DIY AK4490EQ HiRez DAC

[HAL]

Figured since it was at CAF2016 folks might have some interest in the DIY HiRez DAC description.

Have attached my description of the DAC and parts list.

The AK4490EQ DAC supports all sample rates and bit depths to 24bit/352.8KHz DXD PCM playback. It has DSD capability, but the board used does not allow direct access. I just downsample the DSD DFF files to 24bit/176.4KHz as that is the maximum limit that Foobar2000's plugin allows.

The filters are also selectable, but the board only gives the minimum phase slow rolloff filter that I prefer.

The Analog Devices AD827 8 pin DIP is installed in a nice machine pin socket. Makes it easy to roll you favorite dual opamp.

TomP gave me two LME49720 8 pin DIP's and tried them after CAF, and I like the sound quality better than the AD827. Very easy change. I liked them in the TPA Opus DAC with the Ballsie Lite output board.

Roscoe has suggested removing two power supply caps and mounting them from underneath the board to allow a Burson opamp. I have dual Burson opamps, so may give that a try. Probably will get a second DAC board in case I kill the first. At $28 for the board, good to have a spare.

Attachments

HAL DIY AK4490EQ HiRez DAC.pdf

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[Stuart Polansky]

Thanks for starting this thread. I will definitely be putting one together. Loved the way it sounded at the show. Well done!

[HAL]

Thanks Stuart!

It is a fun project and now very hard to build.

If anyone wants a HAL sticker that builds one, I have more.

[Roscoe Primrose]

I just ordered a couple of these: http://www.ebay.com/itm/291780354724 which I think is the same one. I've already got a couple USB -> I2S capable boards, so I'm putting off the expensive Amanero board for now. It might be interesting to compare two otherwise identical units to see if the Amanero board is worth the extra coin....

Roscoe

[HAL]

Roscoe,
Yes, that is the AK4490EQ DAC board.

Sounds like fun comparison to me.

Since the Amanero USB Async to I2S Bus was one of the first available and sounded better than the M2Tech, I got it years ago. Lots of less expensive ones on Ebay now.

For folks that new Gary Dodd, it was the USB board in his DAC with the Wolfson Micro WM8741 DAC. It used the minimum phase filter selection as well. It all ran off a 12VDC battery.

[HAL]

I have another AK4490EQ board coming as well.

Found my pair of Burson opamps but they are singles and not compatible with the duals. Will have to make an adaptor with wires to fit them into the chassis without mods. Will see what happens.

[Pelliott321]

I use the Amanero USB on my Twisted Pear Buffalo SE, and love it.
Thinking of building this AK board and would like to try another USB board. Which is the one pictured

[David McGown]

I just ordered a different model with the same DAC and a plug-in XMOS U8 card onto the DAC board. Also selectable coax/opticalUSB and a display.

http://www.ebay.com/itm/282011478528

David

[HAL]

David,
Should be interesting as it looks like a uC runs the DAC functions.

Going to find my Radio Shack 20 pin PC boards and make an adapter for the two single Bursons to the AD827 pinout. Will put some bypass caps on the board for power supply stability. Have a bunch of X7R 4.7uF multilayer ceramic caps with leads to use. Put one pair per opamp module on with the power pins on the pc board and tie the cap leads series connected center point to ground on the DAC board.

[HAL]

Going to use the RS IC pc boards to mount the two single Burson opamps and wire them to a machine pin 8 Pin DIP socket as a dual opamp. Add feet and attach to the protoboard. Then any single or dual opamp can be used.

These are the Bursons before the latest design, but should be an interesting trial. The LME49720 was already a sonic upgrade to me over the AD827.

Now I have to find the pc board.

Attachments