Is this loud?

Not really, there is a noticeable hum but its not too loud.

My M-400 is NOS, but man, it puts out quite a bit of a buzz. Not enough to drive you crazy, but you can hear it across the room. All parts are tight and secured. I guess it's just a loud ballast.

Yeah, I have some ballasts that hummed right out of the box but I have some used ones that are still pretty quiet.

My four year old OVX hums very loudly for it's age, its very random and un expected which lights hum and don't.

Yeah, it's the same for fluorescent ballasts too, and I've have new ones hum right out of the box and 40+ year old ones that are nearly silent.
Kinda like a surprise in every light

When i first got got my Cooper HPS light at Lowe's about a year ago, it was totaly silent. Not the slightest hum. Now, after about a year, you can here a quiet buzzing when it is on.

The humming you get depends on how the ballast was built. If the coils are farther apart you will get a louder hum. If the coils are close together, the less the hum is. And when ballasts get older the coils get more unstable meaning it hums louder.

Yep the coils become loose over time and vibrate, making a buzzing sound.

My Model 25 FCO is pretty quiet.

But if I ever get an extra Model 25 I can send one to you. Denver is FULL Of these in service (Drop lens AND FCO) and get taken down from service all the time. It won't be TOO hard to get another one of these.

Warwick and West Warwick, RI has lots of drop lens 25s. Pawtucket has lots of these in FCO. All the FCO are 250w and most of the SCO are 250 with some 400w.

We don't actually have many here but in Mississauga (the city just south of me) they have tons, most are 400 watt HPS on 50 foot poles.

Most of the model 25's in Denver are 250w HPS, a few are 400w HPS, but the only two I remember got replaced. (One was in evergreen and the other was on the intersection of Kipling and 285)

There are probably more out there though, out of the vast selection of Model 25 FCO and SCO's in Xcel Energy territory.

There's also some Model 25s in Toronto, and Richmond Hill too.

I like this

I do too, the model 25 has always been one of my favourites.

It always has been my favourite, they should use them again they are very popular besides westinghouses and powerlites

I agree, AEL should start making the Model 13 and 25 again, then ditch everything else besides the 327. Then they'd have the perfect "family" of lights!

I agree! Model 13's and 25's should be ruling the roads

I like the 13 the best but i also like the 25 and 113 and 13-000.