# Measuring DACs with the QA403 **URL:** \ **Category:** Uncategorized\ **Created:** [April 30, 2025, 2:29pm UTC](https://forum.quantasylum.com/t/measuring-dacs-with-the-qa403/1846 "2025-04-30T14:29:23Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![peppermint](https://avatars.discourse-cdn.com/v4/letter/p/dfb087/32.png) [@peppermint](https://forum.quantasylum.com/u/peppermint)\ **Post date:** [April 30, 2025, 2:29pm UTC](https://forum.quantasylum.com/t/measuring-dacs-with-the-qa403/1846/1 "2025-04-30T14:29:23Z")
Excuse my ignorance but is it possible to use the QA403 to measure a DAC and if so, can you please tell me what’s the setup like? I believe that since the 403 doesn’t have digital outputs this is not possible. However, I’ve noticed here that some users do DAC measurements. ---
**Author:** ![AVO](https://avatars.discourse-cdn.com/v4/letter/a/b2d939/32.png) [@AVO](https://forum.quantasylum.com/u/AVO)\ **Post date:** [April 30, 2025, 5:32pm UTC](https://forum.quantasylum.com/t/measuring-dacs-with-the-qa403/1846/2 "2025-04-30T17:32:02Z")
Hello peppermint The QA402 and QA403 have an Expansion Connector on the front. Masterclock, Wordclock, Bit/Shiftclock and Digital audio data are available The format is I2S which is a standard interface. These signals can be connected to a DAC chip (in case you want to connect a chip) or a I2S to S/PDIF (or AES/EBU for pro applications) converter for connecting to a device. Such converters (e.g. the " Digitale Interface I2S vers SPDIF BNC WM8805 24bit 192kHz" from [audiphonics.fr](http://audiphonics.fr)) are not expensive. If you want to measure a device, just make sure your converter outputs on the connector you want (optical, cinch or XLR). I’m not a fan of Chinese online shops like Alibaba or Banggood but they also have various offers for I2S to S/PDIF converters. Be careful, the Expansion Connector pinout between a QA402 and QA403 is slightly different.