[Amps] Amplifier oscillating - any ideas?

[Sean Williams]

Hi All,

Having just got to testing my pair of Gi7bs on 144 MHz, I notice it oscillates quite happily at 478Megs.....

The amp is built to YU1AW easy build design, with one slight modification - I am using a 100pf doorknob as the HT decoupling cap.

Swinging any of the controls has no effect over frequency or power of the oscillation.

I have relocated the anode RFC so it has shorter leads, the grids are well grounded with brass collets that cover 99% of the grid connection and are well bolted to the aluminium chassis.

Any suggestions would be well recieved!

73 De Sean M1ECY