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Thread: Which amp

  1. #1
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    Which amp

    I'm going to get a 10" Jl W3v3 sub in my A3 and wondered whether it would be worth the extra expense of putting a JL 250/1 v1 in against the A1200. Will I notice that much difference in the quality of the bass and do the few extra functions like subsonic filters etc make that much difference in the real world.

    Or then again should I wait until i can get hold of the new version 2 250/1
    Last edited by drew67; 13th August 2007 at 20:59.

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  3. #2
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    the jl audio amps are nice and easy to use
    but i wouldnt buy an amp just on features alone
    the subsonic filter is really only of use if you are using a ported box or free air
    its stops frequencies below the tuning point from reaching the subwoofer and possibly doing damage

    id personally go for the amp with the most credible power output as the frequencies you are playing are so limited it would be difficult to tell like like otherwise
    2003 pearlescent black s4 avant tiptronic - milltek exhaust - pre cats removed - remapped ...
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    Thanks for that. When you say most credible power supply what exactly do you mean?

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    My sub is a JL Audio 10W3 V2 powered by a JL Audio 250/1 V1 amp in my own custom made box and I am very impressed with it.

    The A1200 is 120 W RMS x 1 @ 4 ohm or 200 W RMS x 1 @ 2 ohm at 12.5 V.
    Using a 10" Jl W3v3 you have a choice of a 2 ohm version or a 4 ohm version so if you get the 4 ohm version and supply it with 12.5V you are 130 W RMS down on the same set up with the 250/1 which will make a difference (this difference will be less at 2 ohms and a higher voltage).

    The JL Audio 250/1 is 250 W RMS @ 1.5 ohm-4 ohm (11V-14.5V) basically the amp will supply 250RMS within those figures so the speaker ohms and the power input voltage do not make a difference to the RMS.

    The 250/1 is also a class D amp which is more efficient but does produce higher distortion than AB design of the A1200, however you will not hear any distortion due to the low pass filter.

    The low pass filter on the 250/1 does have the ability to set the octave slope to 12 or 24 dB (only 12 dB is available on the A1200) which can fine tune a system better. JL recommend 24 dB octave slope for W3 range of subs although it is not set in stone I tend to agree on my set up.

    Also the 250/1 has a low frequency boost built in so you can boost the base in a range of 0-15 dB the A1200 is either 0 or 6dB unless you buy the remote base port lead.

    So in summary you can fine tune a system better with the 250/1 and with a 4 ohm speaker it will be a lot more powerful (the optimum power for the 10" Jl W3v3 is 300 w RMS, minimum is about 100 w RMS).

    In the real world with a 2 ohm 10 W3v3 the A1200 will sound great with a 4 ohm not as good.

    The 250/1 is nearer the optimum power for the 10 W3v3 which is probably the most important part.

    Hope that helps
    Craig
    Last edited by timps; 14th August 2007 at 14:47.

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    Thanks for that Craig helped a lot. Went back into the store today and arranged for them to fit a 250/1 v2 (as long as they can get one ordered). The only slight issue will be if it causes any FM interference being a D class amp as it has to go in one specific place and can't be moved around to see if that would get rid of the interference. If it does cause any then they will put an A1200 in with a 2 ohm W3.

    Andy

  7. #6
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    My 300/4 Class A/B causes no interference but the 250/1 class D causes a slight problem in my Avant mainly on MW & occasionally on FM with a weaker station but not always, both amps are directly under the aerial amp.

    I was offered an unbelievable deal on bankrupt stock (take what they had or leave it) for focal and JLAudio components so no way of changing without more than doubling the price from a more financially stable dealer.

    When I fitted the system my work round was to fit a remote turn on isolation switch for the 250/1 in the glove box.

    I dont need the sub for MW (5 live) and I can live without it for the odd days it affects the weaker FM stations.

    All my music is on an 80 gig hard drive Phatbox so its never really been an issue with me.

 

 

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