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Post by flateric on Jan 8, 2010 8:32:24 GMT -5
Happy new year all! I have a Hartke 4 x 10 bass cab, 400W, 8 ohm, I'm wondering what the normal method for wiring is, for these types of cabs. I'd guess it's 4 sets of 8 ohm speakers wired series + parallel in pairs to give total 8 ohm rating? Is there a way to rewire the speakers to give a 4 ohm rating which will allow full power out of my amp head?
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Post by newey on Jan 8, 2010 8:57:06 GMT -5
Flateric-
Happy New Year to you, too! It's been awhile. (Please check your PMs)
Maybe, but why guess? Can't you take a peek under the hood?
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Post by flateric on Jan 8, 2010 9:55:53 GMT -5
Not without voiding the warranty! Just wanted to see first if anyone knew before I get the screwdriver out!
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Post by newey on Jan 8, 2010 10:47:49 GMT -5
Hartke's website, and the .pdf of the manual, don't give this info. I didn't realize that it was a new unit, still under warranty. But I wouldn't worry too unduly. The only thing likely to go wrong with a speaker cabinet is that you blow one or more of the speakers- and in that case they'd probably claim you abused it and refuse to honor the warranty. Plus, if it's just a matter of undoing/redoing a few screws, they'll probably never know you were in there, unless there's a seal you have to break.
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Post by ashcatlt on Jan 8, 2010 13:18:22 GMT -5
I think it's a safe bet that it's wired the way you've guessed. It's a pretty standard configuration. It might be 4 x 2Ω all in series, or 4 x 32Ω in parallel, but...
If it is as you figure, then you won't get it to 4Ω without replacing the speakers. You can get 3.2 or 6.6, but I'd wait for somebody else's advice on that. The 3.2 might be getting toward dangerously low. Also, it seems to me like this sort of "asymetrical" wiring would cause the various speakers to disapate different amounts of power, but I'm not real sure on that.
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Post by sumgai on Jan 8, 2010 14:23:28 GMT -5
flatty,
ash is correct, multiple speakers that are connected asymetrically will receive, and use, power in differing amounts, and the ear will easily be able to detect this phenomenon. While they may withstand this kind of "unbalanced load", they certainly won't sound as good as what we all call "normal wiring", i.e. symmetrical series, parallel, or some combo of both.
In their 8x10 cabs, Ampeg uses 32Ω speakers and wires them all in parallel. This means that 32Ω units are not uncommon, other manufacturers have access to them too. (So far as I know, the rest of Ampeg's line uses either 16 or 8Ω speakers, but they sometimes do a mix-and-match wiring scheme. My 410HLF has a series/parallel setup of 8Ω units, giving me 8Ω of total impedance.)
Unless the screws are buried within some kind of protective barrier (plastic that breaks the first time, etc.), then you should be able to gain access to them, all the while leaving no trace of your "entry" to the cab. Generally speaking, most cabinet makers realize and understand that users, and/or repairmen, aren't going to take/send the cab back to the store/factory for a "quick check" of what's happening - they're going to look for themselves to see if the problem can be repaired without such hassles.
I'd double-check to see if Hartke is truly such a bunch of assmunches as to void the warranty if there even appears to be any kind of such "field testing", or if it's only the "service" policy of the store where you bought it (be it brick-and-mortar or online). If it's the store, inform Hartke. If it is Hartke, then you'll need to carefully evaluate their propensity for customer-hostile policies versus the perceived benefits.
BTW, in the USA, the Moss-Magnuson Act of 1972 precludes this kind of crap. A user has the right to decide the extent of a problem within his/her means, and can still expect full warranty coverage, should the need arise. Obviously there are some certain, and rational, limitations on this, but for the most part, it works fine. Is there anything like that over there in GB?
HTH
sumgai
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Post by JohnH on Jan 8, 2010 15:14:11 GMT -5
I also expect that you have 4 x 8 Ohm drivers wired series/parallel for 8 Ohms.
The other mathematical ways to get 8 Ohms out of 4, are 4 x 32 Ohms in parallel and 4 x 2 Ohms in series. None of these three possibilties have any way to get them all working together at 4 Ohms. So theres no need to open the cab to find that out, unless you really want to......
cheers
John
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Post by flateric on Jan 8, 2010 16:48:26 GMT -5
Thx guys, a friend on the UK basschat forum confirmed it was four 8 ohm speakers wired in S+P so I don't want to go asymmetric on the loading. Just have to save up for the matching 15" cab and hire a roadie to cart them about for me
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Post by sumgai on Jan 8, 2010 18:15:54 GMT -5
I was just gonna say, you can indeed have 4Ω of power soaking ability, and it'll handle 800 watts too.... Just "double up" with another cabinet in parallel, and you're good to go! ;D I hear that roadies can be had cheap these days. A case of Guiness and you're all set.
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