ad: w5yi

Yaesu FL-2100b with slight hum

Discussion in 'Amateur Radio Amplifiers' started by W4MJR, Jan 22, 2019.

ad: L-HROutlet
ad: l-rl
ad: Left-3
ad: MessiPaoloni-1
ad: Left-2
ad: L-MFJ
ad: Subscribe
  1. W4MJR

    W4MJR Ham Member QRZ Page

    I have a question about my 2100b. Very good working amp in every way except it has a slight hum when transmittimg ssb or cw around 400 watts. Its wired on a 240 volt 15 amp service just to itself. It gets alittle louder if i increase the power to say 500. Reason I ask is I have a Heath SB220 thats very quite and only hear fan running. I've taken it out and tightened all screws and nuts on transformer. Put a few drops oil in fans. Still has that slight hum or vibration sound when transmitting. Is this normal for this amp to have this sound or am I just comparing it to much to my other amp.
     
  2. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I don't own an FL-2100B but have worked on several of them over the years and don't recall any audible hum coming from them.

    Maybe it hums because it doesn't know the words?:)
     
  3. KN4CTD

    KN4CTD Ham Member QRZ Page

    Is it something that has started happening over time or did you just acquire the amp. I bought a used transformer recently for a project that hummed loudly. Come to find out, someone had the primary jumpers/taps wired wrong according to the schematic of the amplifier from which it was removed. Wired it per the schematic and no hum. Just a thought.
     
  4. N8VIL

    N8VIL Ham Member QRZ Page

    My FL-2100B has a very slight hum that gets a tiny bit louder at higher power output. It is not very noticeable and I have to listen for it to hear it. It sounds nothing like a loose laminate or winding. I just took it as normal and it doesn't concern me. It sounds like a transformer that is under load.
    I have 2 of these amplifiers and I may connect the other one to see if the sound is the same.
     
  5. VE3TMT

    VE3TMT XML Subscriber QRZ Page

    My 2100B has the same transformer hum. I believe it is caused by loose laminate. I did manage to suppress about 75% of it by used wood shims, yes wood shims, tapped between the laminates and steel frame. Crazy but it worked.
     
    W4MJR likes this.
  6. W4MJR

    W4MJR Ham Member QRZ Page

    Ok thanks for your input. I was kinda thinking it might have been coming from transformer. That gives me something to check.
    Thanks,
    Mike
     
  7. VE3TMT

    VE3TMT XML Subscriber QRZ Page

    I've also thought about removing the transformer and remoting it in another room. And finally vacuum relays to make it totally quiet. I can't afford a solid state amp o_O
     
  8. N8VIL

    N8VIL Ham Member QRZ Page

    I have not found my relay or slight hum to be of a nuisance. I have made improvements to my amplifier and find it quite reliable.
     
  9. VE3TMT

    VE3TMT XML Subscriber QRZ Page

    I've replaced the caps, diodes and resistor banks, replaced the original relay with a high power version (quieter), added a low voltage keying circuit and LED meter lighting. I still get excellent power out with the original Cetron tubes.
     
    W4MJR and N8VIL like this.
  10. W4MJR

    W4MJR Ham Member QRZ Page

    I look forward to using this along with my other 101 gear. I bought my 2100b about 2 years ago and just never put in line but its there now. I should have been adding the upgrades just never thought of it with my other amp in line.
     

Share This Page