|N9EWO tests 3 Chinese Portables|
Tecsun PL-680 (notes)
sure and view the comparison chart located on the bottom of this
HUGE thanks to "John C." and "Hal H." as without these folks, this page would NOT be here.
General Quality Control Note : As covered around the internet with ALL 3 of the models of these Chinese portables reviewed below, quality control can vary greatly. With the PL-680 test sample (manufactured in May 2017), it was plagued with so many QC issues that made a "100 % proper" test not possible. It also had old firmware which did not allow the calibration of the MW and SW bands to be tested.
Review : TECSUN PL-660
Firmware Version Tested: Unknown
Country of Manufacture: China
Approx. Serial Number of Test Sample (manufactured in March of 2014) : 396201403019xx
GOOD : Dual Up Conversion design . Decent SW/MW sensitivity (whip or external antenna), especially when the synchronous detector that includes selectable sideband, is used. Generally good ergonomics including excellent direct keyboard entry operation. LW and AirBand frequency coverage (not tested). Clean and open audio (even if sounding a bit shrill). Buttons have good tactile feel (see con). Unique 2 speed tuning selector that works well (Fast OR Slow modes only, not both on at once). 2 well-chosen bandwidth filters (for AM mode signals). 2 event timer and sleep functions. 2000 total memory channels. ATS (Auto Tuning Storage) that also operates on SW. 24 hour clock, display separate from frequency. SSB mode is average for price point and usable, includes a SSB fine tune control (see con). 2 step attenuator switch. LCD is large and well laid out (see con). FM Stereo indicator and selector. Built in ni-mh recharge circuit. Includes unregulated AC adapter, padded carrying case and 4 low capacity ni-mh rechargeable batteries.
BAD : Very weak MW / SW / FM signals get cut off with the soft muting circuit and this ill conceived idea cannot be switched off (using the Sync detector helps to tamp this bug, but not always). FM performance only so-so and adjacent channel rejection is fair. SSB and the fine tune control operate strangely and SSB audio contains “buzzy” audio traits that makes for strained use. Frequency display off (on FM about 50 kHz high / SW up to 5 KHz off), a real issue with weak signals being received properly (see text for adjustment tweak). Sync detector equally symmetrically off (but can be slightly off tuned). Auto tuning speed selection (fast and slow together) makes for difficult operation (thank goodness this is can be switched off) .5-step signal strength indicator pins on even the weakest of signals. No frequency slewing buttons. Limited dynamic range more so with external antenna’s at night (curable with the 2 step attenuator). FM whip antenna is still active when external jack is used (not an issue on SW). MW not supported on external antenna jack. Buttons are small and some are recessed to make matters even worse. LCD backlight is dim and no way for continuous operation even when connected to the AC Adapter. Single step tone control is just a high cut off filter. Cabinet quality fair and encoder / volume knobs feel low quality. Battery cover not hinged. No line audio output jack (see text). Confusing “Chinglish” owner’s manual. Included AC adapter cable too short. Power jack uses un-standard NEGATIVE tip.
The PL-660 works
generally very well and usable Sync Detection (over the PL-880....arf
!). No line record output either, which is huge drawback for
us. Good news is the headphone output is so clean one can
CAREFULLY connect this to a “line input” on a recorder
or computer and get fairly good results (just watch the volume
control not to get too loud).
We have the dreaded soft muting circuit where very weak signals can get cut off. If the sync is used on the MW and SW bands it can help the situation, sometimes greatly. The FM band sensitivity was only average on our test sample and can’t separate station as well either. So if you need above average FM Broadcast, this is not the set for you.
SSB while it does better than the PL-880 (massive distortion / clipping), is still not the greatest. Here we have a “buzzy” trait and also some clipping in the audio on really strong signals once in awhile. It's hard to tune and another strange background "whoosh" sound that varies with rotation of the fine tune control (an AGC bug?). Thank goodness it does use the more standard 4 AA battery operation and includes a non-switching and unregulated AC adapter (WARNING : Set uses a negative tip on the power jack !!). This AC adapter works well but the cable is too short however (only 4 feet long). One cannot keep the back light on "full time" even with the AC adapter in use (which is just plain stupid). Dynamic range is also limited with external antenna’s at night, so overloads say on 41~49 meters , but again can be tamed using the 2-step attenuator switch.
Sync detector works well even if the center point was off a bit
with the test sample (so switching between USB and LSB Sync does
not sound the same). It does have a pretty narrow lock in range (maybe
1 kHz either side maximum). But this allows for a tweak on either
side of the signal to allow for a crisper audio response. When
used it can greatly help with weak signal reception. It really
does decrease fading distortion and adjacent channel interference
well. The 2 bandwidth filters get the job done nicely and are
electronically selected on the front panel. There are no side-mounted
mechanical switches to have to fiddle with. It rarely looses lock
even on the weakest of signals (something we can’t say about
the old Sony ICF-SW7600GR, which has a lousy Sync in comparison. See
here for my insight on the ICF-SW7600GR portable .
Tecsun's PL-660 is a nice set for the money spent (provided you don’t receive a dreaded Tecsun-Degen dud, or other bugs, eham link here). It is sold in Black and Silver cabinet colors. On a final note our early 2014 test sample never experienced the SSB or MW drift as reported elsewhere (it's SSB is rock stable for hours on end). Also the variable sensitivity bug reported elsewhere was another one that never cropped up with our later production sample .
FM Calibration Adjustment (Not Tested) : Kaito Electronics reports this hidden function to calibrate the FM frequency (if it's off) with the PL-660 or PL-680.
"Re-calibrating FM, radio needs to be on and set to FM band. Tune to the desired frequency/station you wish to listen to, press "SYNC" for about 3 seconds back light will flash. Tune up until the frequency/station sounds more clear press "1" to confirm re-calibration. If done correctly the correct frequency/station will be displayed on the display. Keep the battery in for all the time." (this probably means that when the batteries are replaced this needs to be done again ??)
: On LATER PL-660 samples the AIR band button can be used (using the
same procedure as above) to calibrate the SW band filters if they are
not centered with any given sample. WIDE and NARROW filters are
independently set. Appears these settings are retained in EEPROM and
can be put back to factory default by just entering the calibrate mode
(AIR or SYNC button) without pressing the "1" confirm key.
© N9EWO, all rights reserved
Review : TECSUN PL-880
Firmware Version Tested: 8820
Country of Manufacture: China
Approx. Serial Number of #1 (defective) Test Sample: 426201312004xx
(The defective sample was even slightly less sensitive on SW than the replacement below)
Approx. Serial Number of #2 Test Sample (manufactured in December 2013) : 426201312005xx
GOOD : Dual Up Conversion analog design that also includes a DSP IF (Si4735) for the decent IF bandwidth filtering. Outstanding super clean MW / SW / FM audio quality with it’s sealed active and passive speaker system (see con). 2-step attenuator switch. Generally good ergonomics including excellent direct keyboard entry. 2 knob fast and slow tuning (allows for super fine tuning on SSB, a rarity on portables in this price category). All keys have very good tactile response. Display button allows for clock to be displayed independently from frequency display. Line Output jack (see con). LCD backlight can be easily switched on full time. Signal Strength / SNR digital display is decent (after one gets used to it). ATS (auto tuning system) that also works on SW. 3050 total memory channels. 1 event timer and sleep function. LW band coverage (not tested). Built in auto Lithium battery charger. A slew of un-documented adjustments for operation tweaks (do a internet search). Stereo-mono indicator and selector. Attractive metal speaker grill and long “snooze bar” on top. Includes a zippered carrying case and one 18650 lithium ion battery.
BAD : Audio may be considered too “bassy” by some (is not selectable). A single-step tone control is nothing more than a simple high cut switch. General whip and overall sensitivity is not so hot (however using a better external antenna makes it reasonably good). Limited dynamic range when external antenna’s in use more so at night (curable with the 2 step attenuator). Very weak MW / SW signals tend to get swamped out in the AGC. No frequency slewing (up-down buttons). Line audio output is bit too hot (high level), but not to any distortion levels. The “unofficial” Synchronous Detector is useless (more distortion and warble than signal). With our test sample SSB modes were are awash with distortion, makes SSB modes also totally useless. Battery cover not hinged. SW bandwidth always defaults to 5 kHz when first selected (in VF mode). Limited "wider" SSB mode bandwidths. MW not supported on external antenna jack. Flimsy whip antenna (top segments are easily bent). Uses an untraditional 18650 Lithium Ion battery for power, standard AA’s operation is not possible. Power input (charging and operation) is via a 5-volt (at 500ma) mini-USB power supply, locating a suitable NON-switching AC adapter is difficult (and NOT included).
it’s IF filter business in the PL880 within the Si4735 DSP chip. So for
the many bandwidth selections offered. We have a bug
where the SW bandwidth always defaults (at first power up) to 5 kHz when first selected (in VF mode). Tinkering with the secret
menus did nothing to correct his either.
Tecsun PL-880 "IF Bandwidth's"
AM Mode : 2.3, 3.5, 5, 9 kHz
SSB Mode : 500 hz, 1.2, 2.3, 3.0, 4.0 kHz
The PL-880 has a killer sounding speaker using a passive sealed internal enclosure. Nice clean audio too with a 9 kHz AM max bandwidth and AB type amplifier. Most of us already know about the stinky sync performance and the “Hidden Menu’s. Our testing was done with DRN to OFF and the soft mute at "zero”.
I'm not a fan of it's 18650 lithium ion battery ONLY operation (no AA battery use). The external DC jack is via a mini-USB port for charging or operation. Using this set connected to a computer or with any “cell phone” or other 5-volt power adapter does not work on MW / SW with the switching power supply RF noise. Our first test sample was actually defective, had no fine-tuning and also a loose whip antenna base. Also the whip antenna has some very thin elements the closer you get to the top. It can bend very easily if not careful.
Biggest "bug-a-boo" with the PL-880 is the downright nasty distortion with SSB modes. No amount of radio adjustments helped to control it . It's so bad as to almost make ones eyes water and SSB modes are totally useless. With the unofficial "Sync Detector" in use the distortion is so bad as to add warble in the mix as well. We can't say if this major issue has been cleared up in later production (reports are mixed) ?
© N9EWO, all rights reserved
"....and the winner is ??..."
Looking for a low cost in this size with decent MW / SW Broadcasting traits ?? Our pick out of these three is the Tecsun PL-660. Even with the PL-880's fantastic audio with MW / SW AM mode signals and FM , the rest of it was a fast downhill slide. SSB is OK and usable on the PL-660 / PL-680, but it has a "buzzy" trait in the audio . How bad can you make a set sound with SSB signals ?? The PL-880 sample we used in our tests has to be one of the worst (portable or desktop) sets for SSB we have ever encountered . It's SW whip sensitivity was poor in our tests too. However the PL-660 / PL-680's FM performance is not the greatest either (but OK). Dave N9EWO
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