View Full Version : Need some help figuring out an amp
02-07-2003, 01:35 AM
Good evening all! Alright, here is the question. I just bought a set of GNX-10's, and I am putting them in a Q-Logic box. I think its 1.0 cubic feet. I have seen mention of a poly fill....what exacatly is that? well here goes, the subs are rated at 175, so I am going to push 150 to each...but I have no clue what type of amp to go with. There are a couple on my list including alpine, MTX blue thunder, and also the Rockford Fosgate. All the amps are rated at 150x2 @ 2ohms...but as a complete idiot and untrusting of most sales people I do not know which one I should get. Money is of course an issue, and I want to keep the amp under 250 if I could. But if anyone can help me out it would be much appreciated. Thanks for the help too! Ya'll have a great day!
02-08-2003, 11:32 PM
well if youre GNX's are DUAL 4 ohm coil... then you can use an amp that is rated 150 x 2 at 2 ohms... if they are single 4 ohm coil then you'll need one that is 150 x 2 at 4 ohms (which will cost $$$) or one that is 300 - 350 x 1 at 2 ohms (two 4 ohm subwoofers wired in parallel is a 2 ohm load).
if you have dual 4 ohm coil GNX's - then the MTX blue thunder 150.2 (150 x 2 at 2 ohm / 450 x 1 bridged into 4 ohms) would be IDEAL... its a GREAT amp. blue thunder 150.2 should cost you like 200 bucks on ebay.. maybe less (new that is).
Note -- the mtx 302 and 8302 are IDENTICAL to the 150.2 -- its the same amp in a different case, and both of those models are currently 200-ish on ebay -- the 8302 is on sale at circuit city for 299 retail.
fosgate has similar models for similar prices, althougth i could't quote you one off hte top of my head.
get back with the impedance of your subwoofers / coil configuation and myself or someone else in the boards here will get you a more specific answer as well as wiring instructions if you need them.
02-09-2003, 06:34 PM
Thanks for the help. I hate to admit it, but I have no clue if mine are dual voice configuration. on the box it just says GNX104, and in the manual it has a seperate listing for the GNX10DVC, so I think it is the single voice coil. Are the DVC's better? Anyway, the impedence is 4 Ohms...you mention 150x2x2ohms. I know that 2 ohms is less resistence, atleast I think I do. Once again the stupid kid thing pops back up. Anyway, let me know what I should do. I have one week before my next time off, so I have a week to configure the perfect amp for my subs. Gotta love military college. Anway, let me know whats up, and I will talk to you later.Thanks,
02-09-2003, 06:54 PM
ok well when you open the subs out of the packaging, flip them over and look at the back by the magnet --- if there is one set of "positive / negative" hookups, then you've got a single voice coil 4 ohm driver.... if there are two sets -- one on one side the other on the opposite side... then you've got a dual voice coil sub.
if they are dual 4 ohm coil... then as i said, the blue thunder 150x2 will be great... or any other amp that is 150 x 2 at 2 ohms ... in this case you would wire your subs in series so that each of them is then an "8 ohm" sub... then parallel wire the two subs and you'll get a single 4 ohm load on the amp -- bridge the amp and you'll get like 300 x 1 into 4 ohms (note that blue thunder 150x2 will actualy do more like 425 x 1 into 4 ohms bridged... its very UNDER-rated).
if you're subs are SINGLE 4 ohm coil... then you need to find an amp that is at least 300 x 1 at 2 ohms... you'll parallel wire them so that u get a 2 ohm load. suggestions would be.. MTX 4250D // Mtx 250D // JBL BP 300.1 // Alpine MRD-300 ... there are many others... they'll all run you like 150 or so on ebay -- like 250 retail stores.
V ... explaination of series versus parallel wiring.... V
series -- amp power positive wire goes into the positive terminal of 1st voice coil -- then the negative terminal of 1st coil is jumped to the positive terminal of the 2nd coil... negative of 2nd coil is then run to the negative of the amp.
perallel -- both voice coil positives are run to the amp psoitive... both negatieves to the amp negative.
once you determine which they are -- the singel or dual VC version... if u need i'll draw / post a wiring diagram for you...
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