Tech Talk with Thorsten - part 1
Holy Cow! What a thread, what a lot of input already! Thank you all.
I have been testing our first prototype this week using Audio Precision 2 test-set, as well as other gear. Below is a photo of my area of the test laboratory.
Sorry for roached table, it has been there since around 2005 and seen a lot of gear come and go. And has scars from one or twenty soldering irons.
Everything works well (the software team did a good job, almost no bugs in the first code release!) and the results are what we had hoped and more for in a DAC worthy to complement the Stereophile Class B rated iDAC.
Too bad that as a result of the input in this thread the final product is going to be so different, that this will be merely a first step. I was going to confirm the specification today to our marketing people, instead I will include them here as a historical benchmark, so you can see what we ourselves intended to do and what results we got so far.
iDSD micro core specification:
USB 3.0 type B Socket
compatible with iPhone,iPod, iPad and Android Devices,
camera kit or USB-OTG cable required
Audio RCA, fixed 2V
Audio 3.5mm Headphone variable, 3.3V maximum output
SPDIF RCA (up to192kHz PCM)
2,800mAH Lithium Polymer battery and USB (selectable),
dual channel super-regulator for DAC
Single Multicolour LED to indicate Signal and Sample Rates
Dual-Core DSD, PCM & DXD DAC by Burr Brown
bitperfect DSD processing, bitperfect PCM processing
(2-DAC Chip; 4-Channel; 8-Signals, custom interleaving for maximum SNR)
PCM: Bit-Perfect Processing and Minimum Phase/Standard digital filter selectable
DSD: Extreme/Extended/Standard Range analogue filters selectable
DXD: Bit-Perfect Processing, fixed analogue filter
HP Volume Control:
precision analogue volume control, < 2dB Tracking error
HP Amp Power:
> 150mW/15 Ohm
THD + N (line):
<0.005% @ 0dBFS
THD + N (HP):
<0.005% @ 0dBFS
117dB(A) @ 0dBFS
111dB(A) @ 2V out
Ultra low jitter Crystal Clock (rms jitter < 300 Femtoseconds)
Audio Path passives:
Tantalum Oxide Thin Film thin film surface mounted resistors,
TDK high stability C0G surface mounted capacitors
Panasonic PolyPhenylene Sulfide stacked film surface mounted capacitors
But that is now already ancient history, time to look forward.
Of course we will keep all the good stuff we were going to include as standard, yet after reading this thread so far, I think we can do even better.
I have been surprised both by the variety of input and by how much thought and effort some of you have put into this.
Thank you all very much. Posters alamakazam and roamling seem to be trying to put our industrial design team out of a job, truly awesome work.
To reiterate, the micro chassis is sized like a cigar box, just like this prototype model.
We are still working through the suggestions received so far, it will take time. A fair few items we can probably add-in quickly, borrowing technology from the shelves of our parent company AMR.
For others we have to conduct a feasibility study, which is happening as I write this.
Edited by iFi audio - 3/27/14 at 3:14am