# Eddy Bergman Noise Module

**URL:** <https://lookmumnocomputer.discourse.group/t/eddy-bergman-noise-module/7350>\
**Category:** DIY STUFF\
**Created:** [July 7, 2024, 4:55pm UTC](https://lookmumnocomputer.discourse.group/t/eddy-bergman-noise-module/7350 "2024-07-07T16:55:03Z")\
**Posts on this page:** 1\
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**Author:** ![analogoutput](https://yyz2.discourse-cdn.com/free1/user_avatar/lookmumnocomputer.discourse.group/analogoutput/32/29663_2.png) [@analogoutput](https://lookmumnocomputer.discourse.group/u/analogoutput)\
**Post date:** [July 7, 2024, 5:21pm UTC](https://lookmumnocomputer.discourse.group/t/eddy-bergman-noise-module/7350/2 "2024-07-07T17:21:04Z")

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First, not all transistors produce noise. It’s being used in a mode it’s not designed for and it’s not guaranteed it’ll do the same thing as the next transistor (especially ones from different batches). I would not solder up a noise circuit without first building enough of it on a solderless breadboard to verify the transistor works.

I have breadboarded that circuit and none of the BC547 I had worked, but several 2N3904 did.

If you don’t have a scope, you can try an [audio probe](https://lookmumnocomputer.discourse.group/t/fast-prototyping/1349/164) to trace the signal. At the transistor emitter (or maybe better at the other side of C1) I’d expect the noise to be faint but audible. At the TL074 pin 1 it should be clear and of course at pin 7. If it’s absent in any of those places that’ll narrow down where the problem is. Of course if you have a scope it’ll be easier to check with that.

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