"Light bulb" protected Ampeg cabs

[Max]

Some time ago I posted a question about my Ampeg SVT 410HE and the fact there was no variation in tone using the dial in back of the cab. Someone posted and said "check the lightbulb" inside. Sure enough, it was out and once replaced there is a huge difference. The horn really brings out the highs and you get a nice range with the control in back. Being a newbie and having bought the cab on EBAY without a manual I'm not sure what causes them to burn out. But they're easy to replace with a brake lamp from the auto parts store. Thought I would pass this along.

[MohawkHarry]

I have the same cab, bought it new in the box. They don't
have manuals. I keep my horn turned all the way off because of the loud clicking and poping of my fingers slapping the strings against my pickup (it's as low as it goes) The bulb protects the horn from blowing.
A cool effect is my bulb lights up on dark stages and illuminates my speakers. When the bulb blows the cab gives of a ****ty sounding hazy fuzz. Keep a spare in your gig bag with a cordless drill or screwdriver.

[Matthias]

Originally posted by Max
I'm not sure what causes them to burn out.

Too much power for the horn (those lamps are so nice to blow instead of the horn )
Joke aside: A common reason (maybe the most common one) is clipping of the power amp. If clipping occurs (if you drive the amp too hard) the amp will put out very much power in the high frequency range.

If your blowing the bulb frequently, you need a more powerful amp.

A cheaper way would be to roll off some bass (!) on your EQ - this can avoid clipping (to a certain extent), because it's the low frequencies wich need tons of power.
So: boosting lows leads to earlier clipping of the amp due to high power demand, clipping can cause damage of the horn/tweeter, to avoid this there are bulb fuses.
Hope this makes sense..

Matthias

[phil_chew]

I am thinking of getting the SVT 410HE too. Can anyone give me a brief review of it? I play a 5-string and I wonder if the low end response is decent enough without having to add another 1x15 cab.

[Max]

I don't think the the 4X10HE handles the low end as well. If you look at its ratings on the ampeg webpage, the 4X10HLF and cabs with a 15" have lower response ratings. As for mine, I have a Fender P and found once I added a 15 the bottom end was much better.

[Sammy Camden]

I have an Ampeg 4x10 HLF and it is one nice cab. I use an AmStd Jazz-V, amongst other basses, through it and it works wonderfully. I AB'd the two Ampeg Classic 4x10 cabinets at the store and bought the HLF. The HLF is a 4ohm/400w cabinet, the other is an 8ohm. Try them both, with your bass and head. I think you'll prefer the HLF.