It's like I need more resistance on either the + or minus.
I thought it might be something I have done wrong by using LME49720HA op amps or putting bigger caps in.
It got rid of a distorted sound I was getting from the mid range.
What made me think of doing this was because if I took my tube output from before these resistors I got a clear sound but if I took it after these resistors it was slightly distorted.
What's even more strange if I short the resistors on the - side as well the distorted sound comes back.
It's like I need more resistance on either the + or minus.
I thought it might be something I have done wrong by using LME49720HA op amps or putting bigger caps in.
Are you sure you have LME49720HA ? It's a dual op-amp, pin layout is different from the single one, LME49710(HA). Have a look at the datasheets. This DAC uses single op-amps, so the pins are to be connected accordingly.
But you can use one half of a dual op-amp (with metal can package), as long as you connect the pins right.
But you can use one half of a dual op-amp (with metal can package), as long as you connect the pins right.
Yes I have I think this is where I have gone wrong.
I read on Internet that LME49720HA was better sounding than LME49710HA.
I will order LME4970HA.
It sounds really good at minute but I might damage something with the wrong op amps and them resistors shorted.
Thank you for your help Ninosimona.
Thanks NinoSimona, I got replacement for those 5534, as I mentioned in my previous post I'll try ADA4627-1BRZ and LME49710HA, both of them already prepared.
I'm in contact with all sellers so will sort it out pretty soon...
You meant those 47uf/25V Elnas change with 100/220uf ?
I ordered Nichicon KA range caps from Hificollective.co.uk (btw. great service with reasonable prices) with several values for my second project so will end up with some spares if necessary.
Hope to get everything soon, will keep you posted
Hi Dave, which type of distortion? just background noise, or some crackling, is it volume sensitive?
I'm in contact with all sellers so will sort it out pretty soon...
You meant those 47uf/25V Elnas change with 100/220uf ?
I ordered Nichicon KA range caps from Hificollective.co.uk (btw. great service with reasonable prices) with several values for my second project so will end up with some spares if necessary.
Hope to get everything soon, will keep you posted
Hi Dave, which type of distortion? just background noise, or some crackling, is it volume sensitive?
You're welcome Dave. You don't have to buy the single version, if you swap some pins according to the datasheets. If the dual version is perhaps better sounding, I would try them first. Also be aware that not always genuine parts are sold at ebay.
Once I bought two LME49720 MA (the DIP version) on ebay, advertised as original parts by the seller. They were fakes, sound was distorted, I got my money back. Then I got them from a well known seller, and sound was what it should be.
Good luck, regards
NinoSimona
Once I bought two LME49720 MA (the DIP version) on ebay, advertised as original parts by the seller. They were fakes, sound was distorted, I got my money back. Then I got them from a well known seller, and sound was what it should be.
Good luck, regards
NinoSimona
Hi kukynas
Yes I meant the 47uF Elna SilmicII, decoupling the + and - supply of the opamps. I think you would notice if you make them bigger, say 220 or even 470 uF. Also, as I said, a 220nF filmcap (polyester or polypropylene) across the supply lines close to the opamp (between pin 4 and 7) could improve decoupling, with better high tones. It's easily tried. Several people here on the board reported improvement doing this with the LME49720. Sound gets more refined.
Thanks for mentioning hificollective, forgot them and maybe a good source for parts for me too. Will have a look.
Yes I meant the 47uF Elna SilmicII, decoupling the + and - supply of the opamps. I think you would notice if you make them bigger, say 220 or even 470 uF. Also, as I said, a 220nF filmcap (polyester or polypropylene) across the supply lines close to the opamp (between pin 4 and 7) could improve decoupling, with better high tones. It's easily tried. Several people here on the board reported improvement doing this with the LME49720. Sound gets more refined.
Thanks for mentioning hificollective, forgot them and maybe a good source for parts for me too. Will have a look.
I've been following this thread and probably ready to buy a board. My brother has the Schiit Gungnir with dual AK4399 and it's impressive.
Any recommendations for who to buy it from? I also need a USB option, which looks like 7 pins. Am I right in thinking the XMOS is better than the 6631? Source will be a Mac Mini. Diyhishop do the main board and the XMOS board.
There's one PCB 185x135mm but differently populated. Available from:
happyshop1982
DAC AK4399 x2 +WM8805+NE5534 Preamplifier completed board | eBay
min9988
Hi-end DA-X2B AK4399+AK4399(parallel)+AK4118+LME49710 USB DAC Soft control | eBay
minishow0328
Dual AK4399 DAC with LCD software mode 192K Coaxial Optical Assembled Weiliang | eBay
zoetsang
DA-X2A AK4399 x2 DAC softwave control high-end dual-parallel decoder | eBay
doukmall
DA-X2B+AK4399+AK4118+NE5534 Soft control MONO dual parallel USB DAC decoder | eBay
diyhifishop - with low jitter AK4118
Great Parallel AK4399 DAC software 192K Assembled use low jitter - $150.10 : Enjoy in your hi-fi project, diy tube amp, amplifier diy, amp diy
And the XMOS USB board:
XMOS USB module compatible for AK4399/DAC7/ES9018 - $52.25 : Enjoy in your hi-fi project, diy tube amp, amplifier diy, amp diy
Any recommendations for who to buy it from? I also need a USB option, which looks like 7 pins. Am I right in thinking the XMOS is better than the 6631? Source will be a Mac Mini. Diyhishop do the main board and the XMOS board.
There's one PCB 185x135mm but differently populated. Available from:
happyshop1982
DAC AK4399 x2 +WM8805+NE5534 Preamplifier completed board | eBay
min9988
Hi-end DA-X2B AK4399+AK4399(parallel)+AK4118+LME49710 USB DAC Soft control | eBay
minishow0328
Dual AK4399 DAC with LCD software mode 192K Coaxial Optical Assembled Weiliang | eBay
zoetsang
DA-X2A AK4399 x2 DAC softwave control high-end dual-parallel decoder | eBay
doukmall
DA-X2B+AK4399+AK4118+NE5534 Soft control MONO dual parallel USB DAC decoder | eBay
diyhifishop - with low jitter AK4118
Great Parallel AK4399 DAC software 192K Assembled use low jitter - $150.10 : Enjoy in your hi-fi project, diy tube amp, amplifier diy, amp diy
And the XMOS USB board:
XMOS USB module compatible for AK4399/DAC7/ES9018 - $52.25 : Enjoy in your hi-fi project, diy tube amp, amplifier diy, amp diy
Hi NinoSimona, thank you for your advice, I'll try the output caps (besides main Elna caps) first and see if there's any difference. Hificollective maybe doesn't offer better prices like Mouser etc. but if you add insane shipping cost (45EUR) from Mouser you are better off with HC as their shipping cost within EU is like 4-5 pounds so all in all for small orders HC is much better and cheaper...
keres: will test both of them and see the result
andyjevans:
it all depence if you wanna solder it yourself or would like to buy fully assembled, there are at least 3 layouts of PCB, you can buy it with WM8805(old type) or with 4113 or 4118(newest version) receiver, there's nearly double difference in price, if I'm you I would buy it from diyhifishop or from minishow0328
You'll be fine with any of the USB card but of course 6631A is cheaper, you can find it for $35 shipped
edit: 1 more note, board with WM8805 support only 24/96Khz through optical toslink, the rest 24/192Khz...
keres: will test both of them and see the result
andyjevans:
it all depence if you wanna solder it yourself or would like to buy fully assembled, there are at least 3 layouts of PCB, you can buy it with WM8805(old type) or with 4113 or 4118(newest version) receiver, there's nearly double difference in price, if I'm you I would buy it from diyhifishop or from minishow0328
You'll be fine with any of the USB card but of course 6631A is cheaper, you can find it for $35 shipped
edit: 1 more note, board with WM8805 support only 24/96Khz through optical toslink, the rest 24/192Khz...
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Thanks for that.
I speak pretty good French, though I'm not familiar with the usual slang like "modif" or "alim". Those are obvious enough.
At times, though, it's even more obvious - "Ça donne un super look!".
Probably not very Parisian.....
discrete KRELL regulating circuit?
andyjevans: I would go for the newest version.
At the Doukmall shop, I read that the analog supply for the opamps is regulated with KRELL regulating circuit. Does anybody know what this is about? On the pictures I can see a heat-sinked regulator/transistor , two resistors and a small transistor and a cap.
My version has LM317/337 pair, very basic circuit. It could surely be improved with two super regulators ($$), but is this Krell thing also better?
kukynas, could you perhaps check what components are used for regulation on your board?
Anyway, I don't use the analog regulation on the board, as I use a separate discrete output stage with super regs. I'm just curious...
andyjevans: I would go for the newest version.
At the Doukmall shop, I read that the analog supply for the opamps is regulated with KRELL regulating circuit. Does anybody know what this is about? On the pictures I can see a heat-sinked regulator/transistor , two resistors and a small transistor and a cap.
My version has LM317/337 pair, very basic circuit. It could surely be improved with two super regulators ($$), but is this Krell thing also better?
kukynas, could you perhaps check what components are used for regulation on your board?
Anyway, I don't use the analog regulation on the board, as I use a separate discrete output stage with super regs. I'm just curious...
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