MH bulb ringing?

Hi everyone I have been lurking for a while but just decided to register to ask a question

Anyway I have a 70 watt metal halide fixture and have bought a new bulb for it. I used to use a 14k astralux bulb which ran fine in it, but as they no longer make those bulbs I just bought a 20k ushio bulb.

The first bulb I received buzzed incredibly loudly and was told by Ushio customer service that it was something called acoustic resonance and was caused by the bulb, sockets and ballast lining up perfectly. I was assured that this was a very infrequent occurrence but it would decrease the life of the bulb. I returned the bulb and ordered another one and just received it today.

When first fired up the bulb made no buzzing noise and had no problems firing up like the last bulb. After a while, I noticed it buzzing again. This time it is far quieter, but still noticeable when very close to the fixture (close viewing distance). Is this a common occurrence with MH bulbs? While its not as bad as last time, I really am disappointed that this bulb is ringing after waiting 2 weeks to send the old one back and receive the new one. What would you do if this was occurring with your MH bulb/fixture? I dont know what problems down the road this buzzing will cause but it is very unsettling. Will this problem alleviate itself as it burns in? I was also wondering if turning the nipple down towards the water would help this problem.

Thanks for any help you can provide.

Bill Nye

 

What is your ballast (magnetic/electronic and brand name if possible)

 

Thanks for the quick reply

I have an electronic aromat 5EU Hqi ballast. Here is a link from the guy I bought this from a long time ago. 70W 14k Metal Halide Retrofit Kit, with U.V. glass and Reflector. - Nano-Reef.com Forums

The guy who was selling this had the option between Ushio 10k and Astralux 14k so Im pretty sure it should run the bulb correctly. This ballast has been in storage for a couple years as I got out of the hobby for college but it was running my old bulb perfectly while I waited for a new one.


Thanks again

 

hmmm... well i have never heard of the ballast so i cant say for certain but i think it might be magnetic? and that MIGHT be the reason for the sound.
The bulb might be driving the ballast too hard. now remember, i dont know anything about that ballast so that is all based on speculation...

i wish i could give you a positive answer, but i have not heard of bulbs humming unless they were vibrating for some reason :-/

 

hmm well thanks for your help. It says that it is an electronic ballast on the sticker on the bottom. It also says that the ansi code is m139, m143 and m98. I have heard that most DE bulbs are m85 but it ran my last bulb great for a good year, ran it fine now and the seller also had ushio 10k bulbs which had positive feedback in the post.

Im not sure what my next move should be. I was thinking just scrapping this whole thing and picking up a par 38 LED set up but I have heard mixed reviews on leds.

 

Well I just sent back the bulb to Marine Depot, couldn't stand the ringing. Now I got a big decision to make. Got 3 options as I see it

1) Try to find another 70 watt bulb that I like and see if maybe ushios just dont work with my ballast and maybe another bulb will.

2) Buy a new MH fixture. I have seen some cheap ones made/sold by Fish Need it. You usually get what you pay for but I have seen some good reviews on this product. I guess another option would be a viper. Not sure about that one.

3) Par 38 LED fixture. I am somewhat intrigued by this but I have seen alot of complaints about it and people going back to MH after having their corals change colors on them. I hear that because LEDs do not have UV radiation emitted from them this causes corals (especially zoo's) to dull or change color due to not needing to protect themselves from UV.

Maybe I should just make a new thread for this with a poll haha.

 

Well, that one is a new one on me. That ballast is a true HQI pulse start. It should fire and run Ushio bulbs with no issues.... not sure what is wrong.

It is possible that your compacitor is going out on you and leaking voltage at all times. You could try troubleshooting the ballast if you are electrically minded.

XM is also a good bulb brand for the 70W bulbs.

 

Interesting. I am not that great with electronics but am willing to try anything haha. Will I need a volt meter or some similar piece of equipment to troubleshoot this?

 

http://www.repairfaq.org/sam/captest.htm#cttes

Good instructions on testing for a leaky cap.

You will need a good multimeter. If you don't have one, or have never tested one before, you can probably take it to a TV service guy and have him test it for you. Would be safer this way too.

 

Your ballast is M139 or M143 or M98.

Apparently the Ushio 70W 20,000K should be used on an M85:

20,000K Ushio HQI Double Ended - 70W - 5001606

That is most likely your problem ...