Is your regulator single stage or 2 stage? A 2 stage regulator should give a more even pressure and flow output.
CHGuilford

John
I have a few single stage regulators around and one of them does exibit the same problem at low flow rates... almost a rattle or an oscillation somewhat like from a clarinet or saxiphone reed... I wrote it off as a bad regulator and I don't think it is worth the cost of repair but I can be wrong.
Knowing what little I do about regulator design I suspect the valve spring at the diaphraghm is probably too heavy for the application. (A bit of true and accurate advice would be appreciated) It's not something you should attempt to change on your own but a service shop may be able to fix it.

I have no idea if there would be any valid safety issues using the thing so I leave that decision to your discretion.

I own othr single stage regulators that are acceptable at low flow rates and doubt any real benefit would come from buying an expensive two-stage rather than a single stage regulator that works. Most oxyacetylene manuals describe the differences between the two types of regulators in detail, and two-stage regulators are preferred, but both types work, particularly at lower rates of delivery as on smaller torches.

Your regulator is "broken" in my estimation. Is it a used or new regulator?

regards
d