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PGXL Noise mitigation + Power ON/Off switch

Sergey KN7K
Sergey KN7K Member ✭✭✭
edited May 2020 in Power Genius XL Amplifier
There are few reviews on eham and few posts here about PGXL Fan's noise.
I understand that PGXL was designed mostly for remote operation.
What about other guys who does not this capability?

After reviewing internal design, I understood that my initial thoughts to change internal Fan's are not going to happen. 
I came up with project to build another enclosure with sound isolation material and place it behind my desk - good project during this Spring isolation.

1. I do not recommend it to anyone unless you are familiar with Airflow and cooling.
2. I do it on my own risk
3. Have it up and running from mid of March at full power and several contests.
4. Initially I had 1 extra fan on the back. During contests with legal power Temp would go up to 62 degree with continuous CQ in CW.
   Since than I installed 2nd Fan and now Temp would keep below 60 degree. Details below.
5. Noise measurement compared to Acom2000A, both sit from me about 30" and after installed in encloser  and placed behind the desk.
    My Radio shack would not measure below 50db, so it will be "Low"

6. Initially I was planning to install small Plexiglas window in front of PGXL LCD screen, but did not do it yet. Currently it is not needed, maybe later.

External Enclosure design:
1. Wooden box built from Home Depot material.
2. Most important points - Front bottom has opening 2" wide for incoming air!
3. All sides have about 1" clear space, top has about 2" clearance
4. Four legs elevated about 0.5-0.7" above the floor - this is to ensure air flow from external Fan's.
5. Two 12cm Fans (12v) running ALL THE TIME at 8.5v to keep them quiet!

Images from beginning to the final (pretty much self explained)

Front top view

Back view


TOP VIEW before cover install - 2" opening in the bottom

First design - with 1 Fan

Final design - 2 fans on both sides pull air all the time, i cannot hear them at all even during standby. 

PGXL installed behind my desk and I only rely on Windows PGXL application.
With latest FW release 3.4.10 Power reading is work properly and I do not have to see front panel of PGXL anymore...

Been on PGXL subject :)

2nd project - remote Power ON/OFF.
There are several ideas published - I purchased 30A Siemens relay on Amazon, put it to external enclose, connected it to WEMO switch and operate from Wemo application on my iPhone.

Here are few images
Wemo switch

Relay Box

Wemo application

My PGXL work properly on all Bands after initial High SWR issues and trip back to Flex in December. I am happy camper now.

While above project does not eliminate noise completely and would be pretty close to the noise that comes from Acom2000A that sit 2ft away from me. 
Also, characteristic of noise is different that Acom2000A (more higher pitch noise), but with above project I can work most the QSO's without headphones!

Sergey, KN7K


  • Doug
    Doug Member ✭✭
    edited May 2020
    I am sure each operator has his/her level of tolerance on noise level. I am a new owner of the PGXL and must say the noise level at my station for my level of tolerance does not come close to requiring such measures. Each to his own but I think in fairness to Flex this might discourage sales of this amp which I feel is over reaching. Just MHO and every ones MMF.
  • Bill -VA3WTB
    Bill -VA3WTB Member ✭✭✭
    edited May 2020
    I was almost going to say the same thing. It seems that no matter how amazing this amp may be, with the high performance, Meffa and the harmonic filter and great build. all people talk about is the fan noise. But nice project Serg.
  • KF4HR
    KF4HR Member ✭✭
    edited May 2020
    I just use noise canceling headphones.
  • Bob Needleman
    Bob Needleman Member ✭✭
    edited May 2020
    I do not own a PGXL, but have owned other solid state HF amps in the past.  They are ALL noisy as compared to most modern tube amps, especially those using the small, high gain  metal/ceramic tetrodes/triodes (eg. 3CX800, 4CX800, 4CX1000, etc).  The issue is that the solid state amp designers must build in adequate cooling of the high power PA MOSFETS  to handle the stress of repeated heating/cooling down that occurs in amateur operation ( I understand that this is not an issue with commercial broadcast solid state transmitter/amp consoles that run continuously and are contained in full sized cabinetry with professionally designed ducted air or water-based cooling systems, etc). What you experience with all amateur solid state amps, especially operating CW or continuous duty modes is an initial low speed, fairly tolerable fan speed. But as you continue transmitting (eg. after 5 mins or so), the PA trannies will heat up to a critical temp and the heat sensing circuits will trigger the fan speed to go up to the next higher speed. This will continue to occur, with increasing fan speed as the PA temp increases. I don't know how loud the PGXL fan is on max. speed, but I do recall complaints about how noisy the Elecraft KPA1500 would get at max speed #7  (some owners likening it to the noise of a  '747 jet at takeoff!). WIth the current state of the art of solid state RF devices, there's really no way around fairly high dB level fans because the cabinetry is not large enough to build in a high capacity air flow system and  if the trannies are not kept cool, they will fail very quickly  and replacing them is an expensive undertaking. So before you buy a PGXL (or any other SS amp) take that into consideration. If all you do is rag chewing on SSB  speaking intermittently for a minute or two, you probably won't mind the fan. If you're doing 'old buzzard' long,drawn out AM transmissions, or contesting over long periods, either accept the fan noise, or remote the RF deck, because it is always going to be there (and that is a good thing to maximize the longevity of the amp).
    Bob K3AC
  • Rick N4RZ
    Rick N4RZ Member ✭✭✭
    edited May 2020
    I commend Sergey on his efforts to make the amp work better for his situation!  His solution helps to mitigate the noise issue with this amp and gives one a method to turn the power off to the amp without having to access the rear panel which may be a problem for those whose access to the rear panel is not easy.  As for all, solid-state amps being noisy, my SPE 2K-FA is quieter than nearly all of the other amps I have owned recently most of which used tubes.        
  • AH0U
    AH0U Member ✭✭

    My PGXL noise is so loud in the shack you can not talk over it to an operator sitting next to you... the PGXL is over 7 feet away but the noise on FT8 will drive you out of the shack.. it was designed as a remote device and that may be the only solution for the noise which is like standing next to a 747 at take off.


  • Butch
    Butch Member ✭✭✭

    Perhaps someday we'll see liquid cooled solid state HF amps. For now, perhaps the FT8 mode will push PG-XL users back to SSB and having real conversations again? Many times the voice and CW sub-bands really are open, just no one using them.

    Butch, KF4HR

  • Mike VE3CKO
    Mike VE3CKO Member ✭✭✭

    Butch I agree. The whole FT-8 one button click computer QSO, even worse those using the fully automated version requiring no human to operate, just nuts. FT-8 or digital hopefully will not replace my DX hunt on SSB but my hearing is getting worse becoming more difficult to pick out conversions even with expensive hearing aids. As much as I mock digital, in the future if my hearing continues to deteriorate, it maybe the only way for me to continue in the hobby.

    When the PGXL was on my desk a few feet from me it was somewhat distracting but when I moved to to a rack mount in one of my gig boxes, on the ground to the left of the desk, it dramatically reduced the fan noise factor. Not an issue at all.

  • Butch
    Butch Member ✭✭✭

    Mike - I tried FT8 just to see what it was all about but after a few QSO's, (uh, I mean data exchanges) I grew bored of it quickly. I wasn't aware FT8 had progressed to a version requiring no human interaction, but as semi-automated as it already was, I guess a fully automated version was inevitable. Having my PC log data exchanges from other PC's would make FT8 even less desirable to me, but, of course, each to their own. I heard one ham say (tongue and cheek), You meet the nicest people on FT8. :D

    Since the latest PG-XL firmware upgrade came out I rarely notice fan noise anymore, unless I'm running SSTV or RTTY. And when the fans do come on, I find the noise tolerable, especially when I'm wearing noise canceling headsets. hi

    Butch, KF4HR

  • Rick N4RZ
    Rick N4RZ Member ✭✭✭

    Mike - I have a major hearing issue as well. What I do to help hear better on the radio is to plug the TV connector device for my hearing aids into the phone jack on my 6600M. It then sends the radio audio to my hearing aids over a Bluetooth connection. Another advantage to this method is that my hearing aids mute the room noise to a great degree when in this mode. This sort of works out like having noise-cancelling headphones tailored to your hearing loss.

  • Mark_WS7M
    Mark_WS7M Member ✭✭✭

    I've owned: ALS 600 which was desktop sold state and it was so noisy it was horrible. Then I got an SPE 1K FA which was great but the moment I pushed it towards its 1k limit it was noisy too. Then I opted for the SPE 2K FA thinking the head room would make it quieter. It did but FT8 can really work an amp and it too will get real noisy after some time.

    I still have the SPE 2K FA as it is a great amp. I purchased the PGXL and from the start I "remoted" it meaning it and my Flex6600 are in my HVAC room which is 20 feet from my op position. The antenna cables come in there anyway.

    I ran shielded and choked cables for key, stereo speakers and a few other things into the op position. So at the op position, audio from the 6600 come into a small mixer and to either head phones or speaker. I key the radio directly using the hardwire line as well.

    I don't do much voice but decided that I can use the USB mic best so I don't have a directly wired mic.

    I put my PGXL in contest mode so the fans work a lot. Assuming they don't fail this is the best solution ever as I sit in total quiet while all the noisy stuff is out in a shed that maintains a good temp due to the A/C unit being in there.

    I realize not everyone can do something like this but in all honesty this is really a great solution. Since everything is on the LAN I can run this station from the op position or my laptop from just about anywhere.

  • W7NGA
    W7NGA Member ✭✭✭

    I love hearing these horrendous noise stories. I can run my Alpha 89, key down full legal limit, all day and night, and all it speaks is a barely audible whisper. A Summer's morning breeze. And that is with the additional optional fan running. After playing Neil Young rock 'n roll guitar licks all day in the recording studio it is nice to have the peace and quiet of the ham shack to soothe the soul. 🤪

  • Larry _ NY8T
    Larry _ NY8T Member ✭✭✭

    It took me a few months to realize I could use the PGXL meffa feature on ft-8, the amp runs way cooler which equals less fan speed/noise.

  • Butch
    Butch Member ✭✭✭

    Larry - Thanks, that's good to know. I think I'll start using meffa on SSTV and RTTY.


  • Kevin_1969
    Kevin_1969 Member ✭✭
    My experience after one day with the PGXL is a mixed bag. The loud fans are way too much for my shack. The amplifier is a remote amp in my opinion. It's a work horse, makes power very easily. But so far the trade off isn't worth the noise when I have an OM Tube amp that can produce 4,000 watts at a fraction of the noise. If you can get about 15' too 20' away it's close too tolerable.

    I'm really surprised at how well it integrates with the 6000 series flex. I was really impressed with how easily the amp produces such copious amounts of power. 45 watts gave me 1500.

    Be ready for the noise when you buy one. In my opinion it's way over the top unless you can remote it.
  • Mike-VA3MW
    Mike-VA3MW Administrator, FlexRadio Employee, Community Manager, Super Elmer, Moderator admin

    I just want to mention this if you are reading this thread.

    Loud is different things to different people. I have friends who have fans on their PCs that I can’t hear but they say it is loud. Loud is really a subjective measurement and it affects different people in different ways.

    We have many customers who have their PGXL in the same place their previous amplifier was located. And, if you want to remote it, it is easy to do and in fact it can be used to increase RF out by limited the length of coax runs and maybe getting the amplifier closer to your 240VAC connection in case you don’t have one in your shack.

    It is for this reason that we sell product that allows you to try for 30 days in your own hamshack and on your own antennas. And, you also get to test the 3 fan settings. Yes, Contest mode and Broadcast mode are Loud, but for the most part, the normal setting is more than adequate.

    I am not sure what version of the PGXL Firmware that Kevin is on, but newer versions are quieter. It is the power supply fan that is the noisiest.

    73 all

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