Marantz has released a firmware upgrade for the PMD620 digital audio recorder that solves the biggest issue some users have had with the device. The PMD620 is compact, easy to use, and records excellent quality audio.
But using the original firmware, if you were monitoring your recordings with headphones you would notice a slight lag/echo effect. In other words, you'd first hear the audio from its source, and then a split second later you'd hear the audio come to you through your headphones. This can be disconcerting if you're recording an interview.
The latest firmware resolves the latency issue. You can download the new firmware along with installation instructions from the official PMD620 web site.