Distorted local FM audio on Brad’s Tecsun PL-660

PL-660SWLing Post reader, Brad, writes:

I just got a Tecsun PL-660 after reading many good reviews on the radio, but I have a problem in that there are two 100,000 W FM stations within a few miles of my house and the reception of these stations isn’t as good as some more distant stations.

The signal strength is great but the audio is a bit distorted like it has too much gain or something. If I manually tune the frequency a few hundreths off the “actual” frequency it seems to help. Moving the antenna switch to “normal” or “local” from “DX” doesn’t make much difference nor does using the external antenna. Any ideas what’s going on?

I’m about ready to return it and get a Sony ICF-SW7600GR instead.

This sounds, to me, like the front end is overloading on the PL-660. I don’t live near a blow torch FM station like Brad.

Have any other PL-660 owners had this problem? Any suggestions for Brad?  Please comment!

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30 thoughts on “Distorted local FM audio on Brad’s Tecsun PL-660

  1. Kevin MacNutt

    I have a Tecsun PL-680 with the same issues, distortion on FM on stronger stations that is resolved by tuning the station 50hz up on strong stations, 20hz up on stations with medium strength and weaker or fringe stations are right on the money. I did however try the offset adjustment via the sync control and it resulted in my strong stations being correct and everything else suffering from beed over from neighboring stations. I am guessing this radio die nir hae a This only has an affect on my FM band as AM, SW and Air all work as they should and are quite superb. I’ll live with the issue mostly because sync works so well in the AM bands I am willing to look over the quirkiness in the FM tuner. That said, I find myself reaching for the similar sized, but lower end analog Tecsun R9700DX as it sounds better. My digital tuning needs are mostly met by my Tecsun PL-990 and Radiwow R-108 which are both excellent performers.

  2. Hanno Steenbergen

    I also noticed the same issue on my PL-660 with some of the FM stations. I think that these stations use more frequency deviation than is allowed resulting in a higher bandwidth than the PL-660 filter bandwidth. As it is frequency modulation this causes distortion.

  3. James Patterson

    Concerning the S 2000 I bought one shiped over from Tecson Australia,to New Zealand where I live.All info came in english and Tecson Australia gave me excellent service via emails.Ive had no probs with it since it arrived via AIR Freight.I tested it side by side with my trusty PL660 and found no distortion at all on very distant HF SSB stations,of which are my main interest rather than just SW radio stations ( compared with the 660).I found it very user freindly and alot more controls than the 660.If you learn how to use the S2000 properly you will find it’s a far better radio but at a much higher price,but yes you are paying for higher quality.
    About the 909x Sangean,that I also have,I find the telescopic antenna works okay on HF/SW if you tie a lenght of copper wire to it,and hang it higher than the antenna its self,extending it.Also where the external antenna connection is, plug in the suplied antenna roll out wire and tie it to a hook on your wall or outside to a tree.You will notice a great difference in HF receiption.But overall compared to my S2000 and PL660 the Sangean 909x does a great job on it’s telescopic antenna.I think the very first batch of these from the factory were no good on that account.I bought mine over two years ago via an importer and after reading reveiws concerning HF receiption,I can say I havent really found it a problem.FM is of course excellent,but I am a HF SSB monitoring Military etc and on some bands it does receive better than others..Hope that helps.The 909X was their “Flag Ship” radio…..worth getting hold of,it will be a Classic in years to come.One thing I will mention though is I had it in it’s vinal cover and packed away while I was useing other radios and decided to get it out and power it up only last week and I noticed a great discolouration on the screen.Not the digital read-out,but the back of the screen,Turning it off and on makes no difference.So it’s on the “face” of the screen thats changed colour.It’s well out of it’s warrenty now,so I’ll just have to live with it.Not effecting the digital read out at all.Pity it’s happened after paying ex amount of $ for it,just to have one!!

  4. Martin Zardeskas

    Just received the PL-600 from Hong Kong via FedEx. The seller claimed it was new, but the box was re-taped. Total audio distortion, especially on FM, left me quite disappointed. I ordered this radio using eBay and have just initiated a return/exchange request. Let’s hope I hear back from them. I own the Sony 7600GR, but wanted a rotary BFO control as the Sony’s ergonomics leave much to be desired. If the next Tecsun has issues, I will return it and never again trust them. Such a shame Sony is out of the SW business; what happened to the build quality of the 2010 or any Telefunken?

  5. Gayle

    No problems except the airband is almost inaudible even with an outside antenna or near the airport with the whip antenna. Fine on all other modes and SW and ham bands are very good. The BFO does a good job in sideband.

  6. Jeyapaul Samathanam

    After using a PL-660 for three years, and becoming irritated with the manual tuning that has gone haywire, I went for Tecsuns’s flagship, the Tecsun S-2000. It started with a big disappointment. The entire instructions came in Chinese. I wrote to Erin Huang of Tecsun and back came the reply that they basically wouldn’t do anything, as others were satisfied. This is the best example of poor customer care from companies in China. This lady just wanted me to download the English instructions from the internet.

    As for the Tecsun S2000, it’s performance is not very much different from the PL660. In fact the 660 was able to pick weaker SW ham signals better. The only difference is that the S2000 has a bigger sound as it is a bigger set with a bigger amplifier. The S2000 looks very attractive, but I dont think it is worth 4 times the price, compared to the PL660. My PL 660 cost me RM385.00, while the S2000 cost me RM1390.00.

    Would I recommend anyone to buy the Tecsun S2000 ? No , the PL660 does a good job on the Air Band, SW and FM. It’s also much cheaper.

    1. Thomas Post author

      If you’re having problems with PL-660 manual tuning, is it with the tuning knob/encoder? If so, you might try to spay a little contact cleaner (Deoxit or similar) behind the encoder. It might require opening the chassis (I’m not sure because I’ve never performed this myself). Just a thought.


      1. Jeyapaul Samathanam

        @ Thomas its the tuning knob, which frequently shows the frequency going the opposite way to my tuning. But since it is still working really well pulling in the aircraft frequencies, I use it to receive a second aviation frequency while I am on the S-2000 on another. Incidentally, my Tecsun S-2000, too, is beginning to give slight distortion at the beginning of strong transmissions, since the past couple of days. I understand buyers in New Zealand had this problem, also. I think the Tecsun company is slowing down on quality control.

        1. James Patterson

          If its only distorting on strong AM frequencies,espeicaly when tuned to SSB,turn the antunuator switch down and you should fine this relives the problem.I too own the very popular 660 and have made one change to it.Ive installed a bigger tuner knob,and it makes it far easier to turn.Ive cut away a small amount of the carry bag to allow it to fit in.Ive never had a problem with the frequencies going backwards while tuning forwards,however when I bought my first one here in New Zealand,I discovered it had very bad harmonics that would come up on all AM short wave frequencies.Once tuned to a SW frequency,after a very short time,a loud hissing or high pitched tone would blanket out anything I was listening to.It would then start climbing up or down past the tuned frequency,infact it didnt matter what band I was on except the Local Air band,it was always there somewhere.So I returned it and found 6 other radios to be the same.I also found it to be on the 600 model aswell.So I nearly gave up on buying one.Every model I tried was the “Black” one.So I asked for a “Silver” one,and to my suprise and to this very day,after about 3 years of owning and useing it every day and night,it performs so well with no internal harmonics at all.Only one thing I can say though is that it does distort slightly on SSB when receiveing very distant stations.Im a SSB DXer so listening to world wide Utility stations is my main hobby,rather than SW AM stations.

  7. Chris Wyatt

    I have the same issue with my Tecsun PL-660. BBC Radio 3 here in the UK sounds OK (to my ears); though I wonder if that’s due to them not using as much (or no?) DRC. It’s maybe because the sound levels are constantly peaking on pretty much every other station, that the distortion’s evident.

    Not tried the tuning out slightly, but I’ll give that a go.

    I reckon it could be something to do with having a lot of interference and the dual conversion. That said, folding the aerial down and reducing sensitivity to local made no difference, so I’m not too confident about that theory.

    Has anyone found the same issue on the PL-680 and PL-880?

  8. James Patterson

    Sony made solid portable receivers,execpt they are all getting old now,seems Sony are not produceing any more hence the computer age we now live in.But we cant receive any SSB signals on internet can we !I own the Sony SW 55 and SW 760G.Not the 760GR.With these two sets,you need to keep good fresh batteries in them at all times,because they and probably other Sonys are micro computer operated.I let the batteries run right down accidently,in the SW 55.When I turned it on it was dead.I quickly replaced the batteries with new.Well my troubles started.It simply would not switch on.It has a Micro push button,that activates the power,a word “Cal” ( Calabrate) came up on the screen,but then turned its self off again.I pluged in the outside wall adapter power and after four times of trying it aventurly swiched on still with full memories.It seems the total loss of power effected the micro computer/processer.So a warning to all Sony owners,keep good batteries in them!!

  9. Brad

    Thanks for all the comments. I ended up exchanging the Tecsun for the Sony. The Sony doesn’t have the FM overload issue and I’m pretty happy with it other than it’s somewhat of an ergonomic train wreck. Reviews I’d read were mainly critical of the tuning buttons instead of a knob but that doesn’t bother me too much. It’s the tiny switches and wheels on the sides of the cabinet that annoy me. I suppose I’ll get used to them, though.

  10. Chris Freitas

    I have owned my PL-660 for nearly 4 years now, and I have not had any audio distortion on FM. A few months ago, there was some distortion on the AM dial and thought it was something to do with the speaker going out. A fresh set of batteries fixed that problem though.

    It could be low batteries, but possibly lowering the RF gain to local or adjusting the antenna could fix the issue as well. If all else fails, see if you can return it and exchange it with another one.

    In regards to the SW-7600GR, I liked it very much and performs very well. I prefer the PL-660 over it because of better sync and audio but the Sony is still a solid performer. If you don’t trust another Tecsun, you won’t go wrong with the 7600GR for sure.

  11. Larry hagood

    I just got a 660 a couple months ago and it had the same problem. ANY FM station that was strong enough to be full quieting sounded like an over-driven amp connected to a blown speaker.

    I returned it for another one from amazon but it had the exact same problem. AM and SW sound fine. Must be a bad batch.

    1. James Patterson

      Try useing the PL 660 with the telescopic antenna folded down when listening to extra close and strong stations.Pulling it up for weaker stations.But I have no problems with my PL660 wheather the antenna is up or down,no distortion or clipping of other nearby FM stations at all.I acturly bought my PL660 for other reasons than FM listening.So even though I have listened to FM stations both strong and weak on it,im mostly up on the HF bands with the SSB mode switched on.Listening to all the military,marine and air craft utilities that boom in with their reports back to base.If you know the correct frequencies to listen to depending on what part of the world you live in,it makes for fine listening enjoyment!!Thats what us SSB DXers are all about!

      1. Mark Sweigert

        Do you get alot of utility and military channels on the tecsun pl-660 and does it come in clear? I hear alot of good reviews about this radio. How do you like it?

        1. Chris Wyatt

          It’s very sensitive and covers quite a wide frequency range. It’s missing the maritime band, and doesn’t cover anything between MW and the commercial FM band (e.g. police frequencies), but you get airband, and you also get the non-commercial part of the longwave band that airports use.

          Shortwave covers 1711 kHz – 29999 kHz, so you find all sorts on there.

        2. Chris Wyatt

          Mark, you may also want to look at the PL-680. It’s much the same as the PL-660 but with newer components and I think I read it had slightly better sensitivity, though they’re about the same really.

          Best reading the reviews as they would do a better job of explaining it than me. There are some good PL-660 / PL-680 articles on this blog.

        3. James Patterson

          Concerning Military stations etc on the PL 660 yes depending on what country you are liveing in.I live way down under Australia in a country called NewZealand.Two islands,North and South NZ.The Military are very quite here mostly just excersises and thats all and you need to know what times they put out a call if any.Sometimes it’s easier to listen to the military in Australia 3 hours away by jet plane.Even the Airways here are very quite.Im speaking of these stations on HF USB.The PL660 will pull them in depending where you live,useing a good 100 FT antenna aswell.You will never overload the PL660.
          But on the other hand I do find distortion in the SSB mode on very weak stations.But tuning in my other portable radios on SSB at the same weak station I get no distortion.Being so far away from the rest of the world where all the action is can be very disapointing for my hobby of monitoring the Military etc.I think the PL660 being digital tuning probably is the reason for the distortion.

          1. Chris Wyatt

            Hi James,

            Interesting about the SSB issue. I noticed it sounds weak too. I thought perhaps both sidebands sounded clearer because maybe the radio did some clever averaging. I don’t have another radio like this for comparison, so wasn’t sure if it was a flaw or not.


          2. Chris Wyatt

            Heard it’s slightly better than the PL-660, which is also a fantastic piece of kit.

            Another one you should look into is the Sangean ATS-909X, which also seems to be very popular.

            I couldn’t tell you which one is best. I’d suggest reading all the reviews and comparisons. I think the PL-660 is a great radio myself, and I’m very happy with it, but I have limited radio knowledge so I may not have noticed some if it’s flaws.


          3. Mark Sweigert

            I got a tecsun pl680, because I watch a video that a ham operator put on You tube and he compared it to the sangean 909x. He said just like others said if you use the antenna on the radio the reception is bad. I know the pl680 has good reception and the reviews are great. That’s what I went by. I know I made a really good choice. Watch the videos on YouTube. I thought the sangean would be good. That’s a shame it looks like a good radio,but I want something that has good reception for the price.

  12. James Patterson

    I would exchange it for another one first befor the sony.I tested four pl 660’s befor I found one that was okay.Some batches sent to New Zealand were faulty,in that they had loud internal birdies or harmonics over all HF bands,and would climb up and down the frequencies.However I have no probs with the FM band,even though I live in the biggest city in NZ of Auckland.Plenty of very strong FM stations here.Acturly if you want a portable just for FM listening you maybe get yourself a more basic radio as these radios are also made for SSB DXing of which they do a very fine job.They are a speicalised hobbiest gen coverage receiver!

  13. Darshan

    I have a Degen DE1103 that has the same issue. I have to tune 700khz below the station to get a good reception. I also have another DE1103 bought at the same time that does not have this issue. So try to get a replacement if does not have much cost implications.

    I also noticed that this happens more when I am inside a concrete building or a place with higher interference that when I in the clear say my front yard. I have not done further testing but lived to learned with the quirk as the offset is constant for all stations. Oddly the search/auto tune always locks on to the correct frequency rather than best signal strength/better audio.

    IIRC, dx switch would not work with FM (only MW and SW) but I may be wrong.

    1. H Az

      Just got a brand new unit of the PL-660 and out of the box it suffers from this distortion problem. No amount of frequency calibration, antenna adjusting or even DX/LOCAL/NORMAL setting would resolve this. All stations (about 25) for my local area is beamed from the same transmission site atop a mountain about 10 miles away. I do notice however that this doesn’t seem to affect all stations – largely those owned by the same government corporation (and one or two others belonging to separate private entities) . I bought this for SW DXing and FM listening, so it’s kind of disappointing. The seller from China thinks it’s a local interference problem and refuses to offer a return. Sigh. Otherwise a great radio.


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