DIY AK4490EQ HiRez DAC

[Roscoe Primrose]

I have a bunch of similar boards, but I'm outa town until late on the 24th....

Roscoe

[HAL]

Roscoe,
Thanks! I have those in the parts bin. Just have to find them.

Have a good trip!

[Stuart Polansky]

Being the cheapo that I am, I ordered a similar USB-I2S board from DIYINHK (Hong Kong). With the little LED board it was $65. They also have a DAC board with the AK4490 chip. Looks very different from the one that Rich uses. Probably not as good. But, as a package, they are pretty cheap and at least the DAC uses 3.3V, 5V & 12V supplies. Probably a second supply also, but I can't see all the pin labels on the board. Either use it as is, or it can be custom programmed. I know nothing of this, but I bet Rich, Roscoe, TomP, Guy, Bruce and lots of others do.

If you buy TWO, it's $60 off. So if two of you want to go in, it's a really sweet deal!

For your information:

http://www.diyinhk.com/shop/audio-kits/ ... nd_led_pcb

[HAL]

That is a pretty good deal for $100 each when you buy 2. Looks like that one can be run with a microcontroller to do filters and volume control from the DAC. Probably something like the HiFiduino setup would work with the correct register data for the AKM chips.

I already have an AK4495 pc board coming as well to compare to the AK4490EQ. The AK4495 board has selectable filters with the dip switches. Very similar to the AK4490EQ board's power supplies.

[HAL]

The second AK4490EQ board arrived today. Will be trying this one with the Burson discrete opamps for an easy comparison to the LME49720 from Tom.

Radio Shack is out of the pc boards, so still looking in the parts boxes for mine.

[Roscoe Primrose]

TomP gave me two LME49720 8 pin DIP's and tried them after CAF, and I like the sound quality better than the AD827.

Don't be too hasty dismissing the AD827, keep in mind that these boards come out of China, there's a real chance the AD827s are fakes....

My boards arrived today, so more to play with

Roscoe

[HAL]

Roscoe,

Understand.

The AK4495S DAC board arrived today. Will have to get out the RCA connectors and rig a pair up to solder to this board.

This one has the switches for filter selection. Will be trying both slow roll-off filter versions that are the minimum phase styles.

[Roscoe Primrose]

Even Q5000 AD827JNs are $7.50, what's the chance that they're putting a $7.50 part on a $29 board?

Roscoe

[HAL]

Roscoe,
That is why I do not worry about the AD827 opamps. I doubt they are real, and would really be suspicious if they were dual BB OPA627's at $15 each. The OPA627's are in others and way to cheap. They are all being replaced.

My issue with them is they are not a low DC output offset device where the LME49720's are very low. Then the output caps can be bypassed since they are electrolytics.

[HAL]

Found the IC PC board.

Time to start building up the Burson opamp adaptor.

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