Ekco UL84 Voltage Issue

[Murphyv310]

Thanks Andy.
The G2 needs a "low" impedance path on these sets which is obtained by the existing circuit, (50uf smoother etc). There is no need though to return the 0.01uf back to ground but if you do I'd advise a 1000v, 0.01uf cap as there is HT plus peaks from the primary of the transformer (anode connection) the use of a 1kv cap may be overkill but better to give a generous rating. I'd definitely attach it between the anode and centre tap that goes to the reservoir capacitor.

[Danndad]

Sorry for the very long delay in replying.
I have moved 1 end of the cap to the centre tap, the squealing has ceased and all is good now.
Thanks for all the help.
Danndad

[Kalee20]

Just as a matter of detail - it isn't a centre tap!

The anode winding has the vast majority of turns. The winding which feeds the rest of the radio, via the essential series resistor, is the hum-cancellation winding of comparatively few turns such that the hum in the speaker due to ripple on the reservoir capacitor is cancelled.

Good work, anyway!

[Ed_Dinning]

Hum cancelling winding is typically between 2% and 5% of total primary turns and if wound with same size wire as pri carries slightly higher current so more likely to burn out.

Your mod will remove the hum cancellinbg function but should otherwise work OK

Ed