what protection lamps do i need?
in [Live Sound]
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From: Bob Urz on 12 Jun 2007 00:56 non-biz(a)hotmail.com wrote: >>** Must have a schem of the passive crossover to analyse. Lamps must go >>AHEAD of the crossover - not in series with the horn driver itself or >>their effectiveness is lost. >> >>...... Phil > > > Please explain wht this is more effective to put it ahead of the xover > and how when in series with the voice coil its ineffective. > I was not clear on that. Phil is right on that one. The driver load the crossover sees would vary with how much the bulb is lit. If its before the crossover, the driver load to crossover would stay more consistent. Go down to the automotive supply house. Ask to see some 12v automotive dome lamps. Look for ones that look like a old automotive AGC fuse on steroids. They will have a connection on each end. Grundorf uses these lamps in there crossovers. Its not a cure for all problems. Bob > Bob- thanks but i need a little more data on dome lamps to make a good > decision to do that. Maybe ii need to grab some lamps, scope and a > pulse gen to emperically determine the lamps i need. > > Thanks -eric > ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =----
From: Eeyore on 12 Jun 2007 04:42 Bob Urz wrote: > non-biz(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. > > > Start with at least two 12volt automotive dome lamp bulbs in parallel > (with each other) then the combination in series with the HF and go > from there. 12V is too low a voltage for a 'proper' 1 inch driver's power handling. Graham
From: Eeyore on 12 Jun 2007 04:44 non-biz(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. Without checking the exact power rating of the 2426, I'd initially be looking at something in the region of a 24V 50/55W halogen 'truck headlight bulb' for this. Graham
From: Eeyore on 12 Jun 2007 04:45 non-biz(a)hotmail.com wrote: > Also - i dont have a schematic of the xover, its a generic looking one > that is not JBL or any decent manufacturer. Its on a blue paper type > PCB and looks like a radioshack special. No silkscreen or solder mask > just bare copper traces. From what i was told, its a 2k x-over 6db/oct > slope . Oh dear ! Graham
From: Eeyore on 12 Jun 2007 04:56
Bob Urz wrote: > Go down to the automotive supply house. Ask to see some 12v automotive > dome lamps. Look for ones that look like a old automotive AGC fuse on > steroids. They will have a connection on each end. 12V is not suitable for SR use. Even the tiddly little ~ 10W 'tweeters' you see around require something like a 24V/18W lamp. This was reputedly once a popular size for trucks in festoon pattern (your dome light idea) but I've had trouble sourcing it in small quantities. I've substituted a 24V/21W truck stop lamp bulb instead to good effect with these. The 2426 will handle 100W continuous program so it's going to need a bigger bulb than that ! The 2426H is 8 ohms so that's 28V @ 3.5A I was about to do the calcs but there must be some passive attenuation on the HF driver. Without that info, there's no point going any further. Graham |