what protection lamps do i need?
in [Live Sound]
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From: Eeyore on 13 Jun 2007 22:11 TimPerry wrote: > >> You might consider using appropriatly sized back to back zeners in > >> parallel with the driver. > > > > Might you ? I wouldn't ! Some ppl do have the strangest ideas. > > sure, and then we can restart the semiannual war about if clipping blows > speakers. Clipping results in more rms volts (hence power - up to twice as much) being delivered to the load than the amplifier's power rating. Excessive power *will* burn out speakers. There's no debate about it. > >> In effect this makes something called a Diac. > > > > It does NO SUCH THING at all ! > > petty close... either could be used as a clipper. either are used to fire > the gate of a triac No. Not even close. Diacs are something very different anyway. Don't use words you don't understand. > >> It won't effect x-over leading at least until it starts limiting. > >> > >> I believe I saw something like this in an EV cabinet lately. > > > > You didn't. Get some glasses. > > > >> It was a pretty hefty pair of solid state devices in series. > > > > What EV cabinet ? > > i dont remember the model. i have done a couple pair of EV lately for > buddies with the same problem... worn out / intermittant jacks. > > the circuit must work as the horns still work despite being DJized. In which case it's not configured as you described. Graham
From: non-biz on 13 Jun 2007 23:28 Alright, what about a protection circuit using a fet mounted across the lamp in such a fashion that the fet is in saturation passing all the current and then use a zener to create a trip point at which the fet starts to act as a variable resistor, then dumping part of the load across the lamp. That way the lamp only gets current across it when a certain voltage is reached. Then the lamp becomes the compressor to the comp driver.
From: liquidator on 14 Jun 2007 00:00 On Jun 11, 11:06 pm, non-...(a)hotmail.com wrote: > I have some R&D cases wedges loaded with a 2226h 15" ventagap woofer > and a 2426h comp 1" exit driver. The HF is protected by a 1 amp fuse > and i want to change them over to a lightbulb type circuit. The > amplifier used for these wedges is a QSC EX4000 rated at 1250w/side @ > 4ohms. I am needing advice on lamp # to handle protecting the HF > drivers from burnout, but not starve them for power. > > Thanks in advance to all for your help. > > Eric WHite > Pro Audio Services Frankly, I cut the lamps out of all my boxes. I hate the darned things. Whenever you try to idiot proof, humanity just breeds a better idiot.
From: Phil Allison on 14 Jun 2007 01:18 "Eeysore" non-biz(a)hotmail.com > Are you incapable of answering simple questions ? > > I suspect you're beyond / impervious to any help. ** You can lead a donkey to water ...... ...... Phil
From: Phil Allison on 14 Jun 2007 06:14
"Eeysore" > >> cabinet fire, > > That'll only happen if it's poorly installed. ** Not even possible. 1. The glass surface temp of a hot lamp will only slightly darken the surface of any plywood or particle board it is directly in contact with. 2. Where white polyester or acetate lining material is used and contacts the same hot glass, the material shrinks and darkens only. 3. Where yellow fibreglass type material is used - nothing happens. It is only with WRONGLY designed lamp installations that the lamps glow brightly other than on those normally rare occasions of sustained acoustic feedback. On the many such installations I have engineered over the past 25 years, even with disco music programme played at DEAFENING levels, there is no visible lamp glow. ....... Phil |