Mu-metal for reverb tank buzz (with video)

[linty]

Posting this because I've read many inconclusive threads on reducing buzz in spring reverb.

https://drive.google.com/file/d/1A2sZ_M ... sp=sharing

The noise in the video comes from a spring tank driven by a doepfer a-199 with nothing on the input. It's turned WAY up hence the hissing.
You can see very clearly that the magnetic shielding film does a pretty decent job at reducing buzz. Interestingly covering the top of the tank helps too.

Note that magnetic shielding film (mu-metal) is not the same as conductive film like aluminum foil. I tried the same thing with aluminum foil (sorry, not in the video) with no noticeable effect. Link to the specific product I used below.

Next step for me is to decide whether to wrap the reverb tank or built it into a box that is lined with the foil.

https://www.amazon.ca/gp/product/B01HDL ... UTF8&psc=1

[linty]

I ended up wrapping the outside of the reverb tank in mu-metal, then putting apiece on the inside of my case to cover the last side. It worked out great and helped me find a almost noise-free spot. The film wasn't enough to block buzz at any spot in the case, I still had to pick a spot as far as possible from the transformer but for the spot I did pick it made the noise go from annoying to not noticeable. 30 canadollars is a lot for a little sheet of magic foil, but in my case I'd say worth every penny.

Worth noting that it's surprisingly hard to cut, and I wouldn't recommend using a drill to try to cut circles into it.

[SkyWriter]

Yeah mu-metal has a very, very high permeability relative to other commonly available alloys. B-fields can be a pain :0) they just go around and through everything.

It's a last resort. Usually it's better to silence the noise source in EMI sensitive situations.

A reverb tank and residential/commercial space transformer/fluorescent lights seems like a good mu-metal app.

[HenryBurlingame]

Thanks for posting this, this is good to know. I have a spring reverb that has to be in just the right position to not be noisy as hell and I would love to be able to move it a bit closer to me :-).