As I wrote in the 2020 schedule, the Asta DAC came through many changes and iterations, so it was a lengthy process, but your patience will be rewarded: what we are coming with does not appear very often.
Starting at its front side, the Asta offers four inputs: USB, S/PDIF BNC 75 Ohm, S/PDIF RCA, and Toslink. The USB supports eight channel operation, with maximum frequency associated with the chosen master clock frequencies, while the other three inputs are stereo, operating up to 192 kHz.
The D/A stage is based on the ES9018, so this is my first sigma/delta DAC design released as an Audial device. PCM playback is still my priority, even with sigma/delta, simply because only a fraction of music is still available as DSD, however the Asta USB input will support DSD too.
The output stage is most similar to that used in the Audial D-09 DAC. It means that it is a fully discrete, high performance circuit, with no global feedback, using bipolar transistors in the I/V stage, and bipolar and JFET in the output buffer. And yes, since here we have 8 balanced channels, the Asta employs 16 such I/V stages. And since all the channels outputs are both XLR and RCA, the Asta also employs 24 such buffers.
And then, the high performance stereo headphones amplifier is included too.
Asta also includes the volume control, so it is possible not only to use headphones normally and comfortably, but also to connect this DAC directly to the power amplifier. Individual channels gain can be set separately.
As for the other technical details, in a nutshell, the Asta design is what you expect to see from Audial. All the audio circuits’ supplies use also fully discrete, low noise, zero feedback regulators. The parts are high quality, and the circuit board design is thoroughly thought, and came through many phases, so the complex circuits are brought into the apparently simple and elegant layout.
So, even though it is packed with features, the Asta still looks elegant, both inside and outside, with a front plate having, apart from the LCD showing all the necessary information, only one knob, and headphones connector. It can be also remote control operated, but the actual remote control unit will be available later.
More information to follow soon.
Any update ?
Hello,
I’ve just read the discription of your latest dac which is very interesting. I’ve seen mention of 4 inputs which isn’t bad at all, but I’m also wondering about the possibilty of using an external phono preamp device…is there a possibilty, if not now, but later of an input for that? Also, last but not least, do you have any pictures of your latest device at this stage? Stay safe and I hope to hear from you soin.
Hello Pierre,
The analog inputs will not be included in the Asta DAC, so you will still need a preamp to connect the turntable to your system. The Asta internal layout is already pushed to the limits, and it is hard to think about adding more features to it: sure, we want as many features as possible, but no compromises as well.
During this week we will be hopefully back to the scheduled agenda, and so able to discover all the promised information soon.
Best regards, and take care!
Hi Pedja, hope you are safe and well.
Can you say what you make of differences between the ESS 9018 vs 9038 chips?
Also, would you expect the USB input to be preferred here, and how is the volume control described?
Looking forward to hearing more.
Hello Alec,
Yes, safe and well, thanks. Everything moved way more slowly and more difficult than expected, so we postponed the schedule again and again. But that would be the only recent change regarding the Asta.
As for your questions:
I will refrain from using ES9038, for now at least. Its specifications improvement is achieved by paralleling the output stages, which is firstly not something I admire, and secondly this paralleling also produces too high output current, which makes about impossible to design any decent I/V stage for it. Actually, yet the 3.8 mA @ 800 Ohm (of ES9018 and ES9028, and for instance TDA1541A is similar) is quite a stringent requirement for I/V with nice specifications but without global feedback. So, the Asta will remain ES9018, with ES9028 as a possible alternative.
Practically, the USB input is “preferred” for its capability to carry up to 8 channels. Sonically, all the inputs can work well.
The Asta uses the internal volume control of ES9018. So there is a master volume function, but individual channels’ volume can be set too.
Also, the front plate drawing, as a preview, is below. More details will follow.