Hum in my ESL's

[WrineX]

hi there. im buidling my hybride speakers , a stripped magnepan smga panel for the lower region and the esl for 300hz and up. i have it running allready although i have to move the crossover frequency of the bass a little bit lower still. but i have another problem wich i want to fix first.

my ESL panels have a slight 50 hertz hum, the left and the right. the humming is also there when i unplug the speaker cables. and its gone when i remove the power from them. wich is not strange caus it is probable because of the 50 hertz mains. the High voltage unit is a classic cascade. without transformers. so 230 volt goes direct to the cascade. if had serveral of these cascades and cant remember they hummed. anyone has an idea what it could be ? like caps rotten ? or diodes ?


the cascade is one of Solosound. dutch people will know them i think

[geraldfryjr]

No matter how the Diode stack is fed make sure that on the powersupply out feeding the ESL, that the ground lead and the HV lead (from the top of the stack) are on the same string or bank of capacitors.
Otherwise you will get Hum.

And check for any shorted or leaky diodes as well.

jer

[WrineX]

Thanks for your help gerald , well i just soldered 1 tranformer 12-230 volt in front of the mains input (230) and use a wall tranformer (adapter) wich gives 12 volt to that transformer , so now the Highvoltage is galvanically
seperated. no hum anymore, so i have to buy another pair for the other speaker.

i thought i might as well try


makes me wonder how this system worked for 35 years with hum or with out.

[geraldfryjr]

Cool !!

That would have been my only other recommendation for sure.

Glad you got it working !!!

jer