Many thanks to SWLing Post contributor, Jiri Kaplan, who writes:

Is it possible to modify the new (DSP) DEGEN DE1103 for VLF reception?

Like before, the old Degen version (without DSP), see these videos:

I wonder if instead of the DE1103 I should buy the PL-660 or PL-680?
I think DSP is worse and the old version can no longer unfortunately be purchased.
My main concern is good selectivity and sensitivity, I live in the city, there are many strong signals.

Thank you for your question, Jiri.

I’m certain you can’t use the same modification of the original DE1103 on the DSP version to achieve VLF reception. In fact, unless the DSP chip itself can be hacked, I imagine modding the DSP DE1103 for VLF would be quite difficult.

I hope more knowledgeable SWLing Post readers can comment with a definitive answer.

Regarding the choice between the DE1103 DSP and the PL–660 or PL-680? I wouldn’t hesitate to grab either Tecsun receiver over the DE1103 DSP. Check out my short review of the DE1103 DSP for more info about this particular model’s shortcomings.

You’re right about finding the original DE1103. I did create this eBay link that should help filter out the DSP models from the search results. At time of posting, there were no listings.