Many thanks to SWLing Post contributor Jeff McMahon, who notes that he’s just published a new article exploring why the Tecsun PL-660 and PL-680 “twins” aren’t quite twins after all. Jeff compares the two radios in his garage setup and finds that while the PL-660 is more sensitive, the PL-680 has a clear advantage where it really counts outdoors: better audio fidelity without distortion at high volumes.
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I have went through a PL-660 or few over the years. FWIW, and IMHO, the PL-6×0 series were some of the last decent non-DSP SWL portables before the bevy of Si47xx DSP radios arrived.
The Tecsun PL-330 (a Si47xx radio) is often my “go to” portable these days, but that largely because I no longer have a PL-660 or a Sony 7600GR. That said, admittedly, my PL-330 *might* perform marginally “better” than my cheap ATS-20+ (yet another Si47xx radio) with aftermarket firmware. YMMV.
One of the key things that people often forget about with radio design is to ensure that the audio section sounds good. Yes, frequency coverage is nice. Different filter bandwidths are nice. Good AGC is nice, but good audio from the demodulator stage through the speaker is critical.