AK4490 USB Dac with dsd support.

[sonnya]

Originally Posted by MisterRogers

If you can Sonny, give us a peek at the new shield you're working on :-)

I am going to make discrete opamp Sections that are semi symmetrical . Input will be LTP, second stage is an current mirror, followed by an buffer. This Way it will only have "single gain stage".

I could make it symmetrical but complexity will grow a lot.

But more will follow tomorrow morning


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[MisterRogers]

Thanks Sonny - looking forward to it.

[vitalica]

Originally Posted by sonnya

Ok, now i am moving on to the discrete balanced output shield.

How many are interrested in this with my USB Audio DAC?

+1

[sonnya]

The attached opamp design is the one i will use for the discrete output shield.

As we only have 100mA i total to the outputstage we will have an maximum of 15 - 20mA per opamp to be on the safe side.

This opamp will rest at around 14mA.

I have chosen npn bjt in the input stage as the source impedance's are relatively low, and with bjt we will get a lower offset than with JFET which for 2sk2145-BL is around 20mV. For BJT we can get down to 1/10 of that. And because of the symmetrical loading of the opamp, there is no extra offset build up by the mismatch of source impedance's.

2 opamps will be used for balanced and 1 for balanced to singleended conversion on the output per channel.

BR

Sonny

[sonnya]

Just 2 shots from volumio on pi2 with the USB DAC

[pinnocchio]

Do we have to set volumio in DoP mode for DSD or use native mode?

Thanks
Do

[sonnya]

Yes at the moment it has to be DoP mode for DSD


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[pinnocchio]

Thanks Sonny!

This is also what I use, Pi 2 with volumio 1.55

Will start working on it soon. I'm at the Montreal Grand Prix this weekend so I put music on the side for a few days.

I will be using Sigma 22 and Sigma 11 from AMB for powering the DAC.

Ciao!
Do

[sonnya]

I have found a solution for changing filter. The frontpanel makes it possible. The USB DAC reads the selected filter from the front panel as well as sending the type of data stream that it receives.

We have have test an OLED display in december with 64x256 pixels.

This frontpanel has IR receiver. and will be the same used for the preamp.

We will make a brown colored Plexiglas front for it..

BR Sonny

[rogerchou]

Originally Posted by sonnya

I have found a solution for changing filter. The frontpanel makes it possible. The USB DAC reads the selected filter from the front panel as well as sending the type of data stream that it receives.

We have have test an OLED display in december with 64x256 pixels.

This frontpanel has IR receiver. and will be the same used for the preamp.

We will make a brown colored Plexiglas front for it..

BR Sonny

Amazing, these ideas make us more convenient. Thanks a lot.
Please use codes for Apple remote.