Original BeePre low voltage hum

[Alonzo]

Hi Yall,
I have the original version of the BeeP that suffers from low input voltage hum. At about 118 v I have to change the setting on my bucking transformer to +3; it has slowly increased to me using the +6 setting. Now +6 does nothing for the hum.
Any ideas on fixing this internal to the BeeP or do I need to source another boosting voltage transformer?
Alonzo

 

[Paul Birkeland]

I'd double check that the 10,000uF caps under the power supply boards are still in good condition.

 

[Alonzo]

Thanks Paul, I'll check them out.

 

[Alonzo]

Visually everything is fine, also passed voltage checks. I ordered some new ones to pop in and see what that does.

 

[Alonzo]

Well rebuilt the power supply boards and I'm back to the original problem (which is something I can live with due to external help). But there's got to be a better way fix this. Off to eBay to search!

 

[Paul Birkeland]

It might help to know what the boosted voltage is that isn't enough to eliminate the hum. Generally, I've just found that those 10,000uF caps get tired and the raw filament voltage drops too low for the regulators to work properly, or the line voltage sags and that dropout issue manifests in that manner, but I haven't observed issues beyond these two.