QA-403-Your Best Estimate

Matt- Your Best Estimate on ship date QA-403-
30/60/90/120 days # of months?? Something at least-

Your Best Estimate on ship date QA-403

I wish I knew. I’m pretty sure the 30 and 60 are off the table. Dates that were previously committed for shipping certain parts have pushed out. No reason given.

Confidence has fallen enough that a QA404 has been started. I wish I had better info…

1 Like

what part is missing?

I am in the same boat where I have found this amazing piece of kit (QA403) that would do exactly what I need for a reasonable price…but cannot buy it. I understand that it must be frustrating for Matt as well as being a business strain (I checked today and all products are out of stock!). I would be perfectly happy with an external power brick instead of relying on the USB 5V if this is what it takes to get some stock back.


Hi Matt. Could you give us a provisional overview of the QA404 in terms of feature set and performance?


Hi @aaa, all subject to change of course but…

  1. Front panel RCA coax for SPDIF TX/RX. This is shared with the front-panel I2S interface, so they can’t be used at the same time
  2. 384Kbps DAC and ADC
  3. Isolation removed
  4. 3-5 dB improvement DAC THDN compared to QA403.

Not sure yet on the date, maybe around first of the year. Front panel 3D is shown below.

Thanks for the very interesting progress report Matt.

Just curious, what would it take to lower residual distortion by, say 10-12 dB over the QA403? Is that possible without a major cost increase?

Also, is it wise to remove the isolation? Is that due to supply chain problems?

Hi @aaa, yes, the isolation is a supply issue. And in spite of TI bringing two new fabs on line this year, they are still quoting delivery times in excess of a year. I think the isolation is always preferred.

The distortion figures are pretty close to what is achieved by the converters, meaning there’s not much more to be had there. The most expensive analyzers out there are using tunable analog oscillators and notch filters to get the last 5-10 dB of performance. The QA480 does the same, but only at 1 kHz.