Noisy Keeley Compressor

[Chris oej]

Hi,

I've built a Keeley Compressor based on the below layout. It works fine. However, it's quite noisy. It's making a kind of constant scratching noise, especially when i turn the sustain up. It's happening with both humbuckers and single coils and when there's no guitar plugged in. All the solders look okay.

Does anyone know what causes this?

Thanks

[midwayfair]

The fastest way to pinpoint this is to use an audio probe and follow the audio path. Figure out where the scratching sound is being introduced.