Sonar BR-2906 help with rfi

[Robalo]

Finally I have time to work, My little amp is a Sonar br-2906. It's tuned to an AM channel 20, I got 40 watts DK on AM. Then I did the jump mod for SSB. It does 56 DK WINT 150pep. It sounds really good on air, great modulation, but it has some RFI noise. Can someone help me find the problem I made a video displaying what I got going on so far:

 

[nomadradio]

Ah, "RFI noise"? Like the squeal you hear while the mike is keyed?

73

 

[Robalo]

New Ah, "RFI noise"? Like the squeal you hear while the mike is keyed?

Yes SR.

 

[nomadradio]

That sound is from the core of the amplifier's high-voltage step-up transformer. The 12-Volts DC that runs it feeds into a 2-transistor oscillator circuit. This puts a square-wave AC voltage into the primary winding of the transformer. IIRC the feedback to make the transistors oscillate also comes from a winding on the transformer. The frequency of the AC is 1000 Hz or more and vibrates the transformer core enough to make the loud squeal.

No effective way to get rid of that I know.

73

 

[Robalo]

No effective way to get rid of that I know.

No effective way to get rid of that I know.

OK at least it work very good.on ssb i love it. it going be on my mobil,the relay it tick hard and loud. i call it my old secretary .

 

[midnight special]

had a old black cat years and years ago did the same thing,,, just ran it no problem,,,