[Amps] AL-80A question

[Osten B Magnusson]

Friends!

As you maybe know, answers from Ameritron to questions
are kept very short...   The AL-80A transformer is very noisy
when used here in Europe on 50 Hz. Ameritron says:

  >> An aluminum plate can be secured under the transformer to elimate the
        noise.

Is this true, and if so, how large and thick should it be? 

Thanks in advance and 73 de Osten SM5DQC  sm5dqc at algonet.se