[sdiy] TB-303 humming noise problem

cheater cheater cheater00 at gmail.com
Mon Feb 11 11:58:09 CET 2013

Paul and Gordon,
no disc tants that I can find. It may well be that it's simply a
built-in error, so I'm trying to figure out what places would be good
to add bypass caps. Any tips?


On Mon, Feb 11, 2013 at 9:09 AM, Gordon JC Pearce <gordonjcp at gjcp.net> wrote:
> On 11/02/13 07:45, Paul Anderson wrote:
>> My suspicion is that the LED is being driven using pulse width
>> modulation, and that's what you are hearing. Can you post a link to
>> the schematic? There's probably a capacitor nearby that is in a bad
>> mood.
> Not PWM but multiplexing, and you are hearing switching hash getting back
> into the audio (possibly because something is dragging the chopper PSU
> down).
> Time to check those little disc ceramics, very carefully - now those
> capacitors *do* fail, frequently.
> --
> Gordonjcp MM0YEQ
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