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Case fan noise

henrylancehenrylance Member ✭✭
Just wondering ??  After 5 months of living with a Flex 6500 and Maestro,  I have gotten use to all the quirks that happen and the long learning curve.  It is a great radio, and no doubt the newest versions will be even better.

I have just one issue, and maybe it is just me.  The exterior case cooling fans.  I fully understand that cooling is needed, but to me the noise is more than I wish to have on a constant basis.  Unlike many I don’t really like headphones.  The 6500 sits on a desk top about 3 feet away.  Is it maybe just my fans, or are they all pretty noisy  ??  Is there a replacement fan(s), that are better.

Just wondering are the new 6400 and 6600 a lot better in that regard  ??

For now I have gone back to my Kenwood 590SG and an SDR play for a panadapter, and much less noise. 


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  • DavidDavid Member ✭✭
    edited April 2018
    Have you tried put the radio under the desk or isolated way from your operating position? I have mine under the desk behind me in a shelf unit. I don't hear it.
  • Jim GilliamJim Gilliam Member
    edited July 2018

    That is an excellent question. I, also, have a 6500 and find the fan noise unreasonable while sitting in front of it. Fortunately, I do most of my operating with my IOS device in another location. I have two 6500's and both of them have too much fan noise. I have even blown out the radios according to Tim's fine explanation, but the fan noise was unreasonable. I have 6600 on order and, hopefully, the fan noise will be less annoying. I have the 3000 and 5000 and they are about half or less loud than the 6500's.

    Jim, K6QE

  • Bill EnglishBill English Member
    edited January 24
    I have a 6300 and I don’t hear anything objectionable. My PC makes a lot more noise than the Flex. I know it’s cooling by looking at the temperatures in DDUtil. Even in Rtty at 50-60 watts in a contest it doesn’t get that hot, and when I stop transmission, the temp drops very fast.. Maybe you have a fan issue. A bearing perhaps?
  • W5APW5AP Member
    edited April 2018
    I have a 6600M and so it sits on the desk in front of me
    and yes....the fan noise is excessive. i was surprised
  • RiaRia Member ✭✭
    edited November 2019
    The fan noise even from my 6700 is not what I'd consider excessive. What kind of noise do you get? Mine is less than a computer power supply fan. The 6600 is supposed to be even quieter.
  • Duane_AC5AADuane_AC5AA Member ✭✭
    edited May 2018
    My 6600 (not M) is nearly silent - I can barely tell a fan is running.  My prior 6500 had some fan noise, but nothing near what I'd call objectionable.  It never really bothered me.  But I did notice how quiet the 6600 is by comparison.
  • Lionel Lionel Member ✭✭
    edited March 19
    My 6300 fan noise was low and not an issue two feet away. My 6400 is much quieter. Except for the green button and the blue waves it would difficult to tell the radio was running.
  • Mike PresnellMike Presnell Member
    edited April 2018
    I guess I never realized the issue of fan noise with these radios.  I have my 6700 right next to me (less than 2 feet from my ear),  but I have rack-mounted it into a rack cabinet that is convenient for my shack, only about 4 feet high.  With the 6700 rack mounted (no front door - the front is open) I cant hear any fan noise from my Flex.  If racking it is a possibility for you, I'm sure you would be very pleased with the results.
  • Steve - K6SRSSteve - K6SRS Member
    edited May 2019
    My 6500 is quiet enough I never gave it a thought.
  • Bill -VA3WTBBill -VA3WTB Member ✭✭✭
    edited April 2018
    To me the fan noise on the 6500 is not objectionable. It is about the same as my computer power supply. I think some expect the radio to be almost silent. Too bad your using a much lower performance radio because of fan noise.
    And yes the 6400 and the 6600 make much less noise because of the larger fan and slower RPM.
  • KY6LA_HowardKY6LA_Howard La Jolla, CA. Paris and Sablet FranceMember ✭✭✭
    edited April 2018

    Perhaps you have a noisy fan with bad bearings...

    My 6700 is very quiet... sits underneath one of the monitors on my desk about 20" from my ears

    I did put a $10 Laptop Cooler underneath the radio (powered from the Radio USB Port- yes I know Tim does not like that use of the radio as a power source) which definitely helps keep the fans from spinning up even under heavy loads.

    Did some tests on FT8 with and without the laptop cooler...   Without the cooler running SO2R, the 6700 fans will start to spin up after about 10 minutes.. With the cooler, they never spin up.

    Even when they spin up the noise level is never as bad as some of my computers in the shack

  • Jeff W7NEEJeff W7NEE Member ✭✭
    edited April 2018
    My 6600 sits on the desk right next to my operating position and it is super quiet. I can’t say I have ever noticed the fans running!
  • Mike_WB8CXOMike_WB8CXO Member ✭✭
    edited April 2018
    My 6600M is quiet! The huge fan inside looks to be running at quarter speed. Perhaps my hearing is worse than I thought
  • Mike_WB8CXOMike_WB8CXO Member ✭✭
    edited June 16
    I can’t confirm 6500 fan noise but my 5 year old ( has it been that long already) 6700 has been running 24/7 and the fans are still quiet! Seems like with fans YMMV...
  • DH2IDDH2ID Member ✭✭
    edited April 2018
    Well, I haven't got a Kenwood TS590SG, but my TS2000X is very loud! Much louder than my Flex-6500, in fact. And you should hear my VAIO I7 notebook under full load. It howls like a jet engine, when under full load although not as loud ;-) I run all my TRX in my micro shack with this one notebook.
  • John G3WGVJohn G3WGV Member ✭✭
    edited November 2018
    Noise levels are subjective! As I get older I find myself less tolerant of unnecessary noise and nowadays I build my PCs into soundproofed cases. That makes the 6500 the noisiest thing (apart from me!) in the shack. Mine is under the desk and the noise level is just about OK. I keep on thinking about putting it in a small cabinet. I can see why some people get irritated by it.

    PC cases with large slow running fans and a bit of soundproofing material do a pretty good job and are only marginally more expensive than the cheap noisy ones. It sounds like the 6600 has at least gone some way towards appeasing those of us who crave a quiet life.

    73, John, G3WGV

  • Cal  N3CALCal N3CAL Member ✭✭
    edited April 2018
    Both my 6300 and 6500 had noisy fans which was mildly annoying.  My new 6600 is nearly silent and not annoying at all! 

  • Lawrence GrayLawrence Gray Member
    edited April 2018
    I find the 6500 fans noisy, but I know I have sensitive hearing. The 6500 is the noisiest item in my shack—even the Acom 600S is quieter. I use headphones, so the noise isn’t an issue, other than when using digital modes. I like Howard’s laptop cooler suggestion. I ordered one to try. My fans are clean, the noise is not bearing noise, and the equipment is in a rack, no door, on the operating desk.
  • edited April 2018
    Like Bill, I don't hear anything on my 6500. Only when the fan revs during RTTY at about 50 watts.
  • Bill EnglishBill English Member
    edited April 2018
    Yes sir, when I get the temps up the fan does increase but not bad. I guess this is kind of a per case deal, Some of us have more sensitive hearing than others, more ambient noise in our shacks, headphones, etc. Lots of factors make this about impossible have a one case fits all situations
  • Bob G   W1GLVBob G W1GLV Member ✭✭
    edited April 2018
    Same here.
  • Gene - K3GCGene - K3GC Member ✭✭
    edited November 2018
    Fascinating, It sounds to be purely a matter of perception.  I have, over time had three Flex 6xxxs and I think they all had the same noise level. My computer is almost totally silent.  I can hear the fan on the CPU cooler - just.  My 6300 is a small bit louder but far from objectionable.

    No one has said anything about amplifiers which, in my experience drown out all the rest.  My present amp is a Palstar LA-1K solid state rf sensing 1kw. It is the quietest Amp I have ever had blut still completely drowns out every thing else. 

    I think this is just as individual as your choice of radio or microphone.  I use my Radiosport head set 90% of the time anyway. :) 

  • Bill -VA3WTBBill -VA3WTB Member ✭✭✭
    edited April 2018
    I never hear anyone say, I am running bare foot because I can hear my amp fan....
    People tend to forgive the huge noise amp fans make because they understand the need for cooling the amp, but when It comes to the radio cooling the PA inside, it must not make much noise at all?
    When I turn on my Ameritron AL-811 I can't hear my flex anymore,,cool.
  • Bob  N0ISBob N0IS Member
    edited April 2018


    Sounds to me as though your 6500 fans are running in a speed other that just idle.  Every once in a while my 6500 will suddenly go to a faster speed for no apparent reason at all and it is noticeable.  It will then stay at that speed until it is turned off and then on the next time I wish to use it, but it then comes on at what I call "IDLE".  Would be nice if there were something to look at to see what speed setting the rig cooling fan was running at.  Ran the 6500 in a contest over the weekend and it just broke out of idle on a couple of occasions.  Oh yes, on hot days without the A/C on in the house, I have come into the shack and found the 6500 working hard to cool itself.  I am talking about 85 to 90 degrees "F".

    Bob, N0IS

  • John G3WGVJohn G3WGV Member ✭✭
    edited April 2018
    A moot point! My (small by US standards) linear only makes a noise when it's being provoked and soon quiets down again after the QSO is done. That's rather different to the radio, which tends to be on whenever I am in the shack, fans and all.

    It's a non-issue as far as I am concerned but it is unusual - most radios don't have fans running continuously.
  • Bill -VA3WTBBill -VA3WTB Member ✭✭✭
    edited April 2018
    Good point Bob
    I don't do anything with my radio to make the fans increase. The only time I have heard them ramp up was when doing an up date.
    If they stayed ramped up I don't think I would like that much either.

    Henry, make sure your radio is in the open and nothing blocking the fans,,it really should not be so noisy when the fans are on Idle.
  • Bill -VA3WTBBill -VA3WTB Member ✭✭✭
    edited April 2018
    John, it is important that the fans run all the time. Most any other radio's do not use the same processors the flex does. These processors create lots of heat that need a lot of cooling.
    Much the same way as your computer processor fan, or video card fan.
  • RiaRia Member ✭✭
    edited November 2019
    My fans started making quite a racket shortly before they failed, came up with the dreaded "ERR CPU FAN SPEED." My radio had to take a trip to the mothership in Austin. Now smooth as silk.
  • Burch - K4QXXBurch - K4QXX Member
    edited July 2018
    I have never heard my fan on my 6700.  I don't think I've ever seen the temperature get above 65 degrees.  Is there a certain speed that the fans kick in?

  • Ted  VE3TRQTed VE3TRQ Member ✭✭
    edited December 2019
    I cannot hear the fans in my 6600M, and I sit maybe a foot from it. I can't speak for all 6600's, but mine is certainly quiet. But then I run QRP, never more than 20 or 30 watts out, often only 10 or 15 watts on digital modes, so do not stress the PA chips at all.

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