[sdiy] TB-303 humming noise problem

[cheater cheater]

Hi Tom,

On Mon, Feb 11, 2013 at 7:34 PM, Tom Wiltshire <tom at electricdruid.net> wrote:
> Didn't you quote Robin Whittle in an earlier mail saying that it was a ground loop problem and that adding an extra earth wire helped? Have you tried that?

Yeah. It helped, but it's not there yet. I first tried by touching a
croc hookup to the headphone plug and the volume pot pin 1, that made
the buzzing quieter. A piece of copper wire and some teflon later the
mod was in place. The buzzing is still very loud when using a
distortion/"guitar compressor". It's pretty bad, but not as bad as it
was before I guess. But the noise is not audible via headphones
connected directly, not anymore.

> Alternatively, reduce the LED current as much as possible. Use high efficiency or low power LEDs, and change the resistors to run them dim. That ought to reduce the multiplexing noise a bit.

Yep, that's definitely a good idea. I'll have to get some parts for
that. I wonder what gains exactly that will bring.

I'm still wondering if one couldn't get any reduction in buzzing
loudness by bypassing the chips responsible for the ripple? I wonder
which chip that would be actually.. ehh.. I guess I'm sort of stupid
here :)


> On 11 Feb 2013, at 14:41, cheater cheater <cheater00 at gmail.com> wrote:
>
>> Hi Richie,
>> I don't really mind the white noise, but the buzzing is pretty bad.
>> How can I mod the TB-303 to lower the level? Do you think any digital
>> parts need bypassing?
>>
>> Thanks,
>> D.