What is you output tube stage, how you connected it to dac? Can you tell us more as I am looking for same. Thanks
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I use the 3A5 version with amorphous 9:1 transformers, PSU choke, and cathode choke.
You have some mods that can be done. -+12v lines. No FR!! Cap. Replace with Kz 47-100uf. Near ak4490 unsolder one FR and replace it in 3.3v digital position. Gold capacitor must go near AK so on both VA L.R should be same FG cap. At dig supply is better black Fr than Fine gold. You have used just half of regulator for 3.3v position. Install another 3.3v reg and supply separately VDIG and VAN 3.3v supply. Desolder ferrite choke. Because dig line is very noisy on scope and noise goes into analog supply line.Use low esr cap 47-100uf on VD 3.3V as i described earlier...FR or os-con
Instal 100uh choke between Tps7a4700 and dac on +5v. That should relaxed sharp sound...
Replace opamp. enough for beginning.
Yes you could instal xmos dirrectly on dac with no wires.
Move xmos away from transformer to another side. And dac also. Move -+12v reg to another side near transformer.
Please , can I explain why it is usually used only 10uF near the 3.3v and 5v terminals? Higher values simply makes no difference or cause any inconvenience?
Check page 10 of the datasheet: https://www.akm.com/akm/en/file/datasheet/AK4490EQ.pdf
Hi,
Could i use de DACR+ DACR- and DACL+ DACL- on AK4490EQ DAC board (red one) from Diyinhk to feed the balanced inputs (XLR) of my integrated amplifier ? and bypass the OPAMP.
Best regards
It will probably work to a fashion but you would be bypassing the LPF filter and Buffer stage which would probably not be right and possibly end up overloading the DAC. I would not recommend it.
If you want to use the raw DAC balanced outputs, I would suggest building a LPF Buffer stage recommended in the Datasheet.
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Ok thanks a lot
Cheers
Forgot to mention that there is a DC offset of half of your voltage (2.5V if you use 5V) which your amp may or may not be happy with. Mine is fine with that. Best to use DC blocking capacitors if it isn't.
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You have some mods that can be done. -+12v lines. No FR!! Cap. Replace with Kz 47-100uf. Near ak4490 unsolder one FR and replace it in 3.3v digital position. Gold capacitor must go near AK so on both VA L.R should be same FG cap. At dig supply is better black Fr than Fine gold. You have used just half of regulator for 3.3v position. Install another 3.3v reg and supply separately VDIG and VAN 3.3v supply. Desolder ferrite choke. Because dig line is very noisy on scope and noise goes into analog supply line.Use low esr cap 47-100uf on VD 3.3V as i described earlier...FR or os-con
Instal 100uh choke between Tps7a4700 and dac on +5v. That should relaxed sharp sound...
Replace opamp. enough for beginning.
Yes you could instal xmos dirrectly on dac with no wires.
Move xmos away from transformer to another side. And dac also. Move -+12v reg to another side near transformer.
Hi, I have a ak4495 dac and it sound surprising good.
So you you seems to recommend using the FG audio grade caps at the analog side VDD and VRef pins. Currently I have Panasonic FM 100uf at VDD and Rubycon ZL 1000uf at the Vref running at 7.1V (I know the caps is a bit of an over kill).
I have 100uf Nichicon KZ and Silmic at my disposal, but I think the Nichicon KZ legs is a bit too thick to fit.
The 3.3V is from a LT3042 with oscon decoupling to the digital while the 7.1v is from an LT1963A
Hi guys,
a simple question , the single-chip AK4497 be ready for sale? where to buy it?
Thanks
... I found this ... pcb with AK4497 ( but without CHIP ) , I did not understand whether it is necessary two AK4497 ?
K4497 NE5534+AK4118 Optical Fiber Coaxial DAC Decoder Board for Aduio Amplifier | eBay
You need two AK4497 for that board.
...thanks..
That will not be sufficient as you need sone sort of low pass filter (LPF) to remove high frequency noise from your amplifiers input. Also in my experience with different DAC filters, removal of capacitors from the signal path has always yielded sound improvements.For shure i pretend to use 4 film caps at outputs to block DC. One cap for each XLR line,
I would definitely bypass the onboard filter as I suspect it has fairly low performance - only single 1uF capacitor on board looks like simple first order filter is implemented, that I am sure AKM wouldn't recommend (I remember for older 4399 it was recommended to use second order LPF with 3 opamps).
My preference is to use transformers, as they remove DC offset and HF noise at the same time. In my case the next stage has sufficient input impedance so I don't need any buffers after the transformer but you might. But this definitely is not a cheap route to take as good transformers are fairly expensive.
I have seen a buffer with a passive LPF designed by Joachim Gerhard here JG buffer - I2S over USB Audio, maybe it could work for you. I plan to try it at some point in the future.
Just my two cents.
Cheers,
Boris
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