Guys, just put together an old Duray strip light fixture, the thin kind with a F15T8 lamp and a thin Robertson L15 "simple reactor" ballast, basically a choke.

Fired it up and it's darn noisy. What do all y'all know about these skinny little choke ballasts? Are they usually this noisy? I can tell the metal channel fixture is making the noise worse, to the point I can't stand to hear it when I want to run one of my vintage F15T8 lamps.

I'm considering getting a NOS Robertson L15A ballast, hoping that a different one will be quieter!

I believe these are sound rated C. Not a surprise it is noisy. I have two of them on the ceiling of my basement entrance, and it sounds like a gymnasium full of MH buzzing in there. The buzzing is worse in warm summer temperatures, too.

I bought these for under cabinet use in the kitchen, installed one, and un-installed it due to the noise.

Maybe a standard choke would fit ?? Never tried it, so I don't really know. Other solution would be a remote ballast.

Thanks sol, I didn't want to get a different ballast and have it do the same thing.
I didn't see the sound rating, but I did see the outdoor rating, so no surprise it's not designed to be quiet.
The typical choke ballast won't fit, channel is like 1.5" wide

Is there a place nearby where you could mount a typical switch box with cover ? That way, you could remote ballast it. I have done this for PL-S lamps, and it seems to work quite well.

Another option would be to find a "wall wart" ballast and connect it to your deballasted fixture.

What about putting some rubber or felt "O" rings between the ballast and the channel to help absorb the vibration/noise ??

Could also try re-varnishing the preheat choke if it's an open coil one. I've been wanting to try it with some of my noisier ballasts. The Robertson slimline chokes would be a bit more annoying. I'm not sure if they can be easily opened up to re-varnish/re-pot.

I'm going to use this noisy fixture in the garage over my tool box, the noise won't bother me there.

I have some vintage colored fluorescents that I want to display indoors, I'm going to find different fixtures for those.
TBH I actually prefer those plastic blacklight fixtures with the aluminum reflector, they are quiet and with colored lamps they can be quite bright.

I guess an electronic ballast would be another option too. You might be able to find one slim enough to fit into the existing fixture, no clue as to longevity but I think I've seen some F15 Lithonia fixtures that were bundled with electronic ballasts.  

EDIT: Maybe something long and slender like a Fullham WH-2 would work pretty well.

I guess an electronic ballast would be another option too. You might be able to find one slim enough to fit into the existing fixture, no clue as to longevity but I think I've seen some F15 Lithonia fixtures that were bundled with electronic ballasts.  

EDIT: Maybe something long and slender like a Fullham WH-2 would work pretty well.

That may work, need to check case dimensions against available space.

I'll be losing the starter, though.

Yeah, a bit of a bummer on losing the starter. I did some more research and it seems like Vossloh Schwabe made a line of 120v 60Hz preheat ballasts that seen to fit into the slim F15 lights. I'm not sure where you can find one of these now as they seem to have been discontinued a while back.

The other option would be to open up the Robertson L15 and see if you can use some varnish on the core and coil or epoxy potting to silence the unit.

I'd love to find some Vossloh Schwabe F15 chokes for 120V but alas, like you say, they were discontinued several years ago...